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-rw-r--r--pkg/abi/linux/limits.go2
-rw-r--r--pkg/abi/linux/mm.go12
-rw-r--r--pkg/sentry/limits/limits.go2
-rw-r--r--pkg/sentry/limits/linux.go2
-rw-r--r--pkg/sentry/memmap/memmap.go37
-rw-r--r--pkg/sentry/mm/BUILD1
-rw-r--r--pkg/sentry/mm/address_space.go12
-rw-r--r--pkg/sentry/mm/lifecycle.go24
-rw-r--r--pkg/sentry/mm/mm.go24
-rw-r--r--pkg/sentry/mm/syscalls.go423
-rw-r--r--pkg/sentry/mm/vma.go38
-rw-r--r--pkg/sentry/syscalls/linux/linux64.go15
-rw-r--r--pkg/sentry/syscalls/linux/sys_mmap.go106
-rw-r--r--pkg/sentry/syscalls/linux/sys_rlimit.go1
-rw-r--r--runsc/boot/limits.go4
-rw-r--r--test/syscalls/linux/BUILD15
-rw-r--r--test/syscalls/linux/mlock.cc344
-rw-r--r--test/syscalls/linux/msync.cc20
18 files changed, 947 insertions, 135 deletions
diff --git a/pkg/abi/linux/limits.go b/pkg/abi/linux/limits.go
index b2e51b9bd..e0aa5b31d 100644
--- a/pkg/abi/linux/limits.go
+++ b/pkg/abi/linux/limits.go
@@ -60,7 +60,7 @@ const (
DefaultNofileHardLimit = 4096
// DefaultMemlockLimit is called MLOCK_LIMIT in Linux.
- DefaultMemlockLimit = 64 * 1094
+ DefaultMemlockLimit = 64 * 1024
// DefaultMsgqueueLimit is called MQ_BYTES_MAX in Linux.
DefaultMsgqueueLimit = 819200
diff --git a/pkg/abi/linux/mm.go b/pkg/abi/linux/mm.go
index 3fcdf8235..eda8d9788 100644
--- a/pkg/abi/linux/mm.go
+++ b/pkg/abi/linux/mm.go
@@ -49,6 +49,18 @@ const (
MREMAP_FIXED = 1 << 1
)
+// Flags for mlock2(2).
+const (
+ MLOCK_ONFAULT = 0x01
+)
+
+// Flags for mlockall(2).
+const (
+ MCL_CURRENT = 1
+ MCL_FUTURE = 2
+ MCL_ONFAULT = 4
+)
+
// Advice for madvise(2).
const (
MADV_NORMAL = 0
diff --git a/pkg/sentry/limits/limits.go b/pkg/sentry/limits/limits.go
index ba0b7d4fd..eeca01876 100644
--- a/pkg/sentry/limits/limits.go
+++ b/pkg/sentry/limits/limits.go
@@ -33,7 +33,7 @@ const (
Rss
ProcessCount
NumberOfFiles
- MemoryPagesLocked
+ MemoryLocked
AS
Locks
SignalsPending
diff --git a/pkg/sentry/limits/linux.go b/pkg/sentry/limits/linux.go
index 511db6733..295f9c398 100644
--- a/pkg/sentry/limits/linux.go
+++ b/pkg/sentry/limits/linux.go
@@ -30,7 +30,7 @@ var FromLinuxResource = map[int]LimitType{
linux.RLIMIT_RSS: Rss,
linux.RLIMIT_NPROC: ProcessCount,
linux.RLIMIT_NOFILE: NumberOfFiles,
- linux.RLIMIT_MEMLOCK: MemoryPagesLocked,
+ linux.RLIMIT_MEMLOCK: MemoryLocked,
linux.RLIMIT_AS: AS,
linux.RLIMIT_LOCKS: Locks,
linux.RLIMIT_SIGPENDING: SignalsPending,
diff --git a/pkg/sentry/memmap/memmap.go b/pkg/sentry/memmap/memmap.go
index 28e2bed9b..cf20b11e3 100644
--- a/pkg/sentry/memmap/memmap.go
+++ b/pkg/sentry/memmap/memmap.go
@@ -243,6 +243,40 @@ type MappingIdentity interface {
Msync(ctx context.Context, mr MappableRange) error
}
+// MLockMode specifies the memory locking behavior of a memory mapping.
+type MLockMode int
+
+// Note that the ordering of MLockModes is significant; see
+// mm.MemoryManager.defMLockMode.
+const (
+ // MLockNone specifies that a mapping has no memory locking behavior.
+ //
+ // This must be the zero value for MLockMode.
+ MLockNone MLockMode = iota
+
+ // MLockEager specifies that a mapping is memory-locked, as by mlock() or
+ // similar. Pages in the mapping should be made, and kept, resident in
+ // physical memory as soon as possible.
+ //
+ // As of this writing, MLockEager does not cause memory-locking to be
+ // requested from the host; it only affects the sentry's memory management
+ // behavior.
+ //
+ // MLockEager is analogous to Linux's VM_LOCKED.
+ MLockEager
+
+ // MLockLazy specifies that a mapping is memory-locked, as by mlock() or
+ // similar. Pages in the mapping should be kept resident in physical memory
+ // once they have been made resident due to e.g. a page fault.
+ //
+ // As of this writing, MLockLazy does not cause memory-locking to be
+ // requested from the host; in fact, it has virtually no effect, except for
+ // interactions between mlocked pages and other syscalls.
+ //
+ // MLockLazy is analogous to Linux's VM_LOCKED | VM_LOCKONFAULT.
+ MLockLazy
+)
+
// MMapOpts specifies a request to create a memory mapping.
type MMapOpts struct {
// Length is the length of the mapping.
@@ -303,6 +337,9 @@ type MMapOpts struct {
// mapping (see platform.AddressSpace.MapFile).
Precommit bool
+ // MLockMode specifies the memory locking behavior of the mapping.
+ MLockMode MLockMode
+
// Hint is the name used for the mapping in /proc/[pid]/maps. If Hint is
// empty, MappingIdentity.MappedName() will be used instead.
//
diff --git a/pkg/sentry/mm/BUILD b/pkg/sentry/mm/BUILD
index 744e73a39..5a9185e5d 100644
--- a/pkg/sentry/mm/BUILD
+++ b/pkg/sentry/mm/BUILD
@@ -106,6 +106,7 @@ go_library(
"//pkg/sentry/context",
"//pkg/sentry/fs",
"//pkg/sentry/fs/proc/seqfile",
+ "//pkg/sentry/kernel/auth",
"//pkg/sentry/kernel/futex",
"//pkg/sentry/kernel/shm",
"//pkg/sentry/limits",
diff --git a/pkg/sentry/mm/address_space.go b/pkg/sentry/mm/address_space.go
index 7488f7c4a..e7aa24c69 100644
--- a/pkg/sentry/mm/address_space.go
+++ b/pkg/sentry/mm/address_space.go
@@ -149,7 +149,7 @@ func (mm *MemoryManager) Deactivate() {
// for all addresses in ar should be precommitted.
//
// Preconditions: mm.activeMu must be locked. mm.as != nil. ar.Length() != 0.
-// ar must be page-aligned. pseg.Range().Contains(ar.Start).
+// ar must be page-aligned. pseg == mm.pmas.LowerBoundSegment(ar.Start).
func (mm *MemoryManager) mapASLocked(pseg pmaIterator, ar usermem.AddrRange, precommit bool) error {
// By default, map entire pmas at a time, under the assumption that there
// is no cost to mapping more of a pma than necessary.
@@ -173,7 +173,9 @@ func (mm *MemoryManager) mapASLocked(pseg pmaIterator, ar usermem.AddrRange, pre
}
}
- for {
+ // Since this checks ar.End and not mapAR.End, we will never map a pma that
+ // is not required.
+ for pseg.Ok() && pseg.Start() < ar.End {
pma := pseg.ValuePtr()
pmaAR := pseg.Range()
pmaMapAR := pmaAR.Intersect(mapAR)
@@ -184,13 +186,9 @@ func (mm *MemoryManager) mapASLocked(pseg pmaIterator, ar usermem.AddrRange, pre
if err := pma.file.MapInto(mm.as, pmaMapAR.Start, pseg.fileRangeOf(pmaMapAR), perms, precommit); err != nil {
return err
}
- // Since this checks ar.End and not mapAR.End, we will never map a pma
- // that is not required.
- if ar.End <= pmaAR.End {
- return nil
- }
pseg = pseg.NextSegment()
}
+ return nil
}
// unmapASLocked removes all AddressSpace mappings for addresses in ar.
diff --git a/pkg/sentry/mm/lifecycle.go b/pkg/sentry/mm/lifecycle.go
index 1613ce11d..a42e32b43 100644
--- a/pkg/sentry/mm/lifecycle.go
+++ b/pkg/sentry/mm/lifecycle.go
@@ -22,6 +22,7 @@ import (
"gvisor.googlesource.com/gvisor/pkg/sentry/arch"
"gvisor.googlesource.com/gvisor/pkg/sentry/context"
"gvisor.googlesource.com/gvisor/pkg/sentry/limits"
+ "gvisor.googlesource.com/gvisor/pkg/sentry/memmap"
"gvisor.googlesource.com/gvisor/pkg/sentry/platform"
"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
)
@@ -58,13 +59,17 @@ func (mm *MemoryManager) Fork(ctx context.Context) (*MemoryManager, error) {
mm.mappingMu.RLock()
defer mm.mappingMu.RUnlock()
mm2 := &MemoryManager{
- p: mm.p,
- haveASIO: mm.haveASIO,
- layout: mm.layout,
- privateRefs: mm.privateRefs,
- users: 1,
- usageAS: mm.usageAS,
- brk: mm.brk,
+ p: mm.p,
+ haveASIO: mm.haveASIO,
+ layout: mm.layout,
+ privateRefs: mm.privateRefs,
+ users: 1,
+ brk: mm.brk,
+ usageAS: mm.usageAS,
+ // "The child does not inherit its parent's memory locks (mlock(2),
+ // mlockall(2))." - fork(2). So lockedAS is 0 and defMLockMode is
+ // MLockNone, both of which are zero values. vma.mlockMode is reset
+ // when copied below.
captureInvalidations: true,
argv: mm.argv,
envv: mm.envv,
@@ -77,7 +82,7 @@ func (mm *MemoryManager) Fork(ctx context.Context) (*MemoryManager, error) {
// Copy vmas.
dstvgap := mm2.vmas.FirstGap()
for srcvseg := mm.vmas.FirstSegment(); srcvseg.Ok(); srcvseg = srcvseg.NextSegment() {
- vma := srcvseg.ValuePtr()
+ vma := srcvseg.Value() // makes a copy of the vma
vmaAR := srcvseg.Range()
// Inform the Mappable, if any, of the new mapping.
if vma.mappable != nil {
@@ -89,7 +94,8 @@ func (mm *MemoryManager) Fork(ctx context.Context) (*MemoryManager, error) {
if vma.id != nil {
vma.id.IncRef()
}
- dstvgap = mm2.vmas.Insert(dstvgap, vmaAR, *vma).NextGap()
+ vma.mlockMode = memmap.MLockNone
+ dstvgap = mm2.vmas.Insert(dstvgap, vmaAR, vma).NextGap()
// We don't need to update mm2.usageAS since we copied it from mm
// above.
}
diff --git a/pkg/sentry/mm/mm.go b/pkg/sentry/mm/mm.go
index b1e39e898..c0632d232 100644
--- a/pkg/sentry/mm/mm.go
+++ b/pkg/sentry/mm/mm.go
@@ -95,11 +95,6 @@ type MemoryManager struct {
// vmas is protected by mappingMu.
vmas vmaSet
- // usageAS is vmas.Span(), cached to accelerate RLIMIT_AS checks.
- //
- // usageAS is protected by mappingMu.
- usageAS uint64
-
// brk is the mm's brk, which is manipulated using the brk(2) system call.
// The brk is initially set up by the loader which maps an executable
// binary into the mm.
@@ -107,6 +102,23 @@ type MemoryManager struct {
// brk is protected by mappingMu.
brk usermem.AddrRange
+ // usageAS is vmas.Span(), cached to accelerate RLIMIT_AS checks.
+ //
+ // usageAS is protected by mappingMu.
+ usageAS uint64
+
+ // lockedAS is the combined size in bytes of all vmas with vma.mlockMode !=
+ // memmap.MLockNone.
+ //
+ // lockedAS is protected by mappingMu.
+ lockedAS uint64
+
+ // New VMAs created by MMap use whichever of memmap.MMapOpts.MLockMode or
+ // defMLockMode is greater.
+ //
+ // defMLockMode is protected by mappingMu.
+ defMLockMode memmap.MLockMode
+
// activeMu is loosely analogous to Linux's struct
// mm_struct::page_table_lock.
activeMu ssync.DowngradableRWMutex `state:"nosave"`
@@ -252,6 +264,8 @@ type vma struct {
// metag, none of which we currently support.
growsDown bool `state:"manual"`
+ mlockMode memmap.MLockMode
+
// If id is not nil, it controls the lifecycle of mappable and provides vma
// metadata shown in /proc/[pid]/maps, and the vma holds a reference.
id memmap.MappingIdentity
diff --git a/pkg/sentry/mm/syscalls.go b/pkg/sentry/mm/syscalls.go
index daaae4da1..383703ec3 100644
--- a/pkg/sentry/mm/syscalls.go
+++ b/pkg/sentry/mm/syscalls.go
@@ -20,6 +20,7 @@ import (
"gvisor.googlesource.com/gvisor/pkg/abi/linux"
"gvisor.googlesource.com/gvisor/pkg/sentry/context"
+ "gvisor.googlesource.com/gvisor/pkg/sentry/kernel/auth"
"gvisor.googlesource.com/gvisor/pkg/sentry/kernel/futex"
"gvisor.googlesource.com/gvisor/pkg/sentry/limits"
"gvisor.googlesource.com/gvisor/pkg/sentry/memmap"
@@ -128,16 +129,24 @@ func (mm *MemoryManager) MMap(ctx context.Context, opts memmap.MMapOpts) (userme
// Get the new vma.
mm.mappingMu.Lock()
+ if opts.MLockMode < mm.defMLockMode {
+ opts.MLockMode = mm.defMLockMode
+ }
vseg, ar, err := mm.createVMALocked(ctx, opts)
if err != nil {
mm.mappingMu.Unlock()
return 0, err
}
+ // TODO: In Linux, VM_LOCKONFAULT (which may be set on the new
+ // vma by mlockall(MCL_FUTURE|MCL_ONFAULT) => mm_struct::def_flags) appears
+ // to effectively disable MAP_POPULATE by unsetting FOLL_POPULATE in
+ // mm/util.c:vm_mmap_pgoff() => mm/gup.c:__mm_populate() =>
+ // populate_vma_page_range(). Confirm this behavior.
switch {
- case opts.Precommit:
+ case opts.Precommit || opts.MLockMode == memmap.MLockEager:
// Get pmas and map with precommit as requested.
- mm.populateAndUnlock(ctx, vseg, ar, true)
+ mm.populateVMAAndUnlock(ctx, vseg, ar, true)
case opts.Mappable == nil && length <= privateAllocUnit:
// NOTE: Get pmas and map eagerly in the hope
@@ -146,7 +155,7 @@ func (mm *MemoryManager) MMap(ctx context.Context, opts memmap.MMapOpts) (userme
// memmap.Mappable.Translate is unknown; and only for small mappings,
// to avoid needing to allocate large amounts of memory that we may
// subsequently need to checkpoint.
- mm.populateAndUnlock(ctx, vseg, ar, false)
+ mm.populateVMAAndUnlock(ctx, vseg, ar, false)
default:
mm.mappingMu.Unlock()
@@ -155,31 +164,29 @@ func (mm *MemoryManager) MMap(ctx context.Context, opts memmap.MMapOpts) (userme
return ar.Start, nil
}
-// Preconditions: mm.mappingMu must be locked for writing.
+// populateVMA obtains pmas for addresses in ar in the given vma, and maps them
+// into mm.as if it is active.
//
-// Postconditions: mm.mappingMu will be unlocked.
-func (mm *MemoryManager) populateAndUnlock(ctx context.Context, vseg vmaIterator, ar usermem.AddrRange, precommit bool) {
+// Preconditions: mm.mappingMu must be locked. vseg.Range().IsSupersetOf(ar).
+func (mm *MemoryManager) populateVMA(ctx context.Context, vseg vmaIterator, ar usermem.AddrRange, precommit bool) {
if !vseg.ValuePtr().effectivePerms.Any() {
// Linux doesn't populate inaccessible pages. See
// mm/gup.c:populate_vma_page_range.
- mm.mappingMu.Unlock()
return
}
mm.activeMu.Lock()
+ // Can't defer mm.activeMu.Unlock(); see below.
- // Even if we get a new pma, we can't actually map it if we don't have an
+ // Even if we get new pmas, we can't actually map them if we don't have an
// AddressSpace.
if mm.as == nil {
mm.activeMu.Unlock()
- mm.mappingMu.Unlock()
return
}
// Ensure that we have usable pmas.
- mm.mappingMu.DowngradeLock()
pseg, _, err := mm.getPMAsLocked(ctx, vseg, ar, pmaOpts{})
- mm.mappingMu.RUnlock()
if err != nil {
// mm/util.c:vm_mmap_pgoff() ignores the error, if any, from
// mm/gup.c:mm_populate(). If it matters, we'll get it again when
@@ -197,6 +204,45 @@ func (mm *MemoryManager) populateAndUnlock(ctx context.Context, vseg vmaIterator
mm.activeMu.RUnlock()
}
+// populateVMAAndUnlock is equivalent to populateVMA, but also unconditionally
+// unlocks mm.mappingMu. In cases where populateVMAAndUnlock is usable, it is
+// preferable to populateVMA since it unlocks mm.mappingMu before performing
+// expensive operations that don't require it to be locked.
+//
+// Preconditions: mm.mappingMu must be locked for writing.
+// vseg.Range().IsSupersetOf(ar).
+//
+// Postconditions: mm.mappingMu will be unlocked.
+func (mm *MemoryManager) populateVMAAndUnlock(ctx context.Context, vseg vmaIterator, ar usermem.AddrRange, precommit bool) {
+ // See populateVMA above for commentary.
+ if !vseg.ValuePtr().effectivePerms.Any() {
+ mm.mappingMu.Unlock()
+ return
+ }
+
+ mm.activeMu.Lock()
+
+ if mm.as == nil {
+ mm.activeMu.Unlock()
+ mm.mappingMu.Unlock()
+ return
+ }
+
+ // mm.mappingMu doesn't need to be write-locked for getPMAsLocked, and it
+ // isn't needed at all for mapASLocked.
+ mm.mappingMu.DowngradeLock()
+ pseg, _, err := mm.getPMAsLocked(ctx, vseg, ar, pmaOpts{})
+ mm.mappingMu.RUnlock()
+ if err != nil {
+ mm.activeMu.Unlock()
+ return
+ }
+
+ mm.activeMu.DowngradeLock()
+ mm.mapASLocked(pseg, ar, precommit)
+ mm.activeMu.RUnlock()
+}
+
// MapStack allocates the initial process stack.
func (mm *MemoryManager) MapStack(ctx context.Context) (usermem.AddrRange, error) {
// maxStackSize is the maximum supported process stack size in bytes.
@@ -236,6 +282,7 @@ func (mm *MemoryManager) MapStack(ctx context.Context) (usermem.AddrRange, error
MaxPerms: usermem.AnyAccess,
Private: true,
GrowsDown: true,
+ MLockMode: mm.defMLockMode,
Hint: "[stack]",
})
return ar, err
@@ -334,6 +381,19 @@ func (mm *MemoryManager) MRemap(ctx context.Context, oldAddr usermem.Addr, oldSi
// occupies at least part of the destination. Thus the NoMove case always
// fails and the MayMove case always falls back to copying.
+ if vma := vseg.ValuePtr(); newSize > oldSize && vma.mlockMode != memmap.MLockNone {
+ // Check against RLIMIT_MEMLOCK. Unlike mmap, mlock, and mlockall,
+ // mremap in Linux does not check mm/mlock.c:can_do_mlock() and
+ // therefore does not return EPERM if RLIMIT_MEMLOCK is 0 and
+ // !CAP_IPC_LOCK.
+ mlockLimit := limits.FromContext(ctx).Get(limits.MemoryLocked).Cur
+ if creds := auth.CredentialsFromContext(ctx); !creds.HasCapabilityIn(linux.CAP_IPC_LOCK, creds.UserNamespace.Root()) {
+ if newLockedAS := mm.lockedAS - oldSize + newSize; newLockedAS > mlockLimit {
+ return 0, syserror.EAGAIN
+ }
+ }
+ }
+
if opts.Move != MRemapMustMove {
// Handle no-ops and in-place shrinking. These cases don't care if
// [oldAddr, oldEnd) maps to a single vma, or is even mapped at all
@@ -360,7 +420,7 @@ func (mm *MemoryManager) MRemap(ctx context.Context, oldAddr usermem.Addr, oldSi
if vma.mappable != nil {
newOffset = vseg.mappableRange().End
}
- _, _, err := mm.createVMALocked(ctx, memmap.MMapOpts{
+ vseg, ar, err := mm.createVMALocked(ctx, memmap.MMapOpts{
Length: newSize - oldSize,
MappingIdentity: vma.id,
Mappable: vma.mappable,
@@ -371,9 +431,13 @@ func (mm *MemoryManager) MRemap(ctx context.Context, oldAddr usermem.Addr, oldSi
MaxPerms: vma.maxPerms,
Private: vma.private,
GrowsDown: vma.growsDown,
+ MLockMode: vma.mlockMode,
Hint: vma.hint,
})
if err == nil {
+ if vma.mlockMode == memmap.MLockEager {
+ mm.populateVMA(ctx, vseg, ar, true)
+ }
return oldAddr, nil
}
// In-place growth failed. In the MRemapMayMove case, fall through to
@@ -462,8 +526,14 @@ func (mm *MemoryManager) MRemap(ctx context.Context, oldAddr usermem.Addr, oldSi
if vma.id != nil {
vma.id.IncRef()
}
- mm.vmas.Add(newAR, vma)
+ vseg := mm.vmas.Insert(mm.vmas.FindGap(newAR.Start), newAR, vma)
mm.usageAS += uint64(newAR.Length())
+ if vma.mlockMode != memmap.MLockNone {
+ mm.lockedAS += uint64(newAR.Length())
+ if vma.mlockMode == memmap.MLockEager {
+ mm.populateVMA(ctx, vseg, newAR, true)
+ }
+ }
return newAR.Start, nil
}
@@ -485,8 +555,11 @@ func (mm *MemoryManager) MRemap(ctx context.Context, oldAddr usermem.Addr, oldSi
vseg = mm.vmas.Isolate(vseg, oldAR)
vma := vseg.Value()
mm.vmas.Remove(vseg)
- mm.vmas.Add(newAR, vma)
+ vseg = mm.vmas.Insert(mm.vmas.FindGap(newAR.Start), newAR, vma)
mm.usageAS = mm.usageAS - uint64(oldAR.Length()) + uint64(newAR.Length())
+ if vma.mlockMode != memmap.MLockNone {
+ mm.lockedAS = mm.lockedAS - uint64(oldAR.Length()) + uint64(newAR.Length())
+ }
// Move pmas. This is technically optional for non-private pmas, which
// could just go through memmap.Mappable.Translate again, but it's required
@@ -501,6 +574,10 @@ func (mm *MemoryManager) MRemap(ctx context.Context, oldAddr usermem.Addr, oldSi
vma.mappable.RemoveMapping(ctx, mm, oldAR, vma.off, vma.isMappableAsWritable())
}
+ if vma.mlockMode == memmap.MLockEager {
+ mm.populateVMA(ctx, vseg, newAR, true)
+ }
+
return newAR.Start, nil
}
@@ -611,9 +688,10 @@ func (mm *MemoryManager) BrkSetup(ctx context.Context, addr usermem.Addr) {
// error on failure.
func (mm *MemoryManager) Brk(ctx context.Context, addr usermem.Addr) (usermem.Addr, error) {
mm.mappingMu.Lock()
- defer mm.mappingMu.Unlock()
+ // Can't defer mm.mappingMu.Unlock(); see below.
if addr < mm.brk.Start {
+ mm.mappingMu.Unlock()
return mm.brk.End, syserror.EINVAL
}
@@ -623,21 +701,24 @@ func (mm *MemoryManager) Brk(ctx context.Context, addr usermem.Addr) (usermem.Ad
// heap + data + bss. The segment sizes need to be plumbed from the
// loader package to fully enforce RLIMIT_DATA.
if uint64(addr-mm.brk.Start) > limits.FromContext(ctx).Get(limits.Data).Cur {
+ mm.mappingMu.Unlock()
return mm.brk.End, syserror.ENOMEM
}
oldbrkpg, _ := mm.brk.End.RoundUp()
newbrkpg, ok := addr.RoundUp()
if !ok {
+ mm.mappingMu.Unlock()
return mm.brk.End, syserror.EFAULT
}
switch {
case newbrkpg < oldbrkpg:
mm.unmapLocked(ctx, usermem.AddrRange{newbrkpg, oldbrkpg})
+ mm.mappingMu.Unlock()
case oldbrkpg < newbrkpg:
- _, _, err := mm.createVMALocked(ctx, memmap.MMapOpts{
+ vseg, ar, err := mm.createVMALocked(ctx, memmap.MMapOpts{
Length: uint64(newbrkpg - oldbrkpg),
Addr: oldbrkpg,
Fixed: true,
@@ -646,17 +727,221 @@ func (mm *MemoryManager) Brk(ctx context.Context, addr usermem.Addr) (usermem.Ad
Perms: usermem.ReadWrite,
MaxPerms: usermem.AnyAccess,
Private: true,
- Hint: "[heap]",
+ // Linux: mm/mmap.c:sys_brk() => do_brk_flags() includes
+ // mm->def_flags.
+ MLockMode: mm.defMLockMode,
+ Hint: "[heap]",
})
if err != nil {
+ mm.mappingMu.Unlock()
return mm.brk.End, err
}
+ if mm.defMLockMode == memmap.MLockEager {
+ mm.populateVMAAndUnlock(ctx, vseg, ar, true)
+ } else {
+ mm.mappingMu.Unlock()
+ }
+
+ default:
+ // Nothing to do.
+ mm.mappingMu.Unlock()
}
mm.brk.End = addr
return addr, nil
}
+// MLock implements the semantics of Linux's mlock()/mlock2()/munlock(),
+// depending on mode.
+func (mm *MemoryManager) MLock(ctx context.Context, addr usermem.Addr, length uint64, mode memmap.MLockMode) error {
+ // Linux allows this to overflow.
+ la, _ := usermem.Addr(length + addr.PageOffset()).RoundUp()
+ ar, ok := addr.RoundDown().ToRange(uint64(la))
+ if !ok {
+ return syserror.EINVAL
+ }
+
+ mm.mappingMu.Lock()
+ // Can't defer mm.mappingMu.Unlock(); see below.
+
+ if mode != memmap.MLockNone {
+ // Check against RLIMIT_MEMLOCK.
+ if creds := auth.CredentialsFromContext(ctx); !creds.HasCapabilityIn(linux.CAP_IPC_LOCK, creds.UserNamespace.Root()) {
+ mlockLimit := limits.FromContext(ctx).Get(limits.MemoryLocked).Cur
+ if mlockLimit == 0 {
+ mm.mappingMu.Unlock()
+ return syserror.EPERM
+ }
+ if newLockedAS := mm.lockedAS + uint64(ar.Length()) - mm.mlockedBytesRangeLocked(ar); newLockedAS > mlockLimit {
+ mm.mappingMu.Unlock()
+ return syserror.ENOMEM
+ }
+ }
+ }
+
+ // Check this after RLIMIT_MEMLOCK for consistency with Linux.
+ if ar.Length() == 0 {
+ mm.mappingMu.Unlock()
+ return nil
+ }
+
+ // Apply the new mlock mode to vmas.
+ var unmapped bool
+ vseg := mm.vmas.FindSegment(ar.Start)
+ for {
+ if !vseg.Ok() {
+ unmapped = true
+ break
+ }
+ vseg = mm.vmas.Isolate(vseg, ar)
+ vma := vseg.ValuePtr()
+ prevMode := vma.mlockMode
+ vma.mlockMode = mode
+ if mode != memmap.MLockNone && prevMode == memmap.MLockNone {
+ mm.lockedAS += uint64(vseg.Range().Length())
+ } else if mode == memmap.MLockNone && prevMode != memmap.MLockNone {
+ mm.lockedAS -= uint64(vseg.Range().Length())
+ }
+ if ar.End <= vseg.End() {
+ break
+ }
+ vseg, _ = vseg.NextNonEmpty()
+ }
+ mm.vmas.MergeRange(ar)
+ mm.vmas.MergeAdjacent(ar)
+ if unmapped {
+ mm.mappingMu.Unlock()
+ return syserror.ENOMEM
+ }
+
+ if mode == memmap.MLockEager {
+ // Ensure that we have usable pmas. Since we didn't return ENOMEM
+ // above, ar must be fully covered by vmas, so we can just use
+ // NextSegment below.
+ mm.activeMu.Lock()
+ mm.mappingMu.DowngradeLock()
+ for vseg := mm.vmas.FindSegment(ar.Start); vseg.Ok() && vseg.Start() < ar.End; vseg = vseg.NextSegment() {
+ if !vseg.ValuePtr().effectivePerms.Any() {
+ // Linux: mm/gup.c:__get_user_pages() returns EFAULT in this
+ // case, which is converted to ENOMEM by mlock.
+ mm.activeMu.Unlock()
+ mm.mappingMu.RUnlock()
+ return syserror.ENOMEM
+ }
+ _, _, err := mm.getPMAsLocked(ctx, vseg, vseg.Range().Intersect(ar), pmaOpts{})
+ if err != nil {
+ mm.activeMu.Unlock()
+ mm.mappingMu.RUnlock()
+ // Linux: mm/mlock.c:__mlock_posix_error_return()
+ if err == syserror.EFAULT {
+ return syserror.ENOMEM
+ }
+ if err == syserror.ENOMEM {
+ return syserror.EAGAIN
+ }
+ return err
+ }
+ }
+
+ // Map pmas into the active AddressSpace, if we have one.
+ mm.mappingMu.RUnlock()
+ if mm.as != nil {
+ mm.activeMu.DowngradeLock()
+ err := mm.mapASLocked(mm.pmas.LowerBoundSegment(ar.Start), ar, true /* precommit */)
+ mm.activeMu.RUnlock()
+ if err != nil {
+ return err
+ }
+ } else {
+ mm.activeMu.Unlock()
+ }
+ } else {
+ mm.mappingMu.Unlock()
+ }
+
+ return nil
+}
+
+// MLockAllOpts holds options to MLockAll.
+type MLockAllOpts struct {
+ // If Current is true, change the memory-locking behavior of all mappings
+ // to Mode. If Future is true, upgrade the memory-locking behavior of all
+ // future mappings to Mode. At least one of Current or Future must be true.
+ Current bool
+ Future bool
+ Mode memmap.MLockMode
+}
+
+// MLockAll implements the semantics of Linux's mlockall()/munlockall(),
+// depending on opts.
+func (mm *MemoryManager) MLockAll(ctx context.Context, opts MLockAllOpts) error {
+ if !opts.Current && !opts.Future {
+ return syserror.EINVAL
+ }
+
+ mm.mappingMu.Lock()
+ // Can't defer mm.mappingMu.Unlock(); see below.
+
+ if opts.Current {
+ if opts.Mode != memmap.MLockNone {
+ // Check against RLIMIT_MEMLOCK.
+ if creds := auth.CredentialsFromContext(ctx); !creds.HasCapabilityIn(linux.CAP_IPC_LOCK, creds.UserNamespace.Root()) {
+ mlockLimit := limits.FromContext(ctx).Get(limits.MemoryLocked).Cur
+ if mlockLimit == 0 {
+ mm.mappingMu.Unlock()
+ return syserror.EPERM
+ }
+ if uint64(mm.vmas.Span()) > mlockLimit {
+ mm.mappingMu.Unlock()
+ return syserror.ENOMEM
+ }
+ }
+ }
+ for vseg := mm.vmas.FirstSegment(); vseg.Ok(); vseg = vseg.NextSegment() {
+ vma := vseg.ValuePtr()
+ prevMode := vma.mlockMode
+ vma.mlockMode = opts.Mode
+ if opts.Mode != memmap.MLockNone && prevMode == memmap.MLockNone {
+ mm.lockedAS += uint64(vseg.Range().Length())
+ } else if opts.Mode == memmap.MLockNone && prevMode != memmap.MLockNone {
+ mm.lockedAS -= uint64(vseg.Range().Length())
+ }
+ }
+ }
+
+ if opts.Future {
+ mm.defMLockMode = opts.Mode
+ }
+
+ if opts.Current && opts.Mode == memmap.MLockEager {
+ // Linux: mm/mlock.c:sys_mlockall() => include/linux/mm.h:mm_populate()
+ // ignores the return value of __mm_populate(), so all errors below are
+ // ignored.
+ //
+ // Try to get usable pmas.
+ mm.activeMu.Lock()
+ mm.mappingMu.DowngradeLock()
+ for vseg := mm.vmas.FirstSegment(); vseg.Ok(); vseg = vseg.NextSegment() {
+ if vseg.ValuePtr().effectivePerms.Any() {
+ mm.getPMAsLocked(ctx, vseg, vseg.Range(), pmaOpts{})
+ }
+ }
+
+ // Map all pmas into the active AddressSpace, if we have one.
+ mm.mappingMu.RUnlock()
+ if mm.as != nil {
+ mm.activeMu.DowngradeLock()
+ mm.mapASLocked(mm.pmas.FirstSegment(), mm.applicationAddrRange(), true /* precommit */)
+ mm.activeMu.RUnlock()
+ } else {
+ mm.activeMu.Unlock()
+ }
+ } else {
+ mm.mappingMu.Unlock()
+ }
+ return nil
+}
+
// Decommit implements the semantics of Linux's madvise(MADV_DONTNEED).
func (mm *MemoryManager) Decommit(addr usermem.Addr, length uint64) error {
ar, ok := addr.ToRange(length)
@@ -680,46 +965,49 @@ func (mm *MemoryManager) Decommit(addr usermem.Addr, length uint64) error {
// ensures that Decommit immediately reduces host memory usage.
var didUnmapAS bool
pseg := mm.pmas.LowerBoundSegment(ar.Start)
- vseg := mm.vmas.LowerBoundSegment(ar.Start)
mem := mm.p.Memory()
- for pseg.Ok() && pseg.Start() < ar.End {
- pma := pseg.ValuePtr()
- if pma.private && !mm.isPMACopyOnWriteLocked(pseg) {
- psegAR := pseg.Range().Intersect(ar)
- vseg = vseg.seekNextLowerBound(psegAR.Start)
- if checkInvariants {
- if !vseg.Ok() {
- panic(fmt.Sprintf("no vma after %#x", psegAR.Start))
- }
- if psegAR.Start < vseg.Start() {
- panic(fmt.Sprintf("no vma in [%#x, %#x)", psegAR.Start, vseg.Start()))
- }
+ for vseg := mm.vmas.LowerBoundSegment(ar.Start); vseg.Ok() && vseg.Start() < ar.End; vseg = vseg.NextSegment() {
+ vma := vseg.ValuePtr()
+ if vma.mlockMode != memmap.MLockNone {
+ return syserror.EINVAL
+ }
+ vsegAR := vseg.Range().Intersect(ar)
+ // pseg should already correspond to either this vma or a later one,
+ // since there can't be a pma without a corresponding vma.
+ if checkInvariants {
+ if pseg.Ok() && pseg.End() <= vsegAR.Start {
+ panic(fmt.Sprintf("pma %v precedes vma %v", pseg.Range(), vsegAR))
}
- if vseg.Range().IsSupersetOf(psegAR) && vseg.ValuePtr().mappable == nil {
- if err := mem.Decommit(pseg.fileRangeOf(psegAR)); err == nil {
- pseg = pseg.NextSegment()
- continue
+ }
+ for pseg.Ok() && pseg.Start() < vsegAR.End {
+ pma := pseg.ValuePtr()
+ if pma.private && !mm.isPMACopyOnWriteLocked(pseg) {
+ psegAR := pseg.Range().Intersect(ar)
+ if vsegAR.IsSupersetOf(psegAR) && vma.mappable == nil {
+ if err := mem.Decommit(pseg.fileRangeOf(psegAR)); err == nil {
+ pseg = pseg.NextSegment()
+ continue
+ }
+ // If an error occurs, fall through to the general
+ // invalidation case below.
}
- // If an error occurs, fall through to the general
- // invalidation case below.
}
+ pseg = mm.pmas.Isolate(pseg, vsegAR)
+ pma = pseg.ValuePtr()
+ if !didUnmapAS {
+ // Unmap all of ar, not just pseg.Range(), to minimize host
+ // syscalls. AddressSpace mappings must be removed before
+ // mm.decPrivateRef().
+ mm.unmapASLocked(ar)
+ didUnmapAS = true
+ }
+ if pma.private {
+ mm.decPrivateRef(pseg.fileRange())
+ }
+ pma.file.DecRef(pseg.fileRange())
+ mm.removeRSSLocked(pseg.Range())
+ pseg = mm.pmas.Remove(pseg).NextSegment()
}
- pseg = mm.pmas.Isolate(pseg, ar)
- pma = pseg.ValuePtr()
- if !didUnmapAS {
- // Unmap all of ar, not just pseg.Range(), to minimize host
- // syscalls. AddressSpace mappings must be removed before
- // mm.decPrivateRef().
- mm.unmapASLocked(ar)
- didUnmapAS = true
- }
- if pma.private {
- mm.decPrivateRef(pseg.fileRange())
- }
- pma.file.DecRef(pseg.fileRange())
- mm.removeRSSLocked(pseg.Range())
-
- pseg = mm.pmas.Remove(pseg).NextSegment()
}
// "If there are some parts of the specified address space that are not
@@ -732,9 +1020,28 @@ func (mm *MemoryManager) Decommit(addr usermem.Addr, length uint64) error {
return nil
}
-// Sync implements the semantics of Linux's msync(MS_SYNC).
-func (mm *MemoryManager) Sync(ctx context.Context, addr usermem.Addr, length uint64) error {
- ar, ok := addr.ToRange(length)
+// MSyncOpts holds options to MSync.
+type MSyncOpts struct {
+ // Sync has the semantics of MS_SYNC.
+ Sync bool
+
+ // Invalidate has the semantics of MS_INVALIDATE.
+ Invalidate bool
+}
+
+// MSync implements the semantics of Linux's msync().
+func (mm *MemoryManager) MSync(ctx context.Context, addr usermem.Addr, length uint64, opts MSyncOpts) error {
+ if addr != addr.RoundDown() {
+ return syserror.EINVAL
+ }
+ if length == 0 {
+ return nil
+ }
+ la, ok := usermem.Addr(length).RoundUp()
+ if !ok {
+ return syserror.ENOMEM
+ }
+ ar, ok := addr.ToRange(uint64(la))
if !ok {
return syserror.ENOMEM
}
@@ -759,10 +1066,14 @@ func (mm *MemoryManager) Sync(ctx context.Context, addr usermem.Addr, length uin
}
lastEnd = vseg.End()
vma := vseg.ValuePtr()
+ if opts.Invalidate && vma.mlockMode != memmap.MLockNone {
+ mm.mappingMu.RUnlock()
+ return syserror.EBUSY
+ }
// It's only possible to have dirtied the Mappable through a shared
// mapping. Don't check if the mapping is writable, because mprotect
// may have changed this, and also because Linux doesn't.
- if id := vma.id; id != nil && vma.mappable != nil && !vma.private {
+ if id := vma.id; opts.Sync && id != nil && vma.mappable != nil && !vma.private {
// We can't call memmap.MappingIdentity.Msync while holding
// mm.mappingMu since it may take fs locks that precede it in the
// lock order.
diff --git a/pkg/sentry/mm/vma.go b/pkg/sentry/mm/vma.go
index 5c2c802f6..28ba9f2f5 100644
--- a/pkg/sentry/mm/vma.go
+++ b/pkg/sentry/mm/vma.go
@@ -17,8 +17,10 @@ package mm
import (
"fmt"
+ "gvisor.googlesource.com/gvisor/pkg/abi/linux"
"gvisor.googlesource.com/gvisor/pkg/sentry/arch"
"gvisor.googlesource.com/gvisor/pkg/sentry/context"
+ "gvisor.googlesource.com/gvisor/pkg/sentry/kernel/auth"
"gvisor.googlesource.com/gvisor/pkg/sentry/limits"
"gvisor.googlesource.com/gvisor/pkg/sentry/memmap"
"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
@@ -53,6 +55,23 @@ func (mm *MemoryManager) createVMALocked(ctx context.Context, opts memmap.MMapOp
return vmaIterator{}, usermem.AddrRange{}, syserror.ENOMEM
}
+ if opts.MLockMode != memmap.MLockNone {
+ // Check against RLIMIT_MEMLOCK.
+ if creds := auth.CredentialsFromContext(ctx); !creds.HasCapabilityIn(linux.CAP_IPC_LOCK, creds.UserNamespace.Root()) {
+ mlockLimit := limits.FromContext(ctx).Get(limits.MemoryLocked).Cur
+ if mlockLimit == 0 {
+ return vmaIterator{}, usermem.AddrRange{}, syserror.EPERM
+ }
+ newLockedAS := mm.lockedAS + opts.Length
+ if opts.Unmap {
+ newLockedAS -= mm.mlockedBytesRangeLocked(ar)
+ }
+ if newLockedAS > mlockLimit {
+ return vmaIterator{}, usermem.AddrRange{}, syserror.EAGAIN
+ }
+ }
+ }
+
// Remove overwritten mappings. This ordering is consistent with Linux:
// compare Linux's mm/mmap.c:mmap_region() => do_munmap(),
// file->f_op->mmap().
@@ -85,10 +104,14 @@ func (mm *MemoryManager) createVMALocked(ctx context.Context, opts memmap.MMapOp
maxPerms: opts.MaxPerms,
private: opts.Private,
growsDown: opts.GrowsDown,
+ mlockMode: opts.MLockMode,
id: opts.MappingIdentity,
hint: opts.Hint,
})
mm.usageAS += opts.Length
+ if opts.MLockMode != memmap.MLockNone {
+ mm.lockedAS += opts.Length
+ }
return vseg, ar, nil
}
@@ -201,6 +224,17 @@ func (mm *MemoryManager) findHighestAvailableLocked(length, alignment uint64, bo
return 0, syserror.ENOMEM
}
+// Preconditions: mm.mappingMu must be locked.
+func (mm *MemoryManager) mlockedBytesRangeLocked(ar usermem.AddrRange) uint64 {
+ var total uint64
+ for vseg := mm.vmas.LowerBoundSegment(ar.Start); vseg.Ok() && vseg.Start() < ar.End; vseg = vseg.NextSegment() {
+ if vseg.ValuePtr().mlockMode != memmap.MLockNone {
+ total += uint64(vseg.Range().Intersect(ar).Length())
+ }
+ }
+ return total
+}
+
// getVMAsLocked ensures that vmas exist for all addresses in ar, and support
// access of type (at, ignorePermissions). It returns:
//
@@ -338,6 +372,9 @@ func (mm *MemoryManager) removeVMAsLocked(ctx context.Context, ar usermem.AddrRa
vma.id.DecRef()
}
mm.usageAS -= uint64(vmaAR.Length())
+ if vma.mlockMode != memmap.MLockNone {
+ mm.lockedAS -= uint64(vmaAR.Length())
+ }
vgap = mm.vmas.Remove(vseg)
vseg = vgap.NextSegment()
}
@@ -368,6 +405,7 @@ func (vmaSetFunctions) Merge(ar1 usermem.AddrRange, vma1 vma, ar2 usermem.AddrRa
vma1.maxPerms != vma2.maxPerms ||
vma1.private != vma2.private ||
vma1.growsDown != vma2.growsDown ||
+ vma1.mlockMode != vma2.mlockMode ||
vma1.id != vma2.id ||
vma1.hint != vma2.hint {
return vma{}, false
diff --git a/pkg/sentry/syscalls/linux/linux64.go b/pkg/sentry/syscalls/linux/linux64.go
index 2aab948da..cc5ebb955 100644
--- a/pkg/sentry/syscalls/linux/linux64.go
+++ b/pkg/sentry/syscalls/linux/linux64.go
@@ -196,11 +196,11 @@ var AMD64 = &kernel.SyscallTable{
145: SchedGetscheduler,
146: SchedGetPriorityMax,
147: SchedGetPriorityMin,
- 148: syscalls.ErrorWithEvent(syscall.EPERM), // SchedRrGetInterval,
- 149: syscalls.Error(nil), // Mlock, TODO
- 150: syscalls.Error(nil), // Munlock, TODO
- 151: syscalls.Error(nil), // Mlockall, TODO
- 152: syscalls.Error(nil), // Munlockall, TODO
+ 148: syscalls.ErrorWithEvent(syscall.EPERM), // SchedRrGetInterval,
+ 149: Mlock,
+ 150: Munlock,
+ 151: Mlockall,
+ 152: Munlockall,
153: syscalls.CapError(linux.CAP_SYS_TTY_CONFIG), // Vhangup,
154: syscalls.Error(syscall.EPERM), // ModifyLdt,
155: syscalls.Error(syscall.EPERM), // PivotRoot,
@@ -373,8 +373,9 @@ var AMD64 = &kernel.SyscallTable{
// 322: Execveat, TODO
// 323: Userfaultfd, TODO
// 324: Membarrier, TODO
- // Syscalls after 325 are backports from 4.6.
- 325: syscalls.Error(nil), // Mlock2, TODO
+ 325: Mlock2,
+ // Syscalls after 325 are "backports" from versions of Linux after 4.4.
+ // 326: CopyFileRange,
327: Preadv2,
// 328: Pwritev2, // Pwritev2, TODO
},
diff --git a/pkg/sentry/syscalls/linux/sys_mmap.go b/pkg/sentry/syscalls/linux/sys_mmap.go
index 145f7846c..8732861e0 100644
--- a/pkg/sentry/syscalls/linux/sys_mmap.go
+++ b/pkg/sentry/syscalls/linux/sys_mmap.go
@@ -69,6 +69,9 @@ func Mmap(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallC
GrowsDown: linux.MAP_GROWSDOWN&flags != 0,
Precommit: linux.MAP_POPULATE&flags != 0,
}
+ if linux.MAP_LOCKED&flags != 0 {
+ opts.MLockMode = memmap.MLockEager
+ }
defer func() {
if opts.MappingIdentity != nil {
opts.MappingIdentity.DecRef()
@@ -384,16 +387,6 @@ func Msync(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
length := args[1].SizeT()
flags := args[2].Int()
- if addr != addr.RoundDown() {
- return 0, nil, syserror.EINVAL
- }
- if length == 0 {
- return 0, nil, nil
- }
- la, ok := usermem.Addr(length).RoundUp()
- if !ok {
- return 0, nil, syserror.ENOMEM
- }
// "The flags argument should specify exactly one of MS_ASYNC and MS_SYNC,
// and may additionally include the MS_INVALIDATE bit. ... However, Linux
// permits a call to msync() that specifies neither of these flags, with
@@ -406,39 +399,72 @@ func Msync(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
if sync && flags&linux.MS_ASYNC != 0 {
return 0, nil, syserror.EINVAL
}
+ err := t.MemoryManager().MSync(t, addr, uint64(length), mm.MSyncOpts{
+ Sync: sync,
+ Invalidate: flags&linux.MS_INVALIDATE != 0,
+ })
+ // MSync calls fsync, the same interrupt conversion rules apply, see
+ // mm/msync.c, fsync POSIX.1-2008.
+ return 0, nil, syserror.ConvertIntr(err, kernel.ERESTARTSYS)
+}
+
+// Mlock implements linux syscall mlock(2).
+func Mlock(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ addr := args[0].Pointer()
+ length := args[1].SizeT()
+
+ return 0, nil, t.MemoryManager().MLock(t, addr, uint64(length), memmap.MLockEager)
+}
- // MS_INVALIDATE "asks to invalidate other mappings of the same file (so
- // that they can be updated with the fresh values just written)". This is a
- // no-op given that shared memory exists. However, MS_INVALIDATE can also
- // be used to detect mlocks: "EBUSY: MS_INVALIDATE was specified in flags,
- // and a memory lock exists for the specified address range." Given that
- // mlock is stubbed out, it's unsafe to pass MS_INVALIDATE silently since
- // some user program could be using it for synchronization.
- if flags&linux.MS_INVALIDATE != 0 {
+// Mlock2 implements linux syscall mlock2(2).
+func Mlock2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ addr := args[0].Pointer()
+ length := args[1].SizeT()
+ flags := args[2].Int()
+
+ if flags&^(linux.MLOCK_ONFAULT) != 0 {
return 0, nil, syserror.EINVAL
}
- // MS_SYNC "requests an update and waits for it to complete."
- if sync {
- err := t.MemoryManager().Sync(t, addr, uint64(la))
- // Sync calls fsync, the same interrupt conversion rules apply, see
- // mm/msync.c, fsync POSIX.1-2008.
- return 0, nil, syserror.ConvertIntr(err, kernel.ERESTARTSYS)
- }
- // MS_ASYNC "specifies that an update be scheduled, but the call returns
- // immediately". As long as dirty pages are tracked and eventually written
- // back, this is a no-op. (Correspondingly: "Since Linux 2.6.19, MS_ASYNC
- // is in fact a no-op, since the kernel properly tracks dirty pages and
- // flushes them to storage as necessary.")
- //
- // However: "ENOMEM: The indicated memory (or part of it) was not mapped."
- // This applies even for MS_ASYNC.
- ar, ok := addr.ToRange(uint64(la))
- if !ok {
- return 0, nil, syserror.ENOMEM
+
+ mode := memmap.MLockEager
+ if flags&linux.MLOCK_ONFAULT != 0 {
+ mode = memmap.MLockLazy
}
- mapped := t.MemoryManager().VirtualMemorySizeRange(ar)
- if mapped != uint64(la) {
- return 0, nil, syserror.ENOMEM
+ return 0, nil, t.MemoryManager().MLock(t, addr, uint64(length), mode)
+}
+
+// Munlock implements linux syscall munlock(2).
+func Munlock(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ addr := args[0].Pointer()
+ length := args[1].SizeT()
+
+ return 0, nil, t.MemoryManager().MLock(t, addr, uint64(length), memmap.MLockNone)
+}
+
+// Mlockall implements linux syscall mlockall(2).
+func Mlockall(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ flags := args[0].Int()
+
+ if flags&^(linux.MCL_CURRENT|linux.MCL_FUTURE|linux.MCL_ONFAULT) != 0 {
+ return 0, nil, syserror.EINVAL
}
- return 0, nil, nil
+
+ mode := memmap.MLockEager
+ if flags&linux.MCL_ONFAULT != 0 {
+ mode = memmap.MLockLazy
+ }
+ return 0, nil, t.MemoryManager().MLockAll(t, mm.MLockAllOpts{
+ Current: flags&linux.MCL_CURRENT != 0,
+ Future: flags&linux.MCL_FUTURE != 0,
+ Mode: mode,
+ })
+}
+
+// Munlockall implements linux syscall munlockall(2).
+func Munlockall(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ return 0, nil, t.MemoryManager().MLockAll(t, mm.MLockAllOpts{
+ Current: true,
+ Future: true,
+ Mode: memmap.MLockNone,
+ })
}
diff --git a/pkg/sentry/syscalls/linux/sys_rlimit.go b/pkg/sentry/syscalls/linux/sys_rlimit.go
index 2f16e1791..b0b216045 100644
--- a/pkg/sentry/syscalls/linux/sys_rlimit.go
+++ b/pkg/sentry/syscalls/linux/sys_rlimit.go
@@ -90,6 +90,7 @@ var setableLimits = map[limits.LimitType]struct{}{
limits.CPU: {},
limits.Data: {},
limits.FileSize: {},
+ limits.MemoryLocked: {},
limits.Stack: {},
// These are not enforced, but we include them here to avoid returning
// EPERM, since some apps expect them to succeed.
diff --git a/runsc/boot/limits.go b/runsc/boot/limits.go
index 8ecda6d0e..e3e716bf9 100644
--- a/runsc/boot/limits.go
+++ b/runsc/boot/limits.go
@@ -29,7 +29,7 @@ var fromLinuxResource = map[string]limits.LimitType{
"RLIMIT_DATA": limits.Data,
"RLIMIT_FSIZE": limits.FileSize,
"RLIMIT_LOCKS": limits.Locks,
- "RLIMIT_MEMLOCK": limits.MemoryPagesLocked,
+ "RLIMIT_MEMLOCK": limits.MemoryLocked,
"RLIMIT_MSGQUEUE": limits.MessageQueueBytes,
"RLIMIT_NICE": limits.Nice,
"RLIMIT_NOFILE": limits.NumberOfFiles,
@@ -55,7 +55,7 @@ func createLimitSet(spec *specs.Spec) (*limits.LimitSet, error) {
ls.SetUnchecked(limits.Data, limits.Limit{Cur: limits.Infinity, Max: limits.Infinity})
ls.SetUnchecked(limits.FileSize, limits.Limit{Cur: limits.Infinity, Max: limits.Infinity})
ls.SetUnchecked(limits.Locks, limits.Limit{Cur: limits.Infinity, Max: limits.Infinity})
- ls.SetUnchecked(limits.MemoryPagesLocked, limits.Limit{Cur: 65536, Max: 65536})
+ ls.SetUnchecked(limits.MemoryLocked, limits.Limit{Cur: 65536, Max: 65536})
ls.SetUnchecked(limits.MessageQueueBytes, limits.Limit{Cur: 819200, Max: 819200})
ls.SetUnchecked(limits.Nice, limits.Limit{Cur: 0, Max: 0})
ls.SetUnchecked(limits.NumberOfFiles, limits.Limit{Cur: 1048576, Max: 1048576})
diff --git a/test/syscalls/linux/BUILD b/test/syscalls/linux/BUILD
index 784997c18..aca55f492 100644
--- a/test/syscalls/linux/BUILD
+++ b/test/syscalls/linux/BUILD
@@ -1020,6 +1020,21 @@ cc_binary(
)
cc_binary(
+ name = "mlock_test",
+ testonly = 1,
+ srcs = ["mlock.cc"],
+ linkstatic = 1,
+ deps = [
+ "//test/util:capability_util",
+ "//test/util:cleanup",
+ "//test/util:memory_util",
+ "//test/util:multiprocess_util",
+ "//test/util:test_util",
+ "@com_google_googletest//:gtest",
+ ],
+)
+
+cc_binary(
name = "mmap_test",
testonly = 1,
srcs = ["mmap.cc"],
diff --git a/test/syscalls/linux/mlock.cc b/test/syscalls/linux/mlock.cc
new file mode 100644
index 000000000..a0d876c2e
--- /dev/null
+++ b/test/syscalls/linux/mlock.cc
@@ -0,0 +1,344 @@
+// Copyright 2018 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <errno.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/resource.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+#include "test/util/capability_util.h"
+#include "test/util/cleanup.h"
+#include "test/util/memory_util.h"
+#include "test/util/multiprocess_util.h"
+#include "test/util/test_util.h"
+
+using ::testing::_;
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+PosixErrorOr<bool> CanMlock() {
+ struct rlimit rlim;
+ if (getrlimit(RLIMIT_MEMLOCK, &rlim) < 0) {
+ return PosixError(errno, "getrlimit(RLIMIT_MEMLOCK)");
+ }
+ if (rlim.rlim_cur != 0) {
+ return true;
+ }
+ return HaveCapability(CAP_IPC_LOCK);
+}
+
+// Returns true if the page containing addr is mlocked.
+bool IsPageMlocked(uintptr_t addr) {
+ // This relies on msync(MS_INVALIDATE) interacting correctly with mlocked
+ // pages, which is tested for by the MsyncInvalidate case below.
+ int const rv = msync(reinterpret_cast<void*>(addr & ~(kPageSize - 1)),
+ kPageSize, MS_ASYNC | MS_INVALIDATE);
+ if (rv == 0) {
+ return false;
+ }
+ // This uses TEST_PCHECK_MSG since it's used in subprocesses.
+ TEST_PCHECK_MSG(errno == EBUSY, "msync failed with unexpected errno");
+ return true;
+}
+
+PosixErrorOr<Cleanup> ScopedSetSoftRlimit(int resource, rlim_t newval) {
+ struct rlimit old_rlim;
+ if (getrlimit(resource, &old_rlim) != 0) {
+ return PosixError(errno, "getrlimit failed");
+ }
+ struct rlimit new_rlim = old_rlim;
+ new_rlim.rlim_cur = newval;
+ if (setrlimit(resource, &new_rlim) != 0) {
+ return PosixError(errno, "setrlimit failed");
+ }
+ return Cleanup([resource, old_rlim] {
+ TEST_PCHECK(setrlimit(resource, &old_rlim) == 0);
+ });
+}
+
+TEST(MlockTest, Basic) {
+ SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(CanMlock()));
+ auto const mapping = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE));
+ EXPECT_FALSE(IsPageMlocked(mapping.addr()));
+ ASSERT_THAT(mlock(mapping.ptr(), mapping.len()), SyscallSucceeds());
+ EXPECT_TRUE(IsPageMlocked(mapping.addr()));
+}
+
+TEST(MlockTest, ProtNone) {
+ SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(CanMlock()));
+ auto const mapping =
+ ASSERT_NO_ERRNO_AND_VALUE(MmapAnon(kPageSize, PROT_NONE, MAP_PRIVATE));
+ EXPECT_FALSE(IsPageMlocked(mapping.addr()));
+ ASSERT_THAT(mlock(mapping.ptr(), mapping.len()),
+ SyscallFailsWithErrno(ENOMEM));
+ // ENOMEM is returned because mlock can't populate the page, but it's still
+ // considered locked.
+ EXPECT_TRUE(IsPageMlocked(mapping.addr()));
+}
+
+TEST(MlockTest, MadviseDontneed) {
+ SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(CanMlock()));
+ auto const mapping = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE));
+ ASSERT_THAT(mlock(mapping.ptr(), mapping.len()), SyscallSucceeds());
+ EXPECT_THAT(madvise(mapping.ptr(), mapping.len(), MADV_DONTNEED),
+ SyscallFailsWithErrno(EINVAL));
+}
+
+TEST(MlockTest, MsyncInvalidate) {
+ SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(CanMlock()));
+ auto const mapping = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE));
+ ASSERT_THAT(mlock(mapping.ptr(), mapping.len()), SyscallSucceeds());
+ EXPECT_THAT(msync(mapping.ptr(), mapping.len(), MS_ASYNC | MS_INVALIDATE),
+ SyscallFailsWithErrno(EBUSY));
+ EXPECT_THAT(msync(mapping.ptr(), mapping.len(), MS_SYNC | MS_INVALIDATE),
+ SyscallFailsWithErrno(EBUSY));
+}
+
+TEST(MlockTest, Fork) {
+ SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(CanMlock()));
+ auto const mapping = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE));
+ EXPECT_FALSE(IsPageMlocked(mapping.addr()));
+ ASSERT_THAT(mlock(mapping.ptr(), mapping.len()), SyscallSucceeds());
+ EXPECT_TRUE(IsPageMlocked(mapping.addr()));
+ EXPECT_THAT(
+ InForkedProcess([&] { TEST_CHECK(!IsPageMlocked(mapping.addr())); }),
+ IsPosixErrorOkAndHolds(0));
+}
+
+TEST(MlockTest, RlimitMemlockZero) {
+ if (ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_IPC_LOCK))) {
+ ASSERT_NO_ERRNO(SetCapability(CAP_IPC_LOCK, false));
+ }
+ Cleanup reset_rlimit =
+ ASSERT_NO_ERRNO_AND_VALUE(ScopedSetSoftRlimit(RLIMIT_MEMLOCK, 0));
+ auto const mapping = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE));
+ EXPECT_FALSE(IsPageMlocked(mapping.addr()));
+ ASSERT_THAT(mlock(mapping.ptr(), mapping.len()),
+ SyscallFailsWithErrno(EPERM));
+}
+
+TEST(MlockTest, RlimitMemlockInsufficient) {
+ if (ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_IPC_LOCK))) {
+ ASSERT_NO_ERRNO(SetCapability(CAP_IPC_LOCK, false));
+ }
+ Cleanup reset_rlimit =
+ ASSERT_NO_ERRNO_AND_VALUE(ScopedSetSoftRlimit(RLIMIT_MEMLOCK, kPageSize));
+ auto const mapping = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(2 * kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE));
+ EXPECT_FALSE(IsPageMlocked(mapping.addr()));
+ ASSERT_THAT(mlock(mapping.ptr(), mapping.len()),
+ SyscallFailsWithErrno(ENOMEM));
+}
+
+TEST(MunlockTest, Basic) {
+ SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(CanMlock()));
+ auto const mapping = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE));
+ EXPECT_FALSE(IsPageMlocked(mapping.addr()));
+ ASSERT_THAT(mlock(mapping.ptr(), mapping.len()), SyscallSucceeds());
+ EXPECT_TRUE(IsPageMlocked(mapping.addr()));
+ ASSERT_THAT(munlock(mapping.ptr(), mapping.len()), SyscallSucceeds());
+ EXPECT_FALSE(IsPageMlocked(mapping.addr()));
+}
+
+TEST(MunlockTest, NotLocked) {
+ SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(CanMlock()));
+ auto const mapping = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE));
+ EXPECT_FALSE(IsPageMlocked(mapping.addr()));
+ EXPECT_THAT(munlock(mapping.ptr(), mapping.len()), SyscallSucceeds());
+ EXPECT_FALSE(IsPageMlocked(mapping.addr()));
+}
+
+// There is currently no test for mlockall(MCL_CURRENT) because the default
+// RLIMIT_MEMLOCK of 64 KB is insufficient to actually invoke
+// mlockall(MCL_CURRENT).
+
+TEST(MlockallTest, Future) {
+ SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(CanMlock()));
+
+ // Run this test in a separate (single-threaded) subprocess to ensure that a
+ // background thread doesn't try to mmap a large amount of memory, fail due
+ // to hitting RLIMIT_MEMLOCK, and explode the process violently.
+ EXPECT_THAT(InForkedProcess([] {
+ auto const mapping =
+ MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE)
+ .ValueOrDie();
+ TEST_CHECK(!IsPageMlocked(mapping.addr()));
+ TEST_PCHECK(mlockall(MCL_FUTURE) == 0);
+ // Ensure that mlockall(MCL_FUTURE) is turned off before the end
+ // of the test, as otherwise mmaps may fail unexpectedly.
+ Cleanup do_munlockall([] { TEST_PCHECK(munlockall() == 0); });
+ auto const mapping2 = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE));
+ TEST_CHECK(IsPageMlocked(mapping2.addr()));
+ // Fire munlockall() and check that it disables
+ // mlockall(MCL_FUTURE).
+ do_munlockall.Release()();
+ auto const mapping3 = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE));
+ TEST_CHECK(!IsPageMlocked(mapping2.addr()));
+ }),
+ IsPosixErrorOkAndHolds(0));
+}
+
+TEST(MunlockallTest, Basic) {
+ SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(CanMlock()));
+ auto const mapping = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_LOCKED));
+ EXPECT_TRUE(IsPageMlocked(mapping.addr()));
+ ASSERT_THAT(munlockall(), SyscallSucceeds());
+ EXPECT_FALSE(IsPageMlocked(mapping.addr()));
+}
+
+#ifndef SYS_mlock2
+#ifdef __x86_64__
+#define SYS_mlock2 325
+#endif
+#endif
+
+#ifndef MLOCK_ONFAULT
+#define MLOCK_ONFAULT 0x01 // Linux: include/uapi/asm-generic/mman-common.h
+#endif
+
+#ifdef SYS_mlock2
+
+int mlock2(void const* addr, size_t len, int flags) {
+ return syscall(SYS_mlock2, addr, len, flags);
+}
+
+TEST(Mlock2Test, NoFlags) {
+ SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(CanMlock()));
+ auto const mapping = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE));
+ EXPECT_FALSE(IsPageMlocked(mapping.addr()));
+ ASSERT_THAT(mlock2(mapping.ptr(), mapping.len(), 0), SyscallSucceeds());
+ EXPECT_TRUE(IsPageMlocked(mapping.addr()));
+}
+
+TEST(Mlock2Test, MlockOnfault) {
+ SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(CanMlock()));
+ auto const mapping = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE));
+ EXPECT_FALSE(IsPageMlocked(mapping.addr()));
+ ASSERT_THAT(mlock2(mapping.ptr(), mapping.len(), MLOCK_ONFAULT),
+ SyscallSucceeds());
+ EXPECT_TRUE(IsPageMlocked(mapping.addr()));
+}
+
+TEST(Mlock2Test, UnknownFlags) {
+ SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(CanMlock()));
+ auto const mapping = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE));
+ EXPECT_THAT(mlock2(mapping.ptr(), mapping.len(), ~0),
+ SyscallFailsWithErrno(EINVAL));
+}
+
+#endif // defined(SYS_mlock2)
+
+TEST(MapLockedTest, Basic) {
+ SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(CanMlock()));
+ auto const mapping = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_LOCKED));
+ EXPECT_TRUE(IsPageMlocked(mapping.addr()));
+ EXPECT_THAT(munlock(mapping.ptr(), mapping.len()), SyscallSucceeds());
+ EXPECT_FALSE(IsPageMlocked(mapping.addr()));
+}
+
+TEST(MapLockedTest, RlimitMemlockZero) {
+ if (ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_IPC_LOCK))) {
+ ASSERT_NO_ERRNO(SetCapability(CAP_IPC_LOCK, false));
+ }
+ Cleanup reset_rlimit =
+ ASSERT_NO_ERRNO_AND_VALUE(ScopedSetSoftRlimit(RLIMIT_MEMLOCK, 0));
+ EXPECT_THAT(
+ MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_LOCKED),
+ PosixErrorIs(EPERM, _));
+}
+
+TEST(MapLockedTest, RlimitMemlockInsufficient) {
+ if (ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_IPC_LOCK))) {
+ ASSERT_NO_ERRNO(SetCapability(CAP_IPC_LOCK, false));
+ }
+ Cleanup reset_rlimit =
+ ASSERT_NO_ERRNO_AND_VALUE(ScopedSetSoftRlimit(RLIMIT_MEMLOCK, kPageSize));
+ EXPECT_THAT(
+ MmapAnon(2 * kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_LOCKED),
+ PosixErrorIs(EAGAIN, _));
+}
+
+TEST(MremapLockedTest, Basic) {
+ SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(CanMlock()));
+ auto mapping = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_LOCKED));
+ EXPECT_TRUE(IsPageMlocked(mapping.addr()));
+
+ void* addr = mremap(mapping.ptr(), mapping.len(), 2 * mapping.len(),
+ MREMAP_MAYMOVE, nullptr);
+ if (addr == MAP_FAILED) {
+ FAIL() << "mremap failed: " << errno << " (" << strerror(errno) << ")";
+ }
+ mapping.release();
+ mapping.reset(addr, 2 * mapping.len());
+ EXPECT_TRUE(IsPageMlocked(reinterpret_cast<uintptr_t>(addr)));
+}
+
+TEST(MremapLockedTest, RlimitMemlockZero) {
+ SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(CanMlock()));
+ auto mapping = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_LOCKED));
+ EXPECT_TRUE(IsPageMlocked(mapping.addr()));
+
+ if (ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_IPC_LOCK))) {
+ ASSERT_NO_ERRNO(SetCapability(CAP_IPC_LOCK, false));
+ }
+ Cleanup reset_rlimit =
+ ASSERT_NO_ERRNO_AND_VALUE(ScopedSetSoftRlimit(RLIMIT_MEMLOCK, 0));
+ void* addr = mremap(mapping.ptr(), mapping.len(), 2 * mapping.len(),
+ MREMAP_MAYMOVE, nullptr);
+ EXPECT_TRUE(addr == MAP_FAILED && errno == EAGAIN)
+ << "addr = " << addr << ", errno = " << errno;
+}
+
+TEST(MremapLockedTest, RlimitMemlockInsufficient) {
+ SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(CanMlock()));
+ auto mapping = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_LOCKED));
+ EXPECT_TRUE(IsPageMlocked(mapping.addr()));
+
+ if (ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_IPC_LOCK))) {
+ ASSERT_NO_ERRNO(SetCapability(CAP_IPC_LOCK, false));
+ }
+ Cleanup reset_rlimit = ASSERT_NO_ERRNO_AND_VALUE(
+ ScopedSetSoftRlimit(RLIMIT_MEMLOCK, mapping.len()));
+ void* addr = mremap(mapping.ptr(), mapping.len(), 2 * mapping.len(),
+ MREMAP_MAYMOVE, nullptr);
+ EXPECT_TRUE(addr == MAP_FAILED && errno == EAGAIN)
+ << "addr = " << addr << ", errno = " << errno;
+}
+
+} // namespace
+
+} // namespace testing
+} // namespace gvisor
diff --git a/test/syscalls/linux/msync.cc b/test/syscalls/linux/msync.cc
index 0ddc621aa..72d90dc78 100644
--- a/test/syscalls/linux/msync.cc
+++ b/test/syscalls/linux/msync.cc
@@ -43,14 +43,13 @@ class MsyncParameterizedTest : public ::testing::TestWithParam<MsyncTestParam> {
protected:
int msync_flags() const { return std::get<0>(GetParam()); }
- PosixErrorOr<Mapping> GetMapping() const {
- auto rv = std::get<1>(GetParam())();
- return rv;
- }
+ PosixErrorOr<Mapping> GetMapping() const { return std::get<1>(GetParam())(); }
};
-// All valid msync(2) flag combinations (not including MS_INVALIDATE, which
-// gVisor doesn't implement).
+// All valid msync(2) flag combinations, not including MS_INVALIDATE. ("Linux
+// permits a call to msync() that specifies neither [MS_SYNC or MS_ASYNC], with
+// semantics that are (currently) equivalent to specifying MS_ASYNC." -
+// msync(2))
constexpr std::initializer_list<int> kMsyncFlags = {MS_SYNC, MS_ASYNC, 0};
// Returns functions that return mappings that should be successfully
@@ -134,6 +133,15 @@ TEST_P(MsyncFullParamTest, UnalignedAddressFails) {
SyscallFailsWithErrno(EINVAL));
}
+TEST_P(MsyncFullParamTest, InvalidateUnlockedSucceeds) {
+ auto m = ASSERT_NO_ERRNO_AND_VALUE(GetMapping());
+ EXPECT_THAT(msync(m.ptr(), m.len(), msync_flags() | MS_INVALIDATE),
+ SyscallSucceeds());
+}
+
+// The test for MS_INVALIDATE on mlocked pages is in mlock.cc since it requires
+// probing for mlock support.
+
INSTANTIATE_TEST_CASE_P(
All, MsyncFullParamTest,
::testing::Combine(::testing::ValuesIn(kMsyncFlags),
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 20:42:57 +0000