Age | Commit message (Collapse) | Author |
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In the general case, files may have offsets between MaxInt64 and MaxUint64; in
Linux pgoff is consistently represented by an unsigned long, and in gVisor the
offset types in memmap.MappableRange are uint64. However, regular file mmap is
constrained to int64 offsets (on 64-bit systems) by
mm/mmap.c:file_mmap_size_max() => MAX_LFS_FILESIZE == LLONG_MAX.
As a related fix, check for chunkStart overflow in fsutil.HostFileMapper; chunk
offsets are uint64s, but as noted above some file types may use uint64 offsets
beyond MaxInt64.
Reported-by: syzbot+71342a1585aed97ed9f7@syzkaller.appspotmail.com
PiperOrigin-RevId: 397136751
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PiperOrigin-RevId: 393841270
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Document this ordering in mm/mm.go.
PiperOrigin-RevId: 393413203
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We cannot hold mm.aioManager.mu while calling MUnmap, because MUnmap attempts
to aquire mm.mappingMu. This violates the lock order as documented in mm/mm.go.
PiperOrigin-RevId: 392102472
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Removes package syserror and moves still relevant code to either linuxerr
or to syserr (to be later removed).
Internal errors are converted from random types to *errors.Error types used
in linuxerr. Internal errors are in linuxerr/internal.go.
PiperOrigin-RevId: 390724202
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Convert remaining public errors (e.g. EINTR) from syserror to linuxerr.
PiperOrigin-RevId: 390471763
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Update the following from syserror to the linuxerr equivalent:
EEXIST
EFAULT
ENOTDIR
ENOTTY
EOPNOTSUPP
ERANGE
ESRCH
PiperOrigin-RevId: 384329869
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This change makes the checklocks analyzer considerable more powerful, adding:
* The ability to traverse complex structures, e.g. to have multiple nested
fields as part of the annotation.
* The ability to resolve simple anonymous functions and closures, and perform
lock analysis across these invocations. This does not apply to closures that
are passed elsewhere, since it is not possible to know the context in which
they might be invoked.
* The ability to annotate return values in addition to receivers and other
parameters, with the same complex structures noted above.
* Ignoring locking semantics for "fresh" objects, i.e. objects that are
allocated in the local frame (typically a new-style function).
* Sanity checking of locking state across block transitions and returns, to
ensure that no unexpected locks are held.
Note that initially, most of these findings are excluded by a comprehensive
nogo.yaml. The findings that are included are fundamental lock violations.
The changes here should be relatively low risk, minor refactorings to either
include necessary annotations to simplify the code structure (in general
removing closures in favor of methods) so that the analyzer can be easily
track the lock state.
This change additional includes two changes to nogo itself:
* Sanity checking of all types to ensure that the binary and ast-derived
types have a consistent objectpath, to prevent the bug above from occurring
silently (and causing much confusion). This also requires a trick in
order to ensure that serialized facts are consumable downstream. This can
be removed with https://go-review.googlesource.com/c/tools/+/331789 merged.
* A minor refactoring to isolation the objdump settings in its own package.
This was originally used to implement the sanity check above, but this
information is now being passed another way. The minor refactor is preserved
however, since it cleans up the code slightly and is minimal risk.
PiperOrigin-RevId: 382613300
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Update/remove most syserror errors to linuxerr equivalents. For list
of removed errors, see //pkg/syserror/syserror.go.
PiperOrigin-RevId: 382574582
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Update all instances of the above errors to the faster linuxerr implementation.
With the temporary linuxerr.Equals(), no logical changes are made.
PiperOrigin-RevId: 382306655
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Remove three syserror entries duplicated in linuxerr. Because of the
linuxerr.Equals method, this is a mere change of return values from
syserror to linuxerr definitions.
Done with only these three errnos as CLs removing all grow to a significantly
large size.
PiperOrigin-RevId: 382173835
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Add Equals method to compare syserror and unix.Errno errors to linuxerr errors.
This will facilitate removal of syserror definitions in a followup, and
finding needed conversions from unix.Errno to linuxerr.
PiperOrigin-RevId: 380909667
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Split usermem package to help remove syserror dependency in go_marshal.
New hostarch package contains code not dependent on syserror.
PiperOrigin-RevId: 365651233
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PiperOrigin-RevId: 353697719
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PiperOrigin-RevId: 352894106
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syzkaller reported the closing of a nil channel. This is only possible when the
AIOContext was destroyed twice.
Some scenarios that could lead to this:
- It died and then some called aioCtx.Prepare() on it and then killed it again
which could cause the double destroy. The context could have been destroyed
in between the call to LookupAIOContext() and Prepare().
- aioManager was destroyed but it did not update the contexts map. So
Lookup could still return a dead AIOContext and then someone could call
Prepare on it and kill it again.
So added a check in aioCtx.Prepare() for the context being dead. This will
prevent a dead context from resurrecting.
Also refactored code to destroy the aioContext consistently. Earlier we were not
munmapping the aioContexts that were destroyed upon aioManager destruction.
Reported-by: syzbot+ef6a588d0ce6059991d2@syzkaller.appspotmail.com
PiperOrigin-RevId: 347704347
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PiperOrigin-RevId: 347047550
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This lets us avoid treating a value of 0 as one reference. All references
using the refsvfs2 template must call InitRefs() before the reference is
incremented/decremented, or else a panic will occur. Therefore, it should be
pretty easy to identify missing InitRef calls during testing.
Updates #1486.
PiperOrigin-RevId: 341411151
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Our current reference leak checker uses finalizers to verify whether an object
has reached zero references before it is garbage collected. There are multiple
problems with this mechanism, so a rewrite is in order.
With finalizers, there is no way to guarantee that a finalizer will run before
the program exits. When an unreachable object with a finalizer is garbage
collected, its finalizer will be added to a queue and run asynchronously. The
best we can do is run garbage collection upon sandbox exit to make sure that
all finalizers are enqueued.
Furthermore, if there is a chain of finalized objects, e.g. A points to B
points to C, garbage collection needs to run multiple times before all of the
finalizers are enqueued. The first GC run will register the finalizer for A but
not free it. It takes another GC run to free A, at which point B's finalizer
can be registered. As a result, we need to run GC as many times as the length
of the longest such chain to have a somewhat reliable leak checker.
Finally, a cyclical chain of structs pointing to one another will never be
garbage collected if a finalizer is set. This is a well-known issue with Go
finalizers (https://github.com/golang/go/issues/7358). Using leak checking on
filesystem objects that produce cycles will not work and even result in memory
leaks.
The new leak checker stores reference counted objects in a global map when
leak check is enabled and removes them once they are destroyed. At sandbox
exit, any remaining objects in the map are considered as leaked. This provides
a deterministic way of detecting leaks without relying on the complexities of
finalizers and garbage collection.
This approach has several benefits over the former, including:
- Always detects leaks of objects that should be destroyed very close to
sandbox exit. The old checker very rarely detected these leaks, because it
relied on garbage collection to be run in a short window of time.
- Panics if we forgot to enable leak check on a ref-counted object (we will try
to remove it from the map when it is destroyed, but it will never have been
added).
- Can store extra logging information in the map values without adding to the
size of the ref count struct itself. With the size of just an int64, the ref
count object remains compact, meaning frequent operations like IncRef/DecRef
are more cache-efficient.
- Can aggregate leak results in a single report after the sandbox exits.
Instead of having warnings littered in the log, which were
non-deterministically triggered by garbage collection, we can print all
warning messages at once. Note that this could also be a limitation--the
sandbox must exit properly for leaks to be detected.
Some basic benchmarking indicates that this change does not significantly
affect performance when leak checking is enabled, which is understandable
since registering/unregistering is only done once for each filesystem object.
Updates #1486.
PiperOrigin-RevId: 338685972
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cf. 2a36ab717e8f "rseq/membarrier: Add MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ"
PiperOrigin-RevId: 336186795
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This change also adds support to go_stateify for detecting an appropriate
receiver name, avoiding a large number of false positives.
PiperOrigin-RevId: 335994587
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