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| author | Russ Cox <rsc@golang.org> | 2021-02-19 06:01:25 -0500 |
|---|---|---|
| committer | Russ Cox <rsc@golang.org> | 2021-02-19 16:09:17 +0000 |
| commit | 02e5a8fdfcc8e237f5b55618ccbe9ad845014427 (patch) | |
| tree | 111de57074d94e075524e2c824a091c849940a3e /src/runtime/traceback.go | |
| parent | fa18f224c378f5831210077944e5df718efb8df5 (diff) | |
| download | go-02e5a8fdfcc8e237f5b55618ccbe9ad845014427.tar.gz go-02e5a8fdfcc8e237f5b55618ccbe9ad845014427.zip | |
runtime: ignore SPWRITE in syscall functions
netbsd/amd64's Syscall9 changes SP using ADD and SUB,
which are treated as SPWRITEs (they are not accounted for
in the sp-adjust tracking, and there are too many functions that
would report mismatched stack adjustments at RET if they were).
A traceback starting in Syscall9 as saved by entersyscall complains
about the SPWRITE-ness unnecessarily, since the PC/SP are saved
at the start of the function. Ignore SPWRITE in that case.
netbsd/arm's Syscall6 also changes SP (R13), using a direct write.
So even if we could handle the ADD/SUB in the amd64 case or
rewrote that assembly, we'd still be stuck with a more difficult
problem in this case. Ignoring the SPWRITE fixes it.
Example crashes:
https://build.golang.org/log/160fc7b051a2cf90782b75a99984fff129329e66
https://build.golang.org/log/7879e2fecdb400eee616294285e1f952e5b17301
Change-Id: I0c8e9696066e90dafed6d4a93d11697da23f0080
Reviewed-on: https://go-review.googlesource.com/c/go/+/294072
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Diffstat (limited to 'src/runtime/traceback.go')
| -rw-r--r-- | src/runtime/traceback.go | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/src/runtime/traceback.go b/src/runtime/traceback.go index eb185eecd36..53eb6898482 100644 --- a/src/runtime/traceback.go +++ b/src/runtime/traceback.go @@ -174,6 +174,12 @@ func gentraceback(pc0, sp0, lr0 uintptr, gp *g, skip int, pcbuf *uintptr, max in // So we don't need to exclude it with the other SP-writing functions. flag &^= funcFlag_SPWRITE } + if frame.pc == pc0 && frame.sp == sp0 && pc0 == gp.syscallpc && sp0 == gp.syscallsp { + // Some Syscall functions write to SP, but they do so only after + // saving the entry PC/SP using entersyscall. + // Since we are using the entry PC/SP, the later SP write doesn't matter. + flag &^= funcFlag_SPWRITE + } // Found an actual function. // Derive frame pointer and link register. |