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| author | Keith Randall <keithr@alum.mit.edu> | 2018-09-11 15:14:28 -0700 |
|---|---|---|
| committer | Keith Randall <khr@golang.org> | 2018-10-03 19:54:23 +0000 |
| commit | 9dac0a8132d7db5225b27bdd8faeb3158e624159 (patch) | |
| tree | f2d0d9f80bc5f7101fc06c1d13d719fbd663533b /src/runtime/runtime2.go | |
| parent | 9a8372f8bd5a39d2476bfa9247407b51f9193b9e (diff) | |
| download | go-git-9dac0a8132d7db5225b27bdd8faeb3158e624159.tar.gz | |
runtime: on a signal, set traceback address to a deferreturn call
When a function triggers a signal (like a segfault which translates to
a nil pointer exception) during execution, a sigpanic handler is just
below it on the stack. The function itself did not stop at a
safepoint, so we have to figure out what safepoint we should use to
scan its stack frame.
Previously we used the site of the most recent defer to get the live
variables at the signal site. That answer is not quite correct, as
explained in #27518. Instead, use the site of a deferreturn call.
It has all the right variables marked as live (no args, all the return
values, except those that escape to the heap, in which case the
corresponding PAUTOHEAP variables will be live instead).
This CL requires stack objects, so that all the local variables
and args referenced by the deferred closures keep the right variables alive.
Fixes #27518
Change-Id: Id45d8a8666759986c203181090b962e2981e48ca
Reviewed-on: https://go-review.googlesource.com/c/134637
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Diffstat (limited to 'src/runtime/runtime2.go')
| -rw-r--r-- | src/runtime/runtime2.go | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go index 2f009abdbb..bbb66bb8fa 100644 --- a/src/runtime/runtime2.go +++ b/src/runtime/runtime2.go @@ -650,14 +650,16 @@ type _func struct { entry uintptr // start pc nameoff int32 // function name - args int32 // in/out args size - funcID funcID // set for certain special runtime functions + args int32 // in/out args size + deferreturn uint32 // offset of a deferreturn block from entry, if any. pcsp int32 pcfile int32 pcln int32 npcdata int32 - nfuncdata int32 + funcID funcID // set for certain special runtime functions + _ [2]int8 // unused + nfuncdata uint8 // must be last } // layout of Itab known to compilers |