author | Shawn Walker-Salas <shawn.walker@oracle.com> |
Thu, 14 Apr 2016 12:48:37 -0700 | |
changeset 5781 | ecbdf40c0a37 |
parent 5331 | 9c955076ffe3 |
permissions | -rw-r--r-- |
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From 6b26788c55d2c1e874e6321b8ce33f1a2c0270e6 Mon Sep 17 00:00:00 2001 |
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From: Austin Clements <[email protected]> |
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Date: Mon, 23 Nov 2015 15:03:38 -0500 |
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Subject: [PATCH 62/63] [release-branch.go1.5] runtime: take stack barrier lock |
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during copystack |
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Commit bbd1a1c prevented SIGPROF from scanning stacks that were being |
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copied, but it didn't prevent a stack copy (specifically a stack |
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shrink) from happening while SIGPROF is scanning the stack. As a |
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result, a stack copy may adjust stack barriers while SIGPROF is in the |
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middle of scanning a stack, causing SIGPROF to panic when it detects |
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an inconsistent stack barrier. |
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Fix this by taking the stack barrier lock while adjusting the stack. |
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In addition to preventing SIGPROF from scanning this stack, this will |
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block until any in-progress SIGPROF is done scanning the stack. |
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For 1.5.2. |
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Fixes #13362. |
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Updates #12932. |
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Change-Id: I422219c363054410dfa56381f7b917e04690e5dd |
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Reviewed-on: https://go-review.googlesource.com/17191 |
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Run-TryBot: Austin Clements <[email protected]> |
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Reviewed-by: Russ Cox <[email protected]> |
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Run-TryBot: Russ Cox <[email protected]> |
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TryBot-Result: Gobot Gobot <[email protected]> |
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Reviewed-on: https://go-review.googlesource.com/17194 |
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--- |
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src/runtime/stack1.go | 6 ++++++ |
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1 file changed, 6 insertions(+) |
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diff --git a/src/runtime/stack1.go b/src/runtime/stack1.go |
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index efcb5f2..19634ef 100644 |
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--- a/src/runtime/stack1.go |
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+++ b/src/runtime/stack1.go |
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@@ -609,6 +609,10 @@ func copystack(gp *g, newsize uintptr) { |
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print("copystack gp=", gp, " [", hex(old.lo), " ", hex(old.hi-used), " ", hex(old.hi), "]/", gp.stackAlloc, " -> [", hex(new.lo), " ", hex(new.hi-used), " ", hex(new.hi), "]/", newsize, "\n") |
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} |
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+ // Disallow sigprof scans of this stack and block if there's |
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+ // one in progress. |
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+ gcLockStackBarriers(gp) |
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+ |
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// adjust pointers in the to-be-copied frames |
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var adjinfo adjustinfo |
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adjinfo.old = old |
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@@ -640,6 +644,8 @@ func copystack(gp *g, newsize uintptr) { |
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gp.stackAlloc = newsize |
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gp.stkbar = newstkbar |
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+ gcUnlockStackBarriers(gp) |
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+ |
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// free old stack |
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if stackPoisonCopy != 0 { |
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fillstack(old, 0xfc) |
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-- |
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2.6.1 |
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