* [COMMITTED 2.23] mips: terminate the FDE before the return trampoline in makecontext
@ 2016-01-01 0:00 Aurelien Jarno
0 siblings, 0 replies; only message in thread
From: Aurelien Jarno @ 2016-01-01 0:00 UTC (permalink / raw)
To: libc-stable; +Cc: Aurelien Jarno
In makecontext the FDE needs to be terminated before the return
trampoline otherwise backtrace called within a context created by
makecontext yields infinite backtrace.
This bug has been present for a long time, stdlib/tst-makecontext did
not fail until recent commit e535ce25. Tested on mips-linux-gnu and
mips64el-linux-gnuabi64 and mips-linux-gnu, no regression.
This fixes stdlib/tst-makecontext on MIPS.
Changelog:
[BZ #19792]
* sysdeps/unix/sysv/linux/mips/makecontext.S (__makecontext):
Terminate FDE before return label.
(cherry picked from commit f8e9c4d30c28b8815e65a391416e8b15d2e7cbb8)
---
ChangeLog | 6 ++++++
NEWS | 1 +
sysdeps/unix/sysv/linux/mips/makecontext.S | 7 +++++++
3 files changed, 14 insertions(+)
diff --git a/ChangeLog b/ChangeLog
index 3177332..559f860 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2016-03-09 Aurelien Jarno <aurelien@aurel32.net>
+
+ [BZ #19792]
+ * sysdeps/unix/sysv/linux/mips/makecontext.S (__makecontext):
+ Terminate FDE before return label.
+
2016-03-08 Aurelien Jarno <aurelien@aurel32.net>
* include/sys/auxv.h: New file.
diff --git a/NEWS b/NEWS
index 509e336..987f5f5 100644
--- a/NEWS
+++ b/NEWS
@@ -14,6 +14,7 @@ Security related changes:
The following bugs are resolved with this release:
[19679] gcc-4.9.3 C++ exception handling broken due to unaligned stack
+ [19792] MIPS: backtrace yields infinite backtrace with makecontext
\f
Version 2.23
diff --git a/sysdeps/unix/sysv/linux/mips/makecontext.S b/sysdeps/unix/sysv/linux/mips/makecontext.S
index 66600c7..3196554 100644
--- a/sysdeps/unix/sysv/linux/mips/makecontext.S
+++ b/sysdeps/unix/sysv/linux/mips/makecontext.S
@@ -153,6 +153,11 @@ NESTED (__makecontext, FRAMESZ, ra)
#endif
jr ra
+ /* We need to terminate the FDE to stop unwinding if backtrace was
+ called within a context created by makecontext. */
+ cfi_endproc
+ nop
+
99:
#ifdef __PIC__
move gp, s1
@@ -186,6 +191,8 @@ NESTED (__makecontext, FRAMESZ, ra)
1:
lb zero, (zero)
b 1b
+
+ cfi_startproc
PSEUDO_END (__makecontext)
weak_alias (__makecontext, makecontext)
--
2.7.0
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