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| author | Chris Metcalf <cmetcalf@ezchip.com> | 2015-07-21 12:04:52 -0400 |
|---|---|---|
| committer | Chris Metcalf <cmetcalf@ezchip.com> | 2015-07-21 12:11:55 -0400 |
| commit | 0ac4f1dab3e5778c79994a89111b4eb1d247ab12 (patch) | |
| tree | bcc24bc8dd8a2c2b879e38a1c97234d9fcf420ba /sysdeps/unix/sysv/linux/tile/setcontext.S | |
| parent | f30d94a74a30b832354d4b87c23a4909ed24b929 (diff) | |
| download | glibc-0ac4f1dab3e5778c79994a89111b4eb1d247ab12.tar glibc-0ac4f1dab3e5778c79994a89111b4eb1d247ab12.tar.gz glibc-0ac4f1dab3e5778c79994a89111b4eb1d247ab12.tar.bz2 glibc-0ac4f1dab3e5778c79994a89111b4eb1d247ab12.zip | |
tile: Fix BZ #18508 (makecontext yield infinite backtrace)
It turns out tile suffered from the same problem as S390. However,
disabling CFI information for the __startcontext on tile was not
sufficient to fix the problem; I think the backtracer will just
blindly try to follow the link register (lr) in that case.
Instead, the change adds a cfi_undefined directive for "lr"
and then arranges to call __startcontext directly when the new
context starts, rather than just synthesizing a return to it.
In addition to being a bit easier now to understand the control
flow, this also allows the cfi_undefined directive to be placed in
a way that causes it to be in force at the address that the "lr"
from the called function points to.
Diffstat (limited to 'sysdeps/unix/sysv/linux/tile/setcontext.S')
| -rw-r--r-- | sysdeps/unix/sysv/linux/tile/setcontext.S | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/tile/setcontext.S b/sysdeps/unix/sysv/linux/tile/setcontext.S index ee9edbefe1..02d6a1578c 100644 --- a/sysdeps/unix/sysv/linux/tile/setcontext.S +++ b/sysdeps/unix/sysv/linux/tile/setcontext.S @@ -190,7 +190,9 @@ END (__setcontext) weak_alias (__setcontext, setcontext) ENTRY (__startcontext) + cfi_undefined (lr) FEEDBACK_ENTER(__startcontext) + jalr r31 BEQZ r30, 1f { move r0, r30 |