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| author | Waldemar Brodkorb <wbx@uclibc-ng.org> | 2018-03-09 19:14:40 +0100 |
|---|---|---|
| committer | Waldemar Brodkorb <wbx@uclibc-ng.org> | 2018-03-09 19:14:40 +0100 |
| commit | 6e627523ee4b3fc00c30dcff74c2adf93e2b6840 (patch) | |
| tree | 42940ad77a0fd14bd029fa2ee0e912a9a4ef45ac /libc/sysdeps/linux/sparc | |
| parent | 01e9f2f202a0afc658bfd82c0ff1770de7900bb1 (diff) | |
sparc32: Add nop before __startcontext to stop unwinding
From glibc commit 9aa5c222b9e0409143410a02b6364a3b25dbf028
[BZ #22919]
Diffstat (limited to 'libc/sysdeps/linux/sparc')
| -rw-r--r-- | libc/sysdeps/linux/sparc/setcontext.S | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/sparc/setcontext.S b/libc/sysdeps/linux/sparc/setcontext.S index f9da21563..48ab5f719 100644 --- a/libc/sysdeps/linux/sparc/setcontext.S +++ b/libc/sysdeps/linux/sparc/setcontext.S @@ -95,6 +95,19 @@ END(__setcontext) weak_alias (__setcontext, setcontext) +/* We add an NOP here to separate between __setcontext/__startcontext. The + wanted behavior that happens is: when unwinding from a function called + inside a makecontext() context, FDE lookup will use '&__startcontext - 1', + then returns NULL for no FDE found, and immediately ends the unwind, in + a normal fashion. + + If this NOP word does not exist, FDE lookup just repeatedly finds + __setcontext's FDE in an infinite loop, due to the convention of using + 'address - 1' for FDE lookup. Modifiying/deleting the below + __startcontext's FDE has no help on this. */ + + nop + /* This is the helper code which gets called if a function which is registered with 'makecontext' returns. In this case we have to install the context listed in the uc_link element of the context |