diff options
| author | Christoph Lameter <clameter@sgi.com> | 2005-06-09 12:29:00 -0700 |
|---|---|---|
| committer | Tony Luck <tony.luck@intel.com> | 2005-06-09 13:04:30 -0700 |
| commit | a2a64769d0d3cc0380b4b6ecdcb781a2f790a69e (patch) | |
| tree | 387ee93cf8ee39ca64dd53380d1ea25a4f6134e7 /arch/ia64/kernel/fsys.S | |
| parent | 1834cd9fd27763f4e55184e4138a19ba36620174 (diff) | |
[IA64] Fix race condition in the rt_sigprocmask fastcall
current->blocked will be set to the value of current->thread_info->flags if the
cmpxchg to update thread_info->flags fails. For performance reasons the store into
current->blocked was placed in the cmpxchg loop. However, the cmpxchg overwrites the
register holding the value to be stored. In the rare case of a retry the value of
thread_info->flags will be written into current->blocked.
The fix is to use another register so that the register containing the current->blocked
value is not overwritten.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64/kernel/fsys.S')
| -rw-r--r-- | arch/ia64/kernel/fsys.S | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/ia64/kernel/fsys.S b/arch/ia64/kernel/fsys.S index 4f3cdef75797..962b6c4e32b5 100644 --- a/arch/ia64/kernel/fsys.S +++ b/arch/ia64/kernel/fsys.S @@ -460,9 +460,9 @@ EX(.fail_efault, ld8 r14=[r33]) // r14 <- *set ;; st8 [r2]=r14 // update current->blocked with new mask - cmpxchg4.acq r14=[r9],r18,ar.ccv // current->thread_info->flags <- r18 + cmpxchg4.acq r8=[r9],r18,ar.ccv // current->thread_info->flags <- r18 ;; - cmp.ne p6,p0=r17,r14 // update failed? + cmp.ne p6,p0=r17,r8 // update failed? (p6) br.cond.spnt.few 1b // yes -> retry #ifdef CONFIG_SMP |