From a2a64769d0d3cc0380b4b6ecdcb781a2f790a69e Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Thu, 9 Jun 2005 12:29:00 -0700 Subject: [PATCH] [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 Signed-off-by: Tony Luck --- arch/ia64/kernel/fsys.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/ia64/kernel/fsys.S b/arch/ia64/kernel/fsys.S index 4f3cdef7579..962b6c4e32b 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 -- 2.20.1