Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=c0a79b229ac0e3a96fc00d5be65a498ceb06ef63
Commit: c0a79b229ac0e3a96fc00d5be65a498ceb06ef63
Parent: 63abdcdc021063bf1cfcddfd3c1a14a761539807
Author: Mathieu Desnoyers <[EMAIL PROTECTED]>
AuthorDate: Sat Mar 10 00:19:49 2007 -0800
Committer: David S. Miller <[EMAIL PROTECTED]>
CommitDate: Sat Mar 10 00:19:49 2007 -0800
[SPARC64]: Fix atomicity of TIF update in flush_thread()
Fix atomicity of TIF update in flush_thread() for sparc64
Fixes correctly the race by using *_ti_thread_flag.
Race :
parent process executing :
sys_ptrace()
(lock_kernel())
(ptrace_get_task_struct(pid))
arch_ptrace()
ptrace_detach()
ptrace_disable(child);
clear_singlestep(child);
clear_tsk_thread_flag(child, TIF_SINGLESTEP);
(which clears the TIF_SINGLESTEP flag atomically from a different
process)
(put_task_struct(child))
(unlock_kernel())
And at the same time, in the child process :
sys_execve()
do_execve()
search_binary_handler()
load_elf_binary()
flush_old_exec()
flush_thread()
doing a non-atomic thread flag update
Signed-off-by: Mathieu Desnoyers <[EMAIL PROTECTED]>
Signed-off-by: David S. Miller <[EMAIL PROTECTED]>
---
arch/sparc64/kernel/process.c | 9 +++++++--
1 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/arch/sparc64/kernel/process.c b/arch/sparc64/kernel/process.c
index 7d75cd4..b291060 100644
--- a/arch/sparc64/kernel/process.c
+++ b/arch/sparc64/kernel/process.c
@@ -413,8 +413,13 @@ void flush_thread(void)
struct thread_info *t = current_thread_info();
struct mm_struct *mm;
- if (t->flags & _TIF_ABI_PENDING)
- t->flags ^= (_TIF_ABI_PENDING | _TIF_32BIT);
+ if (test_ti_thread_flag(t, TIF_ABI_PENDING)) {
+ clear_ti_thread_flag(t, TIF_ABI_PENDING);
+ if (test_ti_thread_flag(t, TIF_32BIT))
+ clear_ti_thread_flag(t, TIF_32BIT);
+ else
+ set_ti_thread_flag(t, TIF_32BIT);
+ }
mm = t->task->mm;
if (mm)
-
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