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authorPetr Tesarik <ptesarik@suse.cz>2007-12-12 15:23:34 +0100
committerTony Luck <tony.luck@intel.com>2008-02-08 12:01:18 -0800
commit3b2ce0b17824c42bc2e46f7dd903b4acf5e9fff9 (patch)
treeacf3913f8c0a479615060ffed4cec9283047761c /arch/ia64/kernel/process.c
parent5aa92ffda1b6244b4a248df0b95c07d183ab96d2 (diff)
[IA64] Synchronize kernel RSE to user-space and back
This is base kernel patch for ptrace RSE bug. It's basically a backport from the utrace RSE patch I sent out several weeks ago. please review. when a thread is stopped (ptraced), debugger might change thread's user stack (change memory directly), and we must avoid the RSE stored in kernel to override user stack (user space's RSE is newer than kernel's in the case). To workaround the issue, we copy kernel RSE to user RSE before the task is stopped, so user RSE has updated data. we then copy user RSE to kernel after the task is resummed from traced stop and kernel will use the newer RSE to return to user. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Petr Tesarik <ptesarik@suse.cz> CC: Roland McGrath <roland@redhat.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64/kernel/process.c')
-rw-r--r--arch/ia64/kernel/process.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 5c9efe62656..be6c6f7be02 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -163,6 +163,8 @@ void tsk_clear_notify_resume(struct task_struct *tsk)
if (tsk->thread.pfm_needs_checking)
return;
#endif
+ if (test_ti_thread_flag(task_thread_info(tsk), TIF_RESTORE_RSE))
+ return;
clear_ti_thread_flag(task_thread_info(tsk), TIF_NOTIFY_RESUME);
}
@@ -184,6 +186,10 @@ do_notify_resume_user (sigset_t *unused, struct sigscratch *scr, long in_syscall
/* deal with pending signal delivery */
if (test_thread_flag(TIF_SIGPENDING)||test_thread_flag(TIF_RESTORE_SIGMASK))
ia64_do_signal(scr, in_syscall);
+
+ /* copy user rbs to kernel rbs */
+ if (unlikely(test_thread_flag(TIF_RESTORE_RSE)))
+ ia64_sync_krbs();
}
static int pal_halt = 1;