* [tip:perf/urgent] x86/asm/traps: Disable tracing and kprobes in fixup_bad_iret and sync_regs
[not found] <50e33d26adca60816f3ba968875801652507d0c4.1416870125.git.luto@amacapital.net>
@ 2014-11-25 6:30 ` tip-bot for Andy Lutomirski
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From: tip-bot for Andy Lutomirski @ 2014-11-25 6:30 UTC (permalink / raw)
To: linux-tip-commits; +Cc: hpa, luto, linux-kernel, torvalds, rostedt, tglx, mingo
Commit-ID: 7ddc6a2199f1da405a2fb68c40db8899b1a8cd87
Gitweb: http://git.kernel.org/tip/7ddc6a2199f1da405a2fb68c40db8899b1a8cd87
Author: Andy Lutomirski <luto@amacapital.net>
AuthorDate: Mon, 24 Nov 2014 17:39:06 -0800
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 25 Nov 2014 07:26:55 +0100
x86/asm/traps: Disable tracing and kprobes in fixup_bad_iret and sync_regs
These functions can be executed on the int3 stack, so kprobes
are dangerous. Tracing is probably a bad idea, too.
Fixes: b645af2d5905 ("x86_64, traps: Rework bad_iret")
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: <stable@vger.kernel.org> # Backport as far back as it would apply
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/50e33d26adca60816f3ba968875801652507d0c4.1416870125.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/traps.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index de801f2..07ab8e9 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -387,7 +387,7 @@ NOKPROBE_SYMBOL(do_int3);
* for scheduling or signal handling. The actual stack switch is done in
* entry.S
*/
-asmlinkage __visible struct pt_regs *sync_regs(struct pt_regs *eregs)
+asmlinkage __visible notrace struct pt_regs *sync_regs(struct pt_regs *eregs)
{
struct pt_regs *regs = eregs;
/* Did already sync */
@@ -413,7 +413,7 @@ struct bad_iret_stack {
struct pt_regs regs;
};
-asmlinkage __visible
+asmlinkage __visible notrace
struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s)
{
/*
@@ -436,6 +436,7 @@ struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s)
BUG_ON(!user_mode_vm(&new_stack->regs));
return new_stack;
}
+NOKPROBE_SYMBOL(fixup_bad_iret);
#endif
/*
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