On Mon, 2015-01-05 at 12:49 -0800, [email protected] wrote: > The patch below does not apply to the 3.10-stable tree. > If someone wants it applied there, or to any other stable or longterm > tree, then please email the backport, including the original git commit > id to <[email protected]>.
I've attached what I think is a sensible backport. Ben. > thanks, > > greg k-h > > ------------------ original commit in Linus's tree ------------------ > > From 7ddc6a2199f1da405a2fb68c40db8899b1a8cd87 Mon Sep 17 00:00:00 2001 > From: Andy Lutomirski <[email protected]> > Date: Mon, 24 Nov 2014 17:39:06 -0800 > Subject: [PATCH] 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 <[email protected]> > Cc: <[email protected]> # Backport as far back as it would apply > Cc: Linus Torvalds <[email protected]> > Cc: Steven Rostedt <[email protected]> > Link: > http://lkml.kernel.org/r/50e33d26adca60816f3ba968875801652507d0c4.1416870125.git.l...@amacapital.net > Signed-off-by: Ingo Molnar <[email protected]> > > diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c > index de801f22128a..07ab8e9733c5 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 > > /* -- Ben Hutchings The world is coming to an end. Please log off.
From 0b740af1a1697796b5a9a0b024b22b7e97e9bfd2 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski <[email protected]> Date: Mon, 24 Nov 2014 17:39:06 -0800 Subject: [PATCH] x86/asm/traps: Disable tracing and kprobes in fixup_bad_iret and sync_regs commit 7ddc6a2199f1da405a2fb68c40db8899b1a8cd87 upstream. 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 <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Steven Rostedt <[email protected]> Link: http://lkml.kernel.org/r/50e33d26adca60816f3ba968875801652507d0c4.1416870125.git.l...@amacapital.net Signed-off-by: Ingo Molnar <[email protected]> [bwh: Backported to 3.10: - Use __kprobes instead of NOKPROBE_SYMBOL() - Adjust context] Signed-off-by: Ben Hutchings <[email protected]> --- arch/x86/kernel/traps.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 332cafe..0010ed7 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -362,7 +362,7 @@ exit: * for scheduling or signal handling. The actual stack switch is done in * entry.S */ -asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs) +asmlinkage notrace __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs) { struct pt_regs *regs = eregs; /* Did already sync */ @@ -387,7 +387,7 @@ struct bad_iret_stack { struct pt_regs regs; }; -asmlinkage __visible +asmlinkage __visible notrace __kprobes struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s) { /*
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