Messages in this thread Patch in this message | | | Date | Fri, 9 Jun 2006 10:59:20 +0200 | From | Ingo Molnar <> | Subject | [patch, -rc6-mm1] irqflags tracing: fix x86_64 entry/exit |
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* Paolo Ornati <ornati@fastwebnet.it> wrote:
> Wow, now I can reproduce it easly :) > > Just run under "gdb" a program that segfaults: > > void main(void) > { > *(int*)(0) = 1; > } > > and it will trigger.
thanks - please try the fix below - it has solved the problem on my testbox.
Ingo
------------- Subject: irqflags tracing: fix x86_64 entry/exit From: Ingo Molnar <mingo@elte.hu>
the x86_64 portion of the irqflags code did not properly trace the "paranoid userspace" type of syscall/ptrace exit variant.
A testcase Paolo Ornati has discovered triggers a lock validator assert due to this bug.
Signed-off-by: Ingo Molnar <mingo@elte.hu> --- arch/x86_64/kernel/entry.S | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
Index: linux/arch/x86_64/kernel/entry.S =================================================================== --- linux.orig/arch/x86_64/kernel/entry.S +++ linux/arch/x86_64/kernel/entry.S @@ -50,9 +50,10 @@ #define retint_kernel retint_restore_args #endif -.macro TRACE_IRQS_IRETQ + +.macro TRACE_IRQS_IRETQ offset=ARGOFFSET #ifdef CONFIG_TRACE_IRQFLAGS - bt $9,EFLAGS-ARGOFFSET(%rsp) /* interrupts off? */ + bt $9,EFLAGS-\offset(%rsp) /* interrupts off? */ jnc 1f TRACE_IRQS_ON 1: @@ -809,9 +810,9 @@ error_exit: andl %edi,%edx jnz retint_careful /* - * The iret will restore flags: + * The iret might restore flags: */ - TRACE_IRQS_ON + TRACE_IRQS_IRETQ swapgs RESTORE_ARGS 0,8,0 jmp iret_label @@ -999,6 +1000,7 @@ paranoid_exit: testl $3,CS(%rsp) jnz paranoid_userspace paranoid_swapgs: + TRACE_IRQS_IRETQ 0 swapgs paranoid_restore: RESTORE_ALL 8 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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