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| author |   Jiri Slaby <jslaby@suse.cz> | 2013-10-25 15:06:58 +0200 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2013-11-12 21:06:06 +0100 |
| commit | 5f01c98859073cb512b01d4fad74b5f4e047be0b (patch) | |
| tree | 57dae13988d5979e69e310049160ed9af1ea14a3 /arch/x86/platform/uv/uv_nmi.c | |
| parent | Merge branch 'x86-uv-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (diff) | |
| download | linux-dev-5f01c98859073cb512b01d4fad74b5f4e047be0b.tar.xz linux-dev-5f01c98859073cb512b01d4fad74b5f4e047be0b.zip | |
x86/dumpstack: Fix printk_address for direct addresses
Consider a kernel crash in a module, simulated the following way:
static int my_init(void)
{
char *map = (void *)0x5;
*map = 3;
return 0;
}
module_init(my_init);
When we turn off FRAME_POINTERs, the very first instruction in
that function causes a BUG. The problem is that we print IP in
the BUG report using %pB (from printk_address). And %pB
decrements the pointer by one to fix printing addresses of
functions with tail calls.
This was added in commit 71f9e59800e5ad4 ("x86, dumpstack: Use
%pB format specifier for stack trace") to fix the call stack
printouts.
So instead of correct output:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000005
IP: [<ffffffffa01ac000>] my_init+0x0/0x10 [pb173]
We get:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000005
IP: [<ffffffffa0152000>] 0xffffffffa0151fff
To fix that, we use %pS only for stack addresses printouts (via
newly added printk_stack_address) and %pB for regs->ip (via
printk_address). I.e. we revert to the old behaviour for all
except call stacks. And since from all those reliable is 1, we
remove that parameter from printk_address.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: joe@perches.com
Cc: jirislaby@gmail.com
Link: http://lkml.kernel.org/r/1382706418-8435-1-git-send-email-jslaby@suse.cz
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/platform/uv/uv_nmi.c')
| -rw-r--r-- | arch/x86/platform/uv/uv_nmi.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/platform/uv/uv_nmi.c b/arch/x86/platform/uv/uv_nmi.c index 2e863ad4a772..8eeccba73130 100644 --- a/arch/x86/platform/uv/uv_nmi.c +++ b/arch/x86/platform/uv/uv_nmi.c @@ -399,7 +399,7 @@ static void uv_nmi_dump_cpu_ip(int cpu, struct pt_regs *regs) printk(KERN_DEFAULT "UV: %4d %6d %-32.32s ", cpu, current->pid, current->comm); - printk_address(regs->ip, 1); + printk_address(regs->ip); } /* Dump this cpu's state */ |