diff options
| author | Masoud Asgharifard Sharbiani <masouds@google.com> | 2007-07-22 11:12:28 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-22 11:03:37 -0700 |
| commit | abd4f7505bafdd6c5319fe3cb5caf9af6104e17a (patch) | |
| tree | a543fce720331dbf6194a2c0471f36b7727b9736 /arch/i386 | |
| parent | 5fa63fccc579ac609fc7f86d29ccb3a2edf910d7 (diff) | |
x86: i386-show-unhandled-signals-v3
This patch makes the i386 behave the same way that x86_64 does when a
segfault happens. A line gets printed to the kernel log so that tools
that need to check for failures can behave more uniformly between
debug.show_unhandled_signals sysctl variable to 0 (or by doing echo 0 >
/proc/sys/debug/exception-trace)
Also, all of the lines being printed are now using printk_ratelimit() to
deny the ability of DoS from a local user with a program like the
following:
main()
{
while (1)
if (!fork()) *(int *)0 = 0;
}
This new revision also includes the fix that Andrew did which got rid of
new sysctl that was added to the system in earlier versions of this.
Also, 'show-unhandled-signals' sysctl has been renamed back to the old
'exception-trace' to avoid breakage of people's scripts.
AK: Enabling by default for i386 will be likely controversal, but let's see what happens
AK: Really folks, before complaining just fix your segfaults
AK: I bet this will find a lot of silent issues
Signed-off-by: Masoud Sharbiani <masouds@google.com>
Signed-off-by: Andi Kleen <ak@suse.de>
[ Personally, I've found the complaints useful on x86-64, so I'm all for
this. That said, I wonder if we could do it more prettily.. -Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/i386')
| -rw-r--r-- | arch/i386/kernel/signal.c | 7 | ||||
| -rw-r--r-- | arch/i386/kernel/traps.c | 7 | ||||
| -rw-r--r-- | arch/i386/mm/fault.c | 10 |
3 files changed, 24 insertions, 0 deletions
diff --git a/arch/i386/kernel/signal.c b/arch/i386/kernel/signal.c index d574e38f0f7..f5dd85656c1 100644 --- a/arch/i386/kernel/signal.c +++ b/arch/i386/kernel/signal.c @@ -199,6 +199,13 @@ asmlinkage int sys_sigreturn(unsigned long __unused) return eax; badframe: + if (show_unhandled_signals && printk_ratelimit()) + printk("%s%s[%d] bad frame in sigreturn frame:%p eip:%lx" + " esp:%lx oeax:%lx\n", + current->pid > 1 ? KERN_INFO : KERN_EMERG, + current->comm, current->pid, frame, regs->eip, + regs->esp, regs->orig_eax); + force_sig(SIGSEGV, current); return 0; } diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c index 57772a18c39..438949da3b6 100644 --- a/arch/i386/kernel/traps.c +++ b/arch/i386/kernel/traps.c @@ -618,6 +618,13 @@ fastcall void __kprobes do_general_protection(struct pt_regs * regs, current->thread.error_code = error_code; current->thread.trap_no = 13; + if (show_unhandled_signals && unhandled_signal(current, SIGSEGV) && + printk_ratelimit()) + printk(KERN_INFO + "%s[%d] general protection eip:%lx esp:%lx error:%lx\n", + current->comm, current->pid, + regs->eip, regs->esp, error_code); + force_sig(SIGSEGV, current); return; diff --git a/arch/i386/mm/fault.c b/arch/i386/mm/fault.c index e92a1012493..01ffdd4964f 100644 --- a/arch/i386/mm/fault.c +++ b/arch/i386/mm/fault.c @@ -283,6 +283,8 @@ static inline int vmalloc_fault(unsigned long address) return 0; } +int show_unhandled_signals = 1; + /* * This routine handles page faults. It determines the address, * and the problem, and then passes it off to one of the appropriate @@ -469,6 +471,14 @@ bad_area_nosemaphore: if (is_prefetch(regs, address, error_code)) return; + if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) && + printk_ratelimit()) { + printk("%s%s[%d]: segfault at %08lx eip %08lx " + "esp %08lx error %lx\n", + tsk->pid > 1 ? KERN_INFO : KERN_EMERG, + tsk->comm, tsk->pid, address, regs->eip, + regs->esp, error_code); + } tsk->thread.cr2 = address; /* Kernel addresses are always protection faults */ tsk->thread.error_code = error_code | (address >= TASK_SIZE); |