From abd4f7505bafdd6c5319fe3cb5caf9af6104e17a Mon Sep 17 00:00:00 2001 From: Masoud Asgharifard Sharbiani Date: Sun, 22 Jul 2007 11:12:28 +0200 Subject: 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 Signed-off-by: Andi Kleen [ 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 --- kernel/sysctl.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'kernel/sysctl.c') diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 222299844ad1..ddebf3f2affe 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1203,6 +1203,16 @@ static ctl_table fs_table[] = { }; static ctl_table debug_table[] = { +#ifdef CONFIG_X86 + { + .ctl_name = CTL_UNNUMBERED, + .procname = "exception-trace", + .data = &show_unhandled_signals, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec + }, +#endif { .ctl_name = 0 } }; -- cgit v1.2.3