Commit 748f2edb52712aa3d926470a888608dc500d17e8
Committed by
Linus Torvalds
Linus Torvalds
1 parent
f2f30ebca6
Exists in
master
and in
4 other branches
[PATCH] x86 NMI: better support for debuggers
This patch adds a notify to the die_nmi notify that the system is about to be taken down. If the notify is handled with a NOTIFY_STOP return, the system is given a new lease on life. We also change the nmi watchdog to carry on if die_nmi returns. This give debug code a chance to a) catch watchdog timeouts and b) possibly allow the system to continue, realizing that the time out may be due to debugger activities such as single stepping which is usually done with "other" cpus held. Signed-off-by: George Anzinger<george@mvista.com> Cc: Keith Owens <kaos@ocs.com.au> Signed-off-by: George Anzinger <george@mvista.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Showing 3 changed files with 17 additions and 3 deletions Side-by-side Diff
arch/i386/kernel/nmi.c
| ... | ... | @@ -501,8 +501,11 @@ |
| 501 | 501 | */ |
| 502 | 502 | alert_counter[cpu]++; |
| 503 | 503 | if (alert_counter[cpu] == 5*nmi_hz) |
| 504 | + /* | |
| 505 | + * die_nmi will return ONLY if NOTIFY_STOP happens.. | |
| 506 | + */ | |
| 504 | 507 | die_nmi(regs, "NMI Watchdog detected LOCKUP"); |
| 505 | - } else { | |
| 508 | + | |
| 506 | 509 | last_irq_sums[cpu] = sum; |
| 507 | 510 | alert_counter[cpu] = 0; |
| 508 | 511 | } |
arch/i386/kernel/traps.c
| ... | ... | @@ -565,6 +565,10 @@ |
| 565 | 565 | |
| 566 | 566 | void die_nmi (struct pt_regs *regs, const char *msg) |
| 567 | 567 | { |
| 568 | + if (notify_die(DIE_NMIWATCHDOG, msg, regs, 0, 0, SIGINT) == | |
| 569 | + NOTIFY_STOP) | |
| 570 | + return; | |
| 571 | + | |
| 568 | 572 | spin_lock(&nmi_print_lock); |
| 569 | 573 | /* |
| 570 | 574 | * We are in trouble anyway, lets at least try |
include/asm-i386/kdebug.h
| ... | ... | @@ -41,9 +41,16 @@ |
| 41 | 41 | DIE_PAGE_FAULT, |
| 42 | 42 | }; |
| 43 | 43 | |
| 44 | -static inline int notify_die(enum die_val val,char *str,struct pt_regs *regs,long err,int trap, int sig) | |
| 44 | +static inline int notify_die(enum die_val val, const char *str, | |
| 45 | + struct pt_regs *regs, long err, int trap, int sig) | |
| 45 | 46 | { |
| 46 | - struct die_args args = { .regs=regs, .str=str, .err=err, .trapnr=trap,.signr=sig }; | |
| 47 | + struct die_args args = { | |
| 48 | + .regs = regs, | |
| 49 | + .str = str, | |
| 50 | + .err = err, | |
| 51 | + .trapnr = trap, | |
| 52 | + .signr = sig | |
| 53 | + }; | |
| 47 | 54 | return notifier_call_chain(&i386die_chain, val, &args); |
| 48 | 55 | } |
| 49 | 56 |