diff options
| author | Brian Behlendorf <[email protected]> | 2014-07-16 14:00:57 -0700 |
|---|---|---|
| committer | Brian Behlendorf <[email protected]> | 2014-07-22 09:47:24 -0700 |
| commit | 377e12f14a2c3694c3a733782b91ae7beecc44f3 (patch) | |
| tree | 0a727ab7595c6a819320325656bdb52319a6bbb9 | |
| parent | f6a869614e5bdf9a3819a845f7a90d8c9ede0fc3 (diff) | |
Rate limit debugging stack traces
There have been issues in the past where excessive debug logging
to the console has resulted in significant performance impacts.
In the vast majority of these cases only a few stack traces are
required to diagnose the issue. Therefore, stack traces dumped to
the console will now we limited to 5 every 60s.
Signed-off-by: Brian Behlendorf <[email protected]>
Signed-off-by: Prakash Surya <[email protected]>
Closes #374
| -rw-r--r-- | module/spl/spl-debug.c | 22 | ||||
| -rw-r--r-- | module/spl/spl-kmem.c | 2 |
2 files changed, 16 insertions, 8 deletions
diff --git a/module/spl/spl-debug.c b/module/spl/spl-debug.c index 93c3f31b8..6c4e043f0 100644 --- a/module/spl/spl-debug.c +++ b/module/spl/spl-debug.c @@ -37,6 +37,7 @@ #include <linux/proc_compat.h> #include <linux/file_compat.h> #include <linux/swap.h> +#include <linux/ratelimit.h> #include <sys/sysmacros.h> #include <sys/thread.h> #include <spl-debug.h> @@ -1073,15 +1074,22 @@ spl_debug_get_mb(void) } EXPORT_SYMBOL(spl_debug_get_mb); -void spl_debug_dumpstack(struct task_struct *tsk) -{ - extern void show_task(struct task_struct *); +/* + * Limit the number of stack traces dumped to not more than 5 every + * 60 seconds to prevent denial-of-service attacks from debug code. + */ +DEFINE_RATELIMIT_STATE(dumpstack_ratelimit_state, 60 * HZ, 5); - if (tsk == NULL) - tsk = current; +void +spl_debug_dumpstack(struct task_struct *tsk) +{ + if (__ratelimit(&dumpstack_ratelimit_state)) { + if (tsk == NULL) + tsk = current; - printk("SPL: Showing stack for process %d\n", tsk->pid); - dump_stack(); + printk("SPL: Showing stack for process %d\n", tsk->pid); + dump_stack(); + } } EXPORT_SYMBOL(spl_debug_dumpstack); diff --git a/module/spl/spl-kmem.c b/module/spl/spl-kmem.c index e458c2020..6389dc5aa 100644 --- a/module/spl/spl-kmem.c +++ b/module/spl/spl-kmem.c @@ -725,7 +725,7 @@ kmem_alloc_debug(size_t size, int flags, const char *func, int line, "large kmem_alloc(%llu, 0x%x) at %s:%d (%lld/%llu)\n", (unsigned long long) size, flags, func, line, kmem_alloc_used_read(), kmem_alloc_max); - dump_stack(); + spl_debug_dumpstack(NULL); } /* Use the correct allocator */ |