ddf6e0e507
If the set_ftrace_filter is cleared by writing just whitespace to it, then the filter hash refcounts will be decremented but not updated. This causes two bugs: 1) No functions will be enabled for tracing when they all should be 2) If the users clears the set_ftrace_filter twice, it will crash ftrace: ------------[ cut here ]------------ WARNING: at /home/rostedt/work/git/linux-trace.git/kernel/trace/ftrace.c:1384 __ftrace_hash_rec_update.part.27+0x157/0x1a7() Modules linked in: Pid: 2330, comm: bash Not tainted 3.1.0-test+ #32 Call Trace: [<ffffffff81051828>] warn_slowpath_common+0x83/0x9b [<ffffffff8105185a>] warn_slowpath_null+0x1a/0x1c [<ffffffff810ba362>] __ftrace_hash_rec_update.part.27+0x157/0x1a7 [<ffffffff810ba6e8>] ? ftrace_regex_release+0xa7/0x10f [<ffffffff8111bdfe>] ? kfree+0xe5/0x115 [<ffffffff810ba51e>] ftrace_hash_move+0x2e/0x151 [<ffffffff810ba6fb>] ftrace_regex_release+0xba/0x10f [<ffffffff8112e49a>] fput+0xfd/0x1c2 [<ffffffff8112b54c>] filp_close+0x6d/0x78 [<ffffffff8113a92d>] sys_dup3+0x197/0x1c1 [<ffffffff8113a9a6>] sys_dup2+0x4f/0x54 [<ffffffff8150cac2>] system_call_fastpath+0x16/0x1b ---[ end trace 77a3a7ee73794a02 ]--- Link: http://lkml.kernel.org/r/20111101141420.GA4918@debian Reported-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> |
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| .. | ||
| blktrace.c | ||
| ftrace.c | ||
| Kconfig | ||
| Makefile | ||
| power-traces.c | ||
| ring_buffer_benchmark.c | ||
| ring_buffer.c | ||
| rpm-traces.c | ||
| trace_branch.c | ||
| trace_clock.c | ||
| trace_entries.h | ||
| trace_event_perf.c | ||
| trace_events_filter_test.h | ||
| trace_events_filter.c | ||
| trace_events.c | ||
| trace_export.c | ||
| trace_functions_graph.c | ||
| trace_functions.c | ||
| trace_irqsoff.c | ||
| trace_kdb.c | ||
| trace_kprobe.c | ||
| trace_mmiotrace.c | ||
| trace_nop.c | ||
| trace_output.c | ||
| trace_output.h | ||
| trace_printk.c | ||
| trace_sched_switch.c | ||
| trace_sched_wakeup.c | ||
| trace_selftest_dynamic.c | ||
| trace_selftest.c | ||
| trace_stack.c | ||
| trace_stat.c | ||
| trace_stat.h | ||
| trace_syscalls.c | ||
| trace_workqueue.c | ||
| trace.c | ||
| trace.h | ||