linux/kernel/trace
Steven Rostedt ddf6e0e507 ftrace: Fix hash record accounting bug
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>
2011-12-05 13:28:47 -05:00
..
blktrace.c kernel: Fix files explicitly needing EXPORT_SYMBOL infrastructure 2011-10-31 19:30:05 -04:00
ftrace.c ftrace: Fix hash record accounting bug 2011-12-05 13:28:47 -05:00
Kconfig trace events: Update version number reference to new 3.x scheme for EVENT_POWER_TRACING_DEPRECATED 2011-07-25 09:37:21 +02:00
Makefile Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2011-10-26 17:03:38 +02:00
power-traces.c
ring_buffer_benchmark.c tracing: Use NUMA allocation for per-cpu ring buffer pages 2011-06-14 22:04:39 -04:00
ring_buffer.c Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2011-10-26 17:03:38 +02:00
rpm-traces.c PM / Runtime: Introduce trace points for tracing rpm_* functions 2011-09-27 22:53:27 +02:00
trace_branch.c
trace_clock.c tracing: Add a counter clock for those that do not trust clocks 2011-09-19 11:35:58 -04:00
trace_entries.h tracing: Have dynamic size event stack traces 2011-07-14 16:36:53 -04:00
trace_event_perf.c
trace_events_filter_test.h tracing/filter: Add startup tests for events filter 2011-08-19 14:35:59 -04:00
trace_events_filter.c tracing: Restore system filter behavior 2011-12-05 13:28:45 -05:00
trace_events.c tracing: fix event_subsystem ref counting 2011-12-05 13:28:44 -05:00
trace_export.c tracing: Replace trace_event struct array with pointer array 2011-02-02 21:37:13 -05:00
trace_functions_graph.c tracing: Still trace filtered irq functions when irq trace is disabled 2011-07-07 22:26:27 -04:00
trace_functions.c ftrace: Fix regression of :mod:module function enabling 2011-07-07 11:30:08 -04:00
trace_irqsoff.c Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2011-10-26 17:03:38 +02:00
trace_kdb.c
trace_kprobe.c ftrace/kprobes: Fix not to delete probes if in use 2011-10-10 15:13:03 -04:00
trace_mmiotrace.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
trace_nop.c
trace_output.c tracing: Have dynamic size event stack traces 2011-07-14 16:36:53 -04:00
trace_output.h
trace_printk.c tracing: Clean up tb_fmt to not give faulty compile warning 2011-08-10 20:36:32 -04:00
trace_sched_switch.c tracing: Remove obsolete sched_switch tracer 2011-02-08 17:14:56 -05:00
trace_sched_wakeup.c tracing, function_graph: Remove dependency of abstime and duration fields on latency 2011-06-14 22:48:47 -04:00
trace_selftest_dynamic.c ftrace: Add self-tests for multiple function trace users 2011-05-18 19:24:51 -04:00
trace_selftest.c ftrace: Add self-tests for multiple function trace users 2011-05-18 19:24:51 -04:00
trace_stack.c tracing: Convert to kstrtoul_from_user 2011-06-14 22:48:50 -04:00
trace_stat.c
trace_stat.h
trace_syscalls.c kernel: Add <linux/module.h> to files using it implicitly 2011-10-31 09:20:12 -04:00
trace_workqueue.c
trace.c Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2011-10-26 17:03:38 +02:00
trace.h tracing: Warn on output if the function tracer was found corrupted 2011-10-11 09:13:25 -04:00