linux/kernel/trace
Steven Rostedt (Red Hat) 39b5552cd5 ftrace: Use current addr when converting to nop in __ftrace_replace_code()
In __ftrace_replace_code(), when converting the call to a nop in a function
it needs to compare against the "curr" (current) value of the ftrace ops, and
not the "new" one. It currently does not affect x86 which is the only arch
to do the trampolines with function graph tracer, but when other archs that do
depend on this code implement the function graph trampoline, it can crash.

Here's an example when ARM uses the trampolines (in the future):

 ------------[ cut here ]------------
 WARNING: CPU: 0 PID: 9 at kernel/trace/ftrace.c:1716 ftrace_bug+0x17c/0x1f4()
 Modules linked in: omap_rng rng_core ipv6
 CPU: 0 PID: 9 Comm: migration/0 Not tainted 3.16.0-test-10959-gf0094b28f303-dirty #52
 [<c02188f4>] (unwind_backtrace) from [<c021343c>] (show_stack+0x20/0x24)
 [<c021343c>] (show_stack) from [<c095a674>] (dump_stack+0x78/0x94)
 [<c095a674>] (dump_stack) from [<c02532a0>] (warn_slowpath_common+0x7c/0x9c)
 [<c02532a0>] (warn_slowpath_common) from [<c02532ec>] (warn_slowpath_null+0x2c/0x34)
 [<c02532ec>] (warn_slowpath_null) from [<c02cbac4>] (ftrace_bug+0x17c/0x1f4)
 [<c02cbac4>] (ftrace_bug) from [<c02cc44c>] (ftrace_replace_code+0x80/0x9c)
 [<c02cc44c>] (ftrace_replace_code) from [<c02cc658>] (ftrace_modify_all_code+0xb8/0x164)
 [<c02cc658>] (ftrace_modify_all_code) from [<c02cc718>] (__ftrace_modify_code+0x14/0x1c)
 [<c02cc718>] (__ftrace_modify_code) from [<c02c7244>] (multi_cpu_stop+0xf4/0x134)
 [<c02c7244>] (multi_cpu_stop) from [<c02c6e90>] (cpu_stopper_thread+0x54/0x130)
 [<c02c6e90>] (cpu_stopper_thread) from [<c0271cd4>] (smpboot_thread_fn+0x1ac/0x1bc)
 [<c0271cd4>] (smpboot_thread_fn) from [<c026ddf0>] (kthread+0xe0/0xfc)
 [<c026ddf0>] (kthread) from [<c020f318>] (ret_from_fork+0x14/0x20)
 ---[ end trace dc9ce72c5b617d8f ]---
[   65.047264] ftrace failed to modify [<c0208580>] asm_do_IRQ+0x10/0x1c
[   65.054070]  actual: 85:1b:00:eb

Fixes: 7413af1fb7 "ftrace: Make get_ftrace_addr() and get_ftrace_addr_old() global"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-08-22 21:04:35 -04:00
..
Kconfig tracing: Remove function_trace_stop and HAVE_FUNCTION_TRACE_MCOUNT_TEST 2014-07-18 13:58:12 -04:00
Makefile tracing: Move the trace_seq_* functions into its own trace_seq.c file 2014-07-01 07:13:35 -04:00
blktrace.c Most of the changes were largely clean ups, and some documentation. 2014-04-03 10:26:31 -07:00
ftrace.c ftrace: Use current addr when converting to nop in __ftrace_replace_code() 2014-08-22 21:04:35 -04:00
power-traces.c PM / tracing: remove deprecated power trace API 2013-01-26 00:39:12 +01:00
ring_buffer.c This contains a fix for two long standing bugs. Both of which are 2014-08-09 17:29:36 -07:00
ring_buffer_benchmark.c trace: Replace hardcoding of 19 with MAX_NICE 2014-02-27 12:41:03 +01:00
rpm-traces.c PM / Runtime: Introduce trace points for tracing rpm_* functions 2011-09-27 22:53:27 +02:00
trace.c Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-08-05 17:46:42 -07:00
trace.h tracing: let user specify tracing_thresh after selecting function_graph 2014-07-18 15:48:52 -04:00
trace_benchmark.c tracing: Only calculate stats of tracepoint benchmarks for 2^32 times 2014-06-06 00:41:38 -04:00
trace_benchmark.h tracing: Add tracepoint benchmark tracepoint 2014-05-29 22:49:54 -04:00
trace_branch.c tracing: Update event filters for multibuffer 2013-11-05 16:50:20 -05:00
trace_clock.c tracing: Fix wraparound problems in "uptime" trace clock 2014-07-21 09:56:12 -04:00
trace_entries.h tracing: Add trace_puts() for even faster trace_printk() tracing 2013-03-15 00:35:55 -04:00
trace_event_perf.c perf: Check permission only for parent tracepoint event 2014-07-28 10:01:38 +02:00
trace_events.c Oleg Nesterov did several clean ups with the tracing filter code. 2014-08-04 12:02:48 -07:00
trace_events_filter.c tracing: Kill "filter_string" arg of replace_preds() 2014-07-16 14:58:53 -04:00
trace_events_filter_test.h tracing/filter: Add startup tests for events filter 2011-08-19 14:35:59 -04:00
trace_events_trigger.c tracing: Use rcu_dereference_sched() for trace event triggers 2014-05-02 23:12:42 -04:00
trace_export.c tracing: Fix anonymous unions in struct ftrace_event_call 2014-04-09 20:02:55 -04:00
trace_functions.c tracing: Remove mock up poll wait function 2014-04-30 08:40:05 -04:00
trace_functions_graph.c tracing: Convert local function_graph functions to static 2014-07-18 21:16:06 -04:00
trace_irqsoff.c tracing: Allow irq/preempt tracers to be used by instances 2014-04-21 13:59:29 -04:00
trace_kdb.c tracing: Consolidate max_tr into main trace_array structure 2013-03-15 00:35:40 -04:00
trace_kprobe.c Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-06-12 19:18:49 -07:00
trace_mmiotrace.c tracing: Update event filters for multibuffer 2013-11-05 16:50:20 -05:00
trace_nop.c tracing: Remove mock up poll wait function 2014-04-30 08:40:05 -04:00
trace_output.c tracing: Add trace_seq_buffer_ptr() helper function 2014-07-01 07:13:39 -04:00
trace_output.h tracing: Make trace_seq_putmem_hex() more robust 2014-07-01 07:13:37 -04:00
trace_printk.c tracing: Add __tracepoint_string() to export string pointers 2013-07-26 13:39:44 -04:00
trace_probe.c kprobes, ftrace: Use NOKPROBE_SYMBOL macro in ftrace 2014-04-24 10:26:39 +02:00
trace_probe.h kprobes, ftrace: Use NOKPROBE_SYMBOL macro in ftrace 2014-04-24 10:26:39 +02:00
trace_sched_switch.c tracing: Update event filters for multibuffer 2013-11-05 16:50:20 -05:00
trace_sched_wakeup.c tracing: Remove mock up poll wait function 2014-04-30 08:40:05 -04:00
trace_selftest.c tracing: Add static to local functions 2014-04-21 14:00:46 -04:00
trace_selftest_dynamic.c ftrace: Add self-tests for multiple function trace users 2011-05-18 19:24:51 -04:00
trace_seq.c tracing: Remove trace_seq_reserve() 2014-07-01 07:13:37 -04:00
trace_stack.c tracing: Print max callstack on stacktrace bug 2014-06-02 16:43:49 -04:00
trace_stat.c trace/trace_stat: use rbtree postorder iteration helper instead of opencoding 2013-11-05 16:01:47 -05:00
trace_stat.h tracing/stat: Add stat_release() callback 2009-07-10 12:14:05 +02:00
trace_syscalls.c tracing: Consolidate event trigger code 2014-01-09 21:20:07 -05:00
trace_uprobe.c tracing/uprobes: Kill the dead TRACE_EVENT_FL_USE_CALL_FILTER logic 2014-07-16 14:25:19 -04:00