Steven Rostedt (Red Hat) 70c8217acd tracing: Handle NULL formats in hold_module_trace_bprintk_format() ... If a task uses a non constant string for the format parameter in trace_printk(), then the trace_printk_fmt variable is set to NULL. This variable is then saved in the __trace_printk_fmt section. The function hold_module_trace_bprintk_format() checks to see if duplicate formats are used by modules, and reuses them if so (saves them to the list if it is new). But this function calls lookup_format() that does a strcmp() to the value (which is now NULL) and can cause a kernel oops. This wasn't an issue till 3debb0a9dd ("tracing: Fix trace_printk() to print when not using bprintk()") which added "__used" to the trace_printk_fmt variable, and before that, the kernel simply optimized it out (no NULL value was saved). The fix is simply to handle the NULL pointer in lookup_format() and have the caller ignore the value if it was NULL. Link: http://lkml.kernel.org/r/1464769870-18344-1-git-send-email-zhengjun.xing@intel.com Reported-by: xingzhen <zhengjun.xing@intel.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Fixes: 3debb0a9dd ("tracing: Fix trace_printk() to print when not using bprintk()") Cc: stable@vger.kernel.org # v3.5+ Signed-off-by: Steven Rostedt <rostedt@goodmis.org>		2016-06-20 09:46:12 -04:00
..
blktrace.c
bpf_trace.c	bpf, trace: use READ_ONCE for retrieving file ptr	2016-06-07 14:48:03 -07:00
ftrace.c	Three more changes.	2016-05-22 19:40:39 -07:00
Kconfig
Makefile
power-traces.c
ring_buffer_benchmark.c
ring_buffer.c
rpm-traces.c
trace_benchmark.c
trace_benchmark.h
trace_branch.c
trace_clock.c
trace_entries.h
trace_event_perf.c	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2016-05-17 16:26:30 -07:00
trace_events_filter_test.h
trace_events_filter.c
trace_events_hist.c
trace_events_trigger.c
trace_events.c	This includes two new updates for the ftrace infrastructure.	2016-05-18 18:55:19 -07:00
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	tracing: Handle NULL formats in hold_module_trace_bprintk_format()	2016-06-20 09:46:12 -04:00
trace_probe.c
trace_probe.h
trace_sched_switch.c
trace_sched_wakeup.c
trace_selftest_dynamic.c
trace_selftest.c
trace_seq.c
trace_stack.c
trace_stat.c
trace_stat.h
trace_syscalls.c
trace_uprobe.c
trace.c
trace.h
tracing_map.c
tracing_map.h