From: Keita Suzuki keitasuzuki.park@sslab.ics.keio.ac.jp

When failing in the allocation of filter_item, process_system_preds() goes to fail_mem, where the allocated filter is freed.

However, this leads to memory leak of filter->filter_string and filter->prog, which is allocated before and in process_preds(). This bug has been detected by kmemleak as well.

Fix this by changing kfree to __free_fiter.

unreferenced object 0xffff8880658007c0 (size 32): comm "bash", pid 579, jiffies 4295096372 (age 17.752s) hex dump (first 32 bytes): 63 6f 6d 6d 6f 6e 5f 70 69 64 20 20 3e 20 31 30 common_pid > 10 00 00 00 00 00 00 00 00 65 73 00 00 00 00 00 00 ........es...... backtrace: [<0000000067441602>] kstrdup+0x2d/0x60 [<00000000141cf7b7>] apply_subsystem_event_filter+0x378/0x932 [<000000009ca32334>] subsystem_filter_write+0x5a/0x90 [<0000000072da2bee>] vfs_write+0xe1/0x240 [<000000004f14f473>] ksys_write+0xb4/0x150 [<00000000a968b4a0>] do_syscall_64+0x6d/0x1e0 [<000000001a189f40>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 unreferenced object 0xffff888060c22d00 (size 64): comm "bash", pid 579, jiffies 4295096372 (age 17.752s) hex dump (first 32 bytes): 01 00 00 00 00 00 00 00 00 e8 d7 41 80 88 ff ff ...........A.... 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000b8c1b109>] process_preds+0x243/0x1820 [<000000003972c7f0>] apply_subsystem_event_filter+0x3be/0x932 [<000000009ca32334>] subsystem_filter_write+0x5a/0x90 [<0000000072da2bee>] vfs_write+0xe1/0x240 [<000000004f14f473>] ksys_write+0xb4/0x150 [<00000000a968b4a0>] do_syscall_64+0x6d/0x1e0 [<000000001a189f40>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 unreferenced object 0xffff888041d7e800 (size 512): comm "bash", pid 579, jiffies 4295096372 (age 17.752s) hex dump (first 32 bytes): 70 bc 85 97 ff ff ff ff 0a 00 00 00 00 00 00 00 p............... 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<000000001e04af34>] process_preds+0x71a/0x1820 [<000000003972c7f0>] apply_subsystem_event_filter+0x3be/0x932 [<000000009ca32334>] subsystem_filter_write+0x5a/0x90 [<0000000072da2bee>] vfs_write+0xe1/0x240 [<000000004f14f473>] ksys_write+0xb4/0x150 [<00000000a968b4a0>] do_syscall_64+0x6d/0x1e0 [<000000001a189f40>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Link: http://lkml.kernel.org/r/20191211091258.11310-1-keitasuzuki.park@sslab.ics.k...

Cc: Ingo Molnar mingo@redhat.com Cc: stable@vger.kernel.org Fixes: 404a3add43c9c ("tracing: Only add filter list when needed") Signed-off-by: Keita Suzuki keitasuzuki.park@sslab.ics.keio.ac.jp Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org --- kernel/trace/trace_events_filter.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index c9a74f82b14a..bf44f6bbd0c3 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -1662,7 +1662,7 @@ static int process_system_preds(struct trace_subsystem_dir *dir, parse_error(pe, FILT_ERR_BAD_SUBSYS_FILTER, 0); return -EINVAL; fail_mem: - kfree(filter); + __free_filter(filter); /* If any call succeeded, we still need to sync */ if (!fail) tracepoint_synchronize_unregister();