This is a note to let you know that I've just added the patch titled
tracing: Fix freeing of filter in create_filter() when set_str is false
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tracing-fix-freeing-of-filter-in-create_filter-when-set_str-is-false.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 8b0db1a5bdfcee0dbfa89607672598ae203c9045 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>
Date: Wed, 23 Aug 2017 12:46:27 -0400
Subject: tracing: Fix freeing of filter in create_filter() when set_str is false
From: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
commit 8b0db1a5bdfcee0dbfa89607672598ae203c9045 upstream.
Performing the following task with kmemleak enabled:
# cd /sys/kernel/tracing/events/irq/irq_handler_entry/
# echo 'enable_event:kmem:kmalloc:3 if irq >' > trigger
# echo 'enable_event:kmem:kmalloc:3 if irq > 31' > trigger
# echo scan > /sys/kernel/debug/kmemleak
# cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff8800b9290308 (size 32):
comm "bash", pid 1114, jiffies 4294848451 (age 141.139s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff81cef5aa>] kmemleak_alloc+0x4a/0xa0
[<ffffffff81357938>] kmem_cache_alloc_trace+0x158/0x290
[<ffffffff81261c09>] create_filter_start.constprop.28+0x99/0x940
[<ffffffff812639c9>] create_filter+0xa9/0x160
[<ffffffff81263bdc>] create_event_filter+0xc/0x10
[<ffffffff812655e5>] set_trigger_filter+0xe5/0x210
[<ffffffff812660c4>] event_enable_trigger_func+0x324/0x490
[<ffffffff812652e2>] event_trigger_write+0x1a2/0x260
[<ffffffff8138cf87>] __vfs_write+0xd7/0x380
[<ffffffff8138f421>] vfs_write+0x101/0x260
[<ffffffff8139187b>] SyS_write+0xab/0x130
[<ffffffff81cfd501>] entry_SYSCALL_64_fastpath+0x1f/0xbe
[<ffffffffffffffff>] 0xffffffffffffffff
The function create_filter() is passed a 'filterp' pointer that gets
allocated, and if "set_str" is true, it is up to the caller to free it, even
on error. The problem is that the pointer is not freed by create_filter()
when set_str is false. This is a bug, and it is not up to the caller to free
the filter on error if it doesn't care about the string.
Link: http://lkml.kernel.org/r/1502705898-27571-2-git-send-email-chuhu@xxxxxxxxxx
Fixes: 38b78eb85 ("tracing: Factorize filter creation")
Reported-by: Chunyu Hu <chuhu@xxxxxxxxxx>
Tested-by: Chunyu Hu <chuhu@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/trace/trace_events_filter.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -1926,6 +1926,10 @@ static int create_filter(struct trace_ev
if (err && set_str)
append_filter_err(ps, filter);
}
+ if (err && !set_str) {
+ free_event_filter(filter);
+ filter = NULL;
+ }
create_filter_finish(ps);
*filterp = filter;
Patches currently in stable-queue which might be from rostedt@xxxxxxxxxxx are
queue-4.9/ftrace-check-for-null-ret_stack-on-profile-function-graph-entry-function.patch
queue-4.9/tracing-fix-freeing-of-filter-in-create_filter-when-set_str-is-false.patch
queue-4.9/tracing-call-clear_boot_tracer-at-lateinit_sync.patch
queue-4.9/tracing-fix-kmemleak-in-tracing_map_array_free.patch