This is a note to let you know that I've just added the patch titled
tracing: Fix memory leaks in trace_events_hist.c
to the 5.6-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-memory-leaks-in-trace_events_hist.c.patch
and it can be found in the queue-5.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit af87396bfdaf91a5077690f496537b9bc3f53828
Author: Vamshi K Sthambamkadi <vamshi.k.sthambamkadi@xxxxxxxxx>
Date: Wed Apr 22 11:45:06 2020 +0530
tracing: Fix memory leaks in trace_events_hist.c
[ Upstream commit 9da73974eb9c965dd9989befb593b8c8da9e4bdc ]
kmemleak report 1:
[<9092c50b>] kmem_cache_alloc_trace+0x138/0x270
[<05a2c9ed>] create_field_var+0xcf/0x180
[<528a2d68>] action_create+0xe2/0xc80
[<63f50b61>] event_hist_trigger_func+0x15b5/0x1920
[<28ea5d3d>] trigger_process_regex+0x7b/0xc0
[<3138e86f>] event_trigger_write+0x4d/0xb0
[<ffd66c19>] __vfs_write+0x30/0x200
[<4f424a0d>] vfs_write+0x96/0x1b0
[<da59a290>] ksys_write+0x53/0xc0
[<3717101a>] __ia32_sys_write+0x15/0x20
[<c5f23497>] do_fast_syscall_32+0x70/0x250
[<46e2629c>] entry_SYSENTER_32+0xaf/0x102
This is because save_vars[] of struct hist_trigger_data are
not destroyed
kmemleak report 2:
[<9092c50b>] kmem_cache_alloc_trace+0x138/0x270
[<6e5e97c5>] create_var+0x3c/0x110
[<de82f1b9>] create_field_var+0xaf/0x180
[<528a2d68>] action_create+0xe2/0xc80
[<63f50b61>] event_hist_trigger_func+0x15b5/0x1920
[<28ea5d3d>] trigger_process_regex+0x7b/0xc0
[<3138e86f>] event_trigger_write+0x4d/0xb0
[<ffd66c19>] __vfs_write+0x30/0x200
[<4f424a0d>] vfs_write+0x96/0x1b0
[<da59a290>] ksys_write+0x53/0xc0
[<3717101a>] __ia32_sys_write+0x15/0x20
[<c5f23497>] do_fast_syscall_32+0x70/0x250
[<46e2629c>] entry_SYSENTER_32+0xaf/0x102
struct hist_field allocated through create_var() do not initialize
"ref" field to 1. The code in __destroy_hist_field() does not destroy
object if "ref" is initialized to zero, the condition
if (--hist_field->ref > 1) always passes since unsigned int wraps.
kmemleak report 3:
[<f8666fcc>] __kmalloc_track_caller+0x139/0x2b0
[<bb7f80a5>] kstrdup+0x27/0x50
[<39d70006>] init_var_ref+0x58/0xd0
[<8ca76370>] create_var_ref+0x89/0xe0
[<f045fc39>] action_create+0x38f/0xc80
[<7c146821>] event_hist_trigger_func+0x15b5/0x1920
[<07de3f61>] trigger_process_regex+0x7b/0xc0
[<e87daf8f>] event_trigger_write+0x4d/0xb0
[<19bf1512>] __vfs_write+0x30/0x200
[<64ce4d27>] vfs_write+0x96/0x1b0
[<a6f34170>] ksys_write+0x53/0xc0
[<7d4230cd>] __ia32_sys_write+0x15/0x20
[<8eadca00>] do_fast_syscall_32+0x70/0x250
[<235cf985>] entry_SYSENTER_32+0xaf/0x102
hist_fields (system & event_name) are not freed
Link: http://lkml.kernel.org/r/20200422061503.GA5151@cosmos
Signed-off-by: Vamshi K Sthambamkadi <vamshi.k.sthambamkadi@xxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 5f6834a2bf411..fcab11cc6833b 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -3320,6 +3320,9 @@ static void __destroy_hist_field(struct hist_field *hist_field)
kfree(hist_field->name);
kfree(hist_field->type);
+ kfree(hist_field->system);
+ kfree(hist_field->event_name);
+
kfree(hist_field);
}
@@ -4382,6 +4385,7 @@ static struct hist_field *create_var(struct hist_trigger_data *hist_data,
goto out;
}
+ var->ref = 1;
var->flags = HIST_FIELD_FL_VAR;
var->var.idx = idx;
var->var.hist_data = var->hist_data = hist_data;
@@ -5011,6 +5015,9 @@ static void destroy_field_vars(struct hist_trigger_data *hist_data)
for (i = 0; i < hist_data->n_field_vars; i++)
destroy_field_var(hist_data->field_vars[i]);
+
+ for (i = 0; i < hist_data->n_save_vars; i++)
+ destroy_field_var(hist_data->save_vars[i]);
}
static void save_field_var(struct hist_trigger_data *hist_data,
