From: Donggeun Yoo <donggeunyoo.kernel@gmail.com> mainline inclusion from mainline-v7.3-rc3 commit 6ede78d0563a2a3ae3e46f9c07cedb5d79645429 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/20176 CVE: CVE-2026-97935 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- hist_register_trigger() puts the trigger on the global named_triggers list in cmd_ops->init(), and only then sets the trace clock: if (data->cmd_ops->init) { ret = data->cmd_ops->init(data); if (ret < 0) goto out; } if (hist_data->enable_timestamps) { ret = tracing_set_clock(file->tr, hist_data->attrs->clock); if (ret) { hist_err(tr, HIST_ERR_SET_CLOCK_FAIL, errpos(clock)); goto out; } The clock string is not checked anywhere before that call, so a named trigger using common_timestamp with an unknown clock fails after it has already become findable. event_hist_trigger_parse() then frees it without taking it off the list, and the next lookup by name reads the freed object: ~# cd /sys/kernel/tracing/events/sched/sched_switch ~# echo 'hist:name=foo:keys=common_pid:ts=common_timestamp:clock=bogus' > trigger bash: echo: write error: Invalid argument ~# echo 'hist:name=foo:keys=common_pid' > trigger BUG: KASAN: slab-use-after-free in find_named_trigger+0xac/0xc0 Read of size 8 at addr ffff88800915d760 by task init/1 find_named_trigger+0xac/0xc0 hist_register_trigger+0xc1/0x900 event_hist_trigger_parse+0x3146/0x6af0 event_trigger_write+0xce/0x160 Freed by task 63: kfree+0x154/0x420 trigger_kthread_fn+0xfd/0x160 Set the clock before the trigger is registered, so that nothing which can fail runs after it is published, the way commit 6f86bdeab633 ("tracing: Fix bad hist from corrupting named_triggers list") moved the registration below the rest of the setup. tracing_set_filter_buffering() is reference counted, so the init failure path has to drop the reference that the clock block now takes first. Cc: stable@vger.kernel.org Fixes: a4072fe85ba3 ("tracing: Add a clock attribute for hist triggers") Link: https://patch.msgid.link/20260907091415.554535-1-donggeunyoo.kernel@gmail.co... Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Conflicts: kernel/trace/trace_events_hist.c [Two minimal adaptations are needed: 1) Replace cmd_ops with ops; 2) Replace tracing_set_filter_buffering with tracing_set_time_stamp_abs.] Signed-off-by: Tengda Wu <wutengda2@huawei.com> --- kernel/trace/trace_events_hist.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 557b8c28faf4..0fc7c59af276 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -5577,12 +5577,6 @@ static int hist_register_trigger(char *glob, struct event_trigger_ops *ops, data->ops = &event_hist_trigger_named_ops; } - if (data->ops->init) { - ret = data->ops->init(data->ops, data); - if (ret < 0) - goto out; - } - if (hist_data->enable_timestamps) { char *clock = hist_data->attrs->clock; @@ -5595,6 +5589,15 @@ static int hist_register_trigger(char *glob, struct event_trigger_ops *ops, tracing_set_time_stamp_abs(file->tr, true); } + if (data->ops->init) { + ret = data->ops->init(data->ops, data); + if (ret < 0) { + if (hist_data->enable_timestamps) + tracing_set_time_stamp_abs(file->tr, false); + goto out; + } + } + if (named_data) destroy_hist_data(hist_data); -- 2.34.1