This is a note to let you know that I've just added the patch titled taskstats: Cleanup the use of task->exit_code to the 5.16-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: taskstats-cleanup-the-use-of-task-exit_code.patch and it can be found in the queue-5.16 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 1b5a42d9c85f0e731f01c8d1129001fd8531a8a0 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> Date: Mon, 3 Jan 2022 11:32:36 -0600 Subject: taskstats: Cleanup the use of task->exit_code From: Eric W. Biederman <ebiederm@xxxxxxxxxxxx> commit 1b5a42d9c85f0e731f01c8d1129001fd8531a8a0 upstream. In the function bacct_add_task the code reading task->exit_code was introduced in commit f3cef7a99469 ("[PATCH] csa: basic accounting over taskstats"), and it is not entirely clear what the taskstats interface is trying to return as only returning the exit_code of the first task in a process doesn't make a lot of sense. As best as I can figure the intent is to return task->exit_code after a task exits. The field is returned with per task fields, so the exit_code of the entire process is not wanted. Only the value of the first task is returned so this is not a useful way to get the per task ptrace stop code. The ordinary case of returning this value is returning after a task exits, which also precludes use for getting a ptrace value. It is common to for the first task of a process to also be the last task of a process so this field may have done something reasonable by accident in testing. Make ac_exitcode a reliable per task value by always returning it for every exited task. Setting ac_exitcode in a sensible mannter makes it possible to continue to provide this value going forward. Cc: Balbir Singh <bsingharora@xxxxxxxxx> Fixes: f3cef7a99469 ("[PATCH] csa: basic accounting over taskstats") Link: https://lkml.kernel.org/r/20220103213312.9144-5-ebiederm@xxxxxxxxxxxx Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/tsacct.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- a/kernel/tsacct.c +++ b/kernel/tsacct.c @@ -38,11 +38,10 @@ void bacct_add_tsk(struct user_namespace stats->ac_btime = clamp_t(time64_t, btime, 0, U32_MAX); stats->ac_btime64 = btime; - if (thread_group_leader(tsk)) { + if (tsk->flags & PF_EXITING) stats->ac_exitcode = tsk->exit_code; - if (tsk->flags & PF_FORKNOEXEC) - stats->ac_flag |= AFORK; - } + if (thread_group_leader(tsk) && (tsk->flags & PF_FORKNOEXEC)) + stats->ac_flag |= AFORK; if (tsk->flags & PF_SUPERPRIV) stats->ac_flag |= ASU; if (tsk->flags & PF_DUMPCORE) Patches currently in stable-queue which might be from ebiederm@xxxxxxxxxxxx are queue-5.16/signal-in-get_signal-test-for-signal_group_exit-ever.patch queue-5.16/taskstats-cleanup-the-use-of-task-exit_code.patch queue-5.16/mlxsw-pci-add-shutdown-method-in-pci-driver.patch queue-5.16/netns-add-schedule-point-in-ops_exit_list.patch