From: Eric W. Biederman Date: Thu, 30 Apr 2020 11:43:44 +0000 (-0500) Subject: posix-cpu-timers: Use pids not tasks in lookup X-Git-Tag: v5.15~3582^2~3 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=2dd8083f6d8acd1371ccabedef1c9f1ad272a90d;p=platform%2Fkernel%2Flinux-starfive.git posix-cpu-timers: Use pids not tasks in lookup The current posix-cpu-timer code uses pids when holding persistent references in timers. However the lookups from clock_id_t still return tasks that need to be converted into pids for use. This results in usage being pid->task->pid and that can race with release_task and de_thread. This can lead to some not wrong but surprising results. Surprising enough that Oleg and I both thought there were some bugs in the code for a while. This set of changes modifies the code to just lookup, verify, and return pids from the clockid_t lookups to remove those potentialy troublesome races. Eric W. Biederman (3): posix-cpu-timers: Extend rcu_read_lock removing task_struct references posix-cpu-timers: Replace cpu_timer_pid_type with clock_pid_type posix-cpu-timers: Replace __get_task_for_clock with pid_for_clock kernel/time/posix-cpu-timers.c | 102 ++++++++++++++++++----------------------- 1 file changed, 45 insertions(+), 57 deletions(-) Suggested-by: Oleg Nesterov Signed-off-by: "Eric W. Biederman" --- 2dd8083f6d8acd1371ccabedef1c9f1ad272a90d