[PATCH 3/4] proc: io_accounting: Use new infrastructure to fix deadlocks in execve
From: Bernd Edlinger <hidden>
Date: 2020-03-10 17:45:58
Also in:
linux-doc, linux-fsdevel, linux-mm, lkml, stable
Subsystem:
filesystems (vfs and infrastructure), proc filesystem, the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
Possibly related (same subject, not in this thread)
- 2020-03-11 · Re: [PATCH 3/4] proc: io_accounting: Use new infrastructure to fix deadlocks in execve · Eric W. Biederman <hidden>
- 2020-03-10 · Re: [PATCH 3/4] proc: io_accounting: Use new infrastructure to fix deadlocks in execve · Eric W. Biederman <hidden>
- 2020-03-10 · Re: [PATCH 3/4] proc: io_accounting: Use new infrastructure to fix deadlocks in execve · Bernd Edlinger <hidden>
- 2020-03-10 · Re: [PATCH 3/4] proc: io_accounting: Use new infrastructure to fix deadlocks in execve · Eric W. Biederman <hidden>
This changes do_io_accounting to use the new exec_update_mutex instead of cred_guard_mutex. This fixes possible deadlocks when the trace is accessing /proc/$pid/io for instance. This should be safe, as the credentials are only used for reading. Signed-off-by: Bernd Edlinger <redacted> --- fs/proc/base.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 4fdfe4f..529d0c6 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c@@ -2770,7 +2770,7 @@ static int do_io_accounting(struct task_struct *task, struct seq_file *m, int wh unsigned long flags; int result; - result = mutex_lock_killable(&task->signal->cred_guard_mutex); + result = mutex_lock_killable(&task->signal->exec_update_mutex); if (result) return result;
@@ -2806,7 +2806,7 @@ static int do_io_accounting(struct task_struct *task, struct seq_file *m, int wh result = 0; out_unlock: - mutex_unlock(&task->signal->cred_guard_mutex); + mutex_unlock(&task->signal->exec_update_mutex); return result; }
--
1.9.1