The quilt patch titled Subject: getrusage: move thread_group_cputime_adjusted() outside of lock_task_sighand() has been removed from the -mm tree. Its filename was getrusage-move-thread_group_cputime_adjusted-outside-of-lock_task_sighand.patch

This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------ From: Oleg Nesterov oleg@redhat.com Subject: getrusage: move thread_group_cputime_adjusted() outside of lock_task_sighand() Date: Mon, 22 Jan 2024 16:50:50 +0100

Patch series "getrusage: use sig->stats_lock", v2.

This patch (of 2):

thread_group_cputime() does its own locking, we can safely shift thread_group_cputime_adjusted() which does another for_each_thread loop outside of ->siglock protected section.

This is also preparation for the next patch which changes getrusage() to use stats_lock instead of siglock, thread_group_cputime() takes the same lock. With the current implementation recursive read_seqbegin_or_lock() is fine, thread_group_cputime() can't enter the slow mode if the caller holds stats_lock, yet this looks more safe and better performance-wise.

Link: https://lkml.kernel.org/r/20240122155023.GA26169@redhat.com Link: https://lkml.kernel.org/r/20240122155050.GA26205@redhat.com Signed-off-by: Oleg Nesterov oleg@redhat.com Reported-by: Dylan Hatch dylanbhatch@google.com Tested-by: Dylan Hatch dylanbhatch@google.com Cc: Eric W. Biederman ebiederm@xmission.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

kernel/sys.c | 36 ++++++++++++++++++++---------------- 1 file changed, 20 insertions(+), 16 deletions(-)

--- a/kernel/sys.c~getrusage-move-thread_group_cputime_adjusted-outside-of-lock_task_sighand +++ a/kernel/sys.c @@ -1785,17 +1785,19 @@ void getrusage(struct task_struct *p, in struct task_struct *t; unsigned long flags; u64 tgutime, tgstime, utime, stime; - unsigned long maxrss = 0; + unsigned long maxrss; + struct mm_struct *mm; struct signal_struct *sig = p->signal;

- memset((char *)r, 0, sizeof (*r)); + memset(r, 0, sizeof(*r)); utime = stime = 0; + maxrss = 0;

if (who == RUSAGE_THREAD) { task_cputime_adjusted(current, &utime, &stime); accumulate_thread_rusage(p, r); maxrss = sig->maxrss; - goto out; + goto out_thread; }

if (!lock_task_sighand(p, &flags)) @@ -1819,9 +1821,6 @@ void getrusage(struct task_struct *p, in fallthrough;

case RUSAGE_SELF: - thread_group_cputime_adjusted(p, &tgutime, &tgstime); - utime += tgutime; - stime += tgstime; r->ru_nvcsw += sig->nvcsw; r->ru_nivcsw += sig->nivcsw; r->ru_minflt += sig->min_flt; @@ -1839,19 +1838,24 @@ void getrusage(struct task_struct *p, in } unlock_task_sighand(p, &flags);

-out: - r->ru_utime = ns_to_kernel_old_timeval(utime); - r->ru_stime = ns_to_kernel_old_timeval(stime); - - if (who != RUSAGE_CHILDREN) { - struct mm_struct *mm = get_task_mm(p); + if (who == RUSAGE_CHILDREN) + goto out_children;

- if (mm) { - setmax_mm_hiwater_rss(&maxrss, mm); - mmput(mm); - } + thread_group_cputime_adjusted(p, &tgutime, &tgstime); + utime += tgutime; + stime += tgstime; + +out_thread: + mm = get_task_mm(p); + if (mm) { + setmax_mm_hiwater_rss(&maxrss, mm); + mmput(mm); } + +out_children: r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */ + r->ru_utime = ns_to_kernel_old_timeval(utime); + r->ru_stime = ns_to_kernel_old_timeval(stime); }

SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru) _

Patches currently in -mm which might be from oleg@redhat.com are

ptrace_attach-shift-sendsigstop-into-ptrace_set_stopped.patch