On Thu, Jul 10, 2025 at 12:35:43PM +0000, Heyne, Maximilian wrote: > From: Oleg Nesterov <oleg@xxxxxxxxxx> > > [ Upstream commit 7904e53ed5a20fc678c01d5d1b07ec486425bb6a ] > > do/while_each_thread should be avoided when possible. > > Link: https://lkml.kernel.org/r/20230909164501.GA11581@xxxxxxxxxx > Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> > Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Stable-dep-of: 7601df8031fd ("fs/proc: do_task_stat: use sig->stats_lock to gather the threads/children stats") > Cc: stable@xxxxxxxxxxxxxxx > [mheyne: adjusted context] > Signed-off-by: Maximilian Heyne <mheyne@xxxxxxxxx> > --- > > Compile-tested only. > We're seeing soft lock-ups with 5.10.237 because of the backport of > commit 4fe85bdaabd6 ("fs/proc: do_task_stat: use sig->stats_lock to > gather the threads/children stats"). And this fixes it? How? > > --- > fs/proc/array.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/fs/proc/array.c b/fs/proc/array.c > index 8fba6d39e776..77b94c04e4af 100644 > --- a/fs/proc/array.c > +++ b/fs/proc/array.c > @@ -512,18 +512,18 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, > cgtime = sig->cgtime; > > if (whole) { > - struct task_struct *t = task; > + struct task_struct *t; > > min_flt = sig->min_flt; > maj_flt = sig->maj_flt; > gtime = sig->gtime; > > rcu_read_lock(); > - do { > + __for_each_thread(sig, t) { > min_flt += t->min_flt; > maj_flt += t->maj_flt; > gtime += task_gtime(t); > - } while_each_thread(task, t); > + } Ideally, the code generated here should be identical as before, so why is this change needed? confused, greg k-h
