From: MengEn Sun <mengensun@tencent.com> mainline inclusion from mainline-v6.14-rc1 commit f49b42d415a32faee6bc08923821f432f64a4e90 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IC97W5 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ---------------------------------------------------------------------- Although kfree is a non-sleep function, it is possible to enter a long chain of calls probabilistically, so it looks better to move kfree from alloc_ucounts() out of the critical zone of ucounts_lock. Link: https://lkml.kernel.org/r/1733458427-11794-1-git-send-email-mengensun@tencen... Signed-off-by: MengEn Sun <mengensun@tencent.com> Reviewed-by: YueHong Wu <yuehongwu@tencent.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Andrei Vagin <avagin@google.com> Cc: Joel Granados <joel.granados@kernel.org> Cc: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Chen Ridong <chenridong@huawei.com> --- kernel/ucount.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/kernel/ucount.c b/kernel/ucount.c index 584b73807c445..2c929c6c4784c 100644 --- a/kernel/ucount.c +++ b/kernel/ucount.c @@ -169,8 +169,8 @@ struct ucounts *get_ucounts(struct ucounts *ucounts) struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid) { struct hlist_head *hashent = ucounts_hashentry(ns, uid); - struct ucounts *ucounts, *new; bool wrapped; + struct ucounts *ucounts, *new = NULL; spin_lock_irq(&ucounts_lock); ucounts = find_ucounts(ns, uid, hashent); @@ -187,17 +187,17 @@ struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid) spin_lock_irq(&ucounts_lock); ucounts = find_ucounts(ns, uid, hashent); - if (ucounts) { - kfree(new); - } else { + if (!ucounts) { hlist_add_head(&new->node, hashent); get_user_ns(new->ns); spin_unlock_irq(&ucounts_lock); return new; } } + wrapped = !get_ucounts_or_wrap(ucounts); spin_unlock_irq(&ucounts_lock); + kfree(new); if (wrapped) { put_ucounts(ucounts); return NULL; -- 2.34.1