Please pull the proc-linus branch from the git tree:
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace.git proc-linus HEAD: 058f2e4da79b23afb56ce3d03d907d6cdd36f2b8 proc: s_fs_info may be NULL when proc_kill_sb is called Syzbot found a NULL pointer dereference if kzalloc of proc's s_fs_info fails. The fix is the patch below. --- From: Alexey Gladkov <[email protected]> Date: Wed, 10 Jun 2020 20:35:49 +0200 Subject: [PATCH] proc: s_fs_info may be NULL when proc_kill_sb is called syzbot found that proc_fill_super() fails before filling up sb->s_fs_info, deactivate_locked_super() will be called and sb->s_fs_info will be NULL. The proc_kill_sb() does not expect fs_info to be NULL which is wrong. Link: https://lore.kernel.org/lkml/[email protected] Reported-by: [email protected] Fixes: fa10fed30f25 ("proc: allow to mount many instances of proc in one pid namespace") Signed-off-by: Alexey Gladkov <[email protected]> Signed-off-by: Eric W. Biederman <[email protected]> --- fs/proc/root.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/fs/proc/root.c b/fs/proc/root.c index ffebed1999e5..5e444d4f9717 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -264,11 +264,13 @@ static void proc_kill_sb(struct super_block *sb) { struct proc_fs_info *fs_info = proc_sb_info(sb); - if (fs_info->proc_self) - dput(fs_info->proc_self); + if (!fs_info) { + kill_anon_super(sb); + return; + } - if (fs_info->proc_thread_self) - dput(fs_info->proc_thread_self); + dput(fs_info->proc_self); + dput(fs_info->proc_thread_self); kill_anon_super(sb); put_pid_ns(fs_info->pid_ns); -- 2.20.1
