From 74b4dbb946060a3233604d91859a9abd3708141d Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Tue, 7 Apr 2026 12:14:30 +0200 Subject: [PATCH] gfs2: prevent NULL pointer dereference during unmount When flushing out outstanding glock work during an unmount, gfs2_log_flush() can be called when sdp->sd_jdesc has already been deallocated and sdp->sd_jdesc is NULL. Commit 35264909e9d1 ("gfs2: Fix NULL pointer dereference in gfs2_log_flush") added a check for that to gfs2_log_flush() itself, but it missed the sdp->sd_jdesc dereference in gfs2_log_release(). Fix that. Reported-by: kernel test robot Reported-by: Dan Carpenter Closes: https://lore.kernel.org/r/202604071139.HNJiCaAi-lkp@intel.com/ Fixes: 35264909e9d1 ("gfs2: Fix NULL pointer dereference in gfs2_log_flush") Signed-off-by: Andreas Gruenbacher --- fs/gfs2/log.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c index 3a01d4e7667a..78bba8cc10b8 100644 --- a/fs/gfs2/log.c +++ b/fs/gfs2/log.c @@ -467,8 +467,9 @@ void gfs2_log_release(struct gfs2_sbd *sdp, unsigned int blks) { atomic_add(blks, &sdp->sd_log_blks_free); trace_gfs2_log_blocks(sdp, blks); - gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <= - sdp->sd_jdesc->jd_blocks); + gfs2_assert_withdraw(sdp, !sdp->sd_jdesc || + atomic_read(&sdp->sd_log_blks_free) <= + sdp->sd_jdesc->jd_blocks); if (atomic_read(&sdp->sd_log_blks_needed)) wake_up(&sdp->sd_log_waitq); }