From 20265d9a67e40eafd39a8884658ca2e36f05985d Mon Sep 17 00:00:00 2001 From: Bob Peterson Date: Tue, 18 May 2021 09:12:10 -0400 Subject: [PATCH] gfs2: fix scheduling while atomic bug in glocks Before this patch, in the unlikely event that gfs2_glock_dq encountered a withdraw, it would do a wait_on_bit to wait for its journal to be recovered, but it never released the glock's spin_lock, which caused a scheduling-while-atomic error. This patch unlocks the lockref spin_lock before waiting for recovery. Fixes: 601ef0d52e96 ("gfs2: Force withdraw to replay journals and wait for it to finish") Cc: stable@vger.kernel.org # v5.7+ Reported-by: Alexander Aring Signed-off-by: Bob Peterson Signed-off-by: Andreas Gruenbacher --- fs/gfs2/glock.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index ea7fc5c641c7..8c547db210fb 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -1466,9 +1466,11 @@ void gfs2_glock_dq(struct gfs2_holder *gh) glock_blocked_by_withdraw(gl) && gh->gh_gl != sdp->sd_jinode_gl) { sdp->sd_glock_dqs_held++; + spin_unlock(&gl->gl_lockref.lock); might_sleep(); wait_on_bit(&sdp->sd_flags, SDF_WITHDRAW_RECOVERY, TASK_UNINTERRUPTIBLE); + spin_lock(&gl->gl_lockref.lock); } if (gh->gh_flags & GL_NOCACHE) handle_callback(gl, LM_ST_UNLOCKED, 0, false);