6.6-stable review patch. If anyone has any objections, please let me know.
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From: Andreas Gruenbacher agruenba@redhat.com
[ Upstream commit 35264909e9d1973ab9aaa2a1b07cda70f12bb828 ]
In gfs2_jindex_free(), set sdp->sd_jdesc to NULL under the log flush lock to provide exclusion against gfs2_log_flush().
In gfs2_log_flush(), check if sdp->sd_jdesc is non-NULL before dereferencing it. Otherwise, we could run into a NULL pointer dereference when outstanding glock work races with an unmount (glock_work_func -> run_queue -> do_xmote -> inode_go_sync -> gfs2_log_flush).
Signed-off-by: Andreas Gruenbacher agruenba@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/gfs2/log.c | 3 ++- fs/gfs2/super.c | 4 ++++ 2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c index 88bc9b1b22650..767549066066c 100644 --- a/fs/gfs2/log.c +++ b/fs/gfs2/log.c @@ -1102,7 +1102,8 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags) lops_before_commit(sdp, tr); if (gfs2_withdrawing_or_withdrawn(sdp)) goto out_withdraw; - gfs2_log_submit_bio(&sdp->sd_jdesc->jd_log_bio, REQ_OP_WRITE); + if (sdp->sd_jdesc) + gfs2_log_submit_bio(&sdp->sd_jdesc->jd_log_bio, REQ_OP_WRITE); if (gfs2_withdrawing_or_withdrawn(sdp)) goto out_withdraw;
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c index 2e1d1eca4d14a..8b34c6cf9293f 100644 --- a/fs/gfs2/super.c +++ b/fs/gfs2/super.c @@ -67,9 +67,13 @@ void gfs2_jindex_free(struct gfs2_sbd *sdp) sdp->sd_journals = 0; spin_unlock(&sdp->sd_jindex_spin);
+ down_write(&sdp->sd_log_flush_lock); sdp->sd_jdesc = NULL; + up_write(&sdp->sd_log_flush_lock); + while (!list_empty(&list)) { jd = list_first_entry(&list, struct gfs2_jdesc, jd_list); + BUG_ON(jd->jd_log_bio); gfs2_free_journal_extents(jd); list_del(&jd->jd_list); iput(jd->jd_inode);