gfs2: Fix unlikely race in gdlm_put_lock

[ Upstream commit 28c4d9bc07 ]

In gdlm_put_lock(), there is a small window of time in which the
DFL_UNMOUNT flag has been set but the lockspace hasn't been released,
yet.  In that window, dlm may still call gdlm_ast() and gdlm_bast().
To prevent it from dereferencing freed glock objects, only free the
glock if the lockspace has actually been released.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Andrew Price <anprice@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Andreas Gruenbacher
2025-08-06 23:34:03 +02:00
committed by Greg Kroah-Hartman
parent d35ed24aff
commit 64c61b4ac6

View File

@@ -361,12 +361,6 @@ static void gdlm_put_lock(struct gfs2_glock *gl)
gfs2_sbstats_inc(gl, GFS2_LKS_DCOUNT);
gfs2_update_request_times(gl);
/* don't want to call dlm if we've unmounted the lock protocol */
if (test_bit(DFL_UNMOUNT, &ls->ls_recover_flags)) {
gfs2_glock_free(gl);
return;
}
/*
* When the lockspace is released, all remaining glocks will be
* unlocked automatically. This is more efficient than unlocking them
@@ -396,6 +390,11 @@ again:
goto again;
}
if (error == -ENODEV) {
gfs2_glock_free(gl);
return;
}
if (error) {
fs_err(sdp, "gdlm_unlock %x,%llx err=%d\n",
gl->gl_name.ln_type,