Author: cem Date: Sun Aug 2 16:34:27 2020 New Revision: 363770 URL: https://svnweb.freebsd.org/changeset/base/363770
Log: Unlocked getblk: Fix new false-positive assertion A free buf's lock may be held (temporarily) due to unlocked lookup, so buf_alloc() must acquire it without LK_NOWAIT. The unlocked getblk path should unlock it promptly once it realizes the identity does not match the buffer it was searching for. Reported by: gallatin Reviewed by: kib Tested by: pho X-MFC-With: r363482 Sponsored by: Dell EMC Isilon Differential Revision: https://reviews.freebsd.org/D25914 Modified: head/sys/kern/vfs_bio.c Modified: head/sys/kern/vfs_bio.c ============================================================================== --- head/sys/kern/vfs_bio.c Sun Aug 2 04:25:36 2020 (r363769) +++ head/sys/kern/vfs_bio.c Sun Aug 2 16:34:27 2020 (r363770) @@ -1637,7 +1637,7 @@ static struct buf * buf_alloc(struct bufdomain *bd) { struct buf *bp; - int freebufs; + int freebufs, error; /* * We can only run out of bufs in the buf zone if the average buf @@ -1660,8 +1660,10 @@ buf_alloc(struct bufdomain *bd) if (freebufs == bd->bd_lofreebuffers) bufspace_daemon_wakeup(bd); - if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL) != 0) - panic("getnewbuf_empty: Locked buf %p on free queue.", bp); + error = BUF_LOCK(bp, LK_EXCLUSIVE, NULL); + KASSERT(error == 0, ("%s: BUF_LOCK on free buf %p: %d.", __func__, bp, + error)); + (void)error; KASSERT(bp->b_vp == NULL, ("bp: %p still has vnode %p.", bp, bp->b_vp)); _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
