The branch main has been updated by kib:
URL:
https://cgit.FreeBSD.org/src/commit/?id=5cc82c563eda97b70120f06e9635ab6c1c24fecd
commit 5cc82c563eda97b70120f06e9635ab6c1c24fecd
Author: Konstantin Belousov <k...@freebsd.org>
AuthorDate: 2021-09-02 04:04:23 +0000
Commit: Konstantin Belousov <k...@freebsd.org>
CommitDate: 2021-09-02 18:36:33 +0000
cluster_write(): do not access buffer after it is released
The issue was reported by
Alexander Lochmann <alexander.lochm...@tu-dortmund.de>,
who found the problem by performing lock analysis using LockDoc,
see https://doi.org/10.1145/3302424.3303948.
Reviewed by: mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D31780
---
sys/kern/vfs_cluster.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/sys/kern/vfs_cluster.c b/sys/kern/vfs_cluster.c
index 7ca67c390b91..d3b303f28f6b 100644
--- a/sys/kern/vfs_cluster.c
+++ b/sys/kern/vfs_cluster.c
@@ -646,7 +646,7 @@ void
cluster_write(struct vnode *vp, struct vn_clusterw *vnc, struct buf *bp,
u_quad_t filesize, int seqcount, int gbflags)
{
- daddr_t lbn;
+ daddr_t lbn, pbn;
int maxclen, cursize;
int lblocksize;
int async;
@@ -753,14 +753,16 @@ cluster_write(struct vnode *vp, struct vn_clusterw *vnc,
struct buf *bp,
bp->b_blkno == bp->b_lblkno &&
(VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen,
NULL) != 0 || bp->b_blkno == -1)) {
+ pbn = bp->b_blkno;
bawrite(bp);
vnc->v_clen = 0;
- vnc->v_lasta = bp->b_blkno;
+ vnc->v_lasta = pbn;
vnc->v_cstart = lbn + 1;
vnc->v_lastw = lbn;
return;
}
vnc->v_clen = maxclen;
+ pbn = bp->b_blkno;
if (!async && maxclen == 0) { /* I/O not contiguous */
vnc->v_cstart = lbn + 1;
bawrite(bp);
@@ -774,6 +776,7 @@ cluster_write(struct vnode *vp, struct vn_clusterw *vnc,
struct buf *bp,
* are operating sequentially, otherwise let the buf or
* update daemon handle it.
*/
+ pbn = bp->b_blkno;
bdwrite(bp);
if (seqcount > 1) {
cluster_wbuild_wb(vp, lblocksize, vnc->v_cstart,
@@ -785,15 +788,17 @@ cluster_write(struct vnode *vp, struct vn_clusterw *vnc,
struct buf *bp,
/*
* We are low on memory, get it going NOW
*/
+ pbn = bp->b_blkno;
bawrite(bp);
} else {
/*
* In the middle of a cluster, so just delay the I/O for now.
*/
+ pbn = bp->b_blkno;
bdwrite(bp);
}
vnc->v_lastw = lbn;
- vnc->v_lasta = bp->b_blkno;
+ vnc->v_lasta = pbn;
}
/*
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