Module Name: src
Committed By: hannken
Date: Sat Mar 26 14:58:13 UTC 2016
Modified Files:
src/sys/miscfs/specfs: spec_vnops.c
Log Message:
Whhen spec_strategy() extracts v_rdev take care to avoid a
race with spec_revoke.
Fixes PR kern/50467 Panic from disconnecting phone while reading its contents
To generate a diff of this commit:
cvs rdiff -u -r1.160 -r1.161 src/sys/miscfs/specfs/spec_vnops.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/miscfs/specfs/spec_vnops.c
diff -u src/sys/miscfs/specfs/spec_vnops.c:1.160 src/sys/miscfs/specfs/spec_vnops.c:1.161
--- src/sys/miscfs/specfs/spec_vnops.c:1.160 Tue Jan 5 09:07:19 2016
+++ src/sys/miscfs/specfs/spec_vnops.c Sat Mar 26 14:58:13 2016
@@ -1,4 +1,4 @@
-/* $NetBSD: spec_vnops.c,v 1.160 2016/01/05 09:07:19 pgoyette Exp $ */
+/* $NetBSD: spec_vnops.c,v 1.161 2016/03/26 14:58:13 hannken Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -58,7 +58,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: spec_vnops.c,v 1.160 2016/01/05 09:07:19 pgoyette Exp $");
+__KERNEL_RCSID(0, "$NetBSD: spec_vnops.c,v 1.161 2016/03/26 14:58:13 hannken Exp $");
#include <sys/param.h>
#include <sys/proc.h>
@@ -1029,26 +1029,45 @@ spec_strategy(void *v)
} */ *ap = v;
struct vnode *vp = ap->a_vp;
struct buf *bp = ap->a_bp;
+ dev_t dev;
int error;
- KASSERT(vp == vp->v_specnode->sn_dev->sd_bdevvp);
+ dev = NODEV;
- error = 0;
- bp->b_dev = vp->v_rdev;
+ /*
+ * Extract all the info we need from the vnode, taking care to
+ * avoid a race with VOP_REVOKE().
+ */
- if (!(bp->b_flags & B_READ))
- error = fscow_run(bp, false);
+ mutex_enter(vp->v_interlock);
+ if (vdead_check(vp, VDEAD_NOWAIT) == 0 && vp->v_specnode != NULL) {
+ dev = vp->v_rdev;
+ }
+ mutex_exit(vp->v_interlock);
- if (error) {
- bp->b_error = error;
- bp->b_resid = bp->b_bcount;
- biodone(bp);
- return (error);
+ if (dev == NODEV) {
+ error = ENXIO;
+ goto out;
}
+ bp->b_dev = dev;
+ KASSERT(vp == vp->v_specnode->sn_dev->sd_bdevvp);
+
+ if (!(bp->b_flags & B_READ)) {
+ error = fscow_run(bp, false);
+ if (error)
+ goto out;
+ }
bdev_strategy(bp);
- return (0);
+ return 0;
+
+out:
+ bp->b_error = error;
+ bp->b_resid = bp->b_bcount;
+ biodone(bp);
+
+ return error;
}
int
