The branch main has been updated by kib:
URL:
https://cgit.FreeBSD.org/src/commit/?id=701b36961cbd2084c36eb828402d0ef89211d929
commit 701b36961cbd2084c36eb828402d0ef89211d929
Author: Konstantin Belousov <k...@freebsd.org>
AuthorDate: 2022-12-28 18:14:52 +0000
Commit: Konstantin Belousov <k...@freebsd.org>
CommitDate: 2022-12-29 20:55:39 +0000
ufs/suspend: deny suspension if the calling process has a file from mp
opened for write
Also deny suspension if we cannot check the above condition race-free
because there is more than one thread in the calling process.
PR: 267628, 267630
Reviewed by: mckusick
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D37896
---
sys/ufs/ffs/ffs_suspend.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/sys/ufs/ffs/ffs_suspend.c b/sys/ufs/ffs/ffs_suspend.c
index e7c976b6e921..a68f25d5eed2 100644
--- a/sys/ufs/ffs/ffs_suspend.c
+++ b/sys/ufs/ffs/ffs_suspend.c
@@ -36,6 +36,7 @@ __FBSDID("$FreeBSD$");
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/conf.h>
+#include <sys/filedesc.h>
#include <sys/ioccom.h>
#include <sys/jail.h>
#include <sys/mount.h>
@@ -302,6 +303,16 @@ ffs_susp_ioctl(struct cdev *dev, u_long cmd, caddr_t addr,
int flags,
vfs_rel(mp);
if (error != 0)
break;
+
+ /*
+ * Require single-thread curproc so that the check is not racey.
+ * XXXKIB: might consider to singlethread curproc instead.
+ */
+ error = curproc->p_numthreads > 1 ? EDEADLK :
+ descrip_check_write_mp(curproc->p_fd, mp);
+ if (error != 0)
+ break;
+
error = ffs_susp_suspend(mp);
if (error != 0) {
vfs_unbusy(mp);
