From: Edward McClanahan <emcclanahan@nvidia.com>
To: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
"groug@kaod.org" <groug@kaod.org>,
"jose.carlos.venegas.munoz@intel.com"
<jose.carlos.venegas.munoz@intel.com>,
"ma.mandourr@gmail.com" <ma.mandourr@gmail.com>,
"Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>
Cc: "virtio-fs@redhat.com" <virtio-fs@redhat.com>,
"vgoyal@redhat.com" <vgoyal@redhat.com>
Subject: Re: [Virtio-fs] [PULL 01/12] virtiofsd: Fix side-effect in assert()
Date: Thu, 6 May 2021 19:11:14 +0000 [thread overview]
Message-ID: <BY5PR12MB3809AA7700A873AEF4CCEB9AC5589@BY5PR12MB3809.namprd12.prod.outlook.com> (raw)
In-Reply-To: <20210506185641.284821-2-dgilbert@redhat.com>
[-- Attachment #1: Type: text/plain, Size: 4533 bytes --]
Very nice catch David... Countless times I've gotten bit by this one!
Get Outlook for Android<https://aka.ms/AAb9ysg>
________________________________
From: virtio-fs-bounces@redhat.com <virtio-fs-bounces@redhat.com> on behalf of Dr. David Alan Gilbert (git) <dgilbert@redhat.com>
Sent: Thursday, May 6, 2021 1:56:30 PM
To: qemu-devel@nongnu.org <qemu-devel@nongnu.org>; groug@kaod.org <groug@kaod.org>; jose.carlos.venegas.munoz@intel.com <jose.carlos.venegas.munoz@intel.com>; ma.mandourr@gmail.com <ma.mandourr@gmail.com>
Cc: virtio-fs@redhat.com <virtio-fs@redhat.com>; vgoyal@redhat.com <vgoyal@redhat.com>
Subject: [Virtio-fs] [PULL 01/12] virtiofsd: Fix side-effect in assert()
External email: Use caution opening links or attachments
From: Greg Kurz <groug@kaod.org>
It is bad practice to put an expression with a side-effect in
assert() because the side-effect won't happen if the code is
compiled with -DNDEBUG.
Use an intermediate variable. Consolidate this in an macro to
have proper line numbers when the assertion is hit.
virtiofsd: ../../tools/virtiofsd/passthrough_ll.c:2797: lo_getxattr:
Assertion `fchdir_res == 0' failed.
Aborted
2796 /* fchdir should not fail here */
=>2797 FCHDIR_NOFAIL(lo->proc_self_fd);
2798 ret = getxattr(procname, name, value, size);
2799 FCHDIR_NOFAIL(lo->root.fd);
Fixes: bdfd66788349 ("virtiofsd: Fix xattr operations")
Cc: misono.tomohiro@jp.fujitsu.com
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20210409100627.451573-1-groug@kaod.org>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
tools/virtiofsd/passthrough_ll.c | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)
diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
index 1553d2ef45..6592f96f68 100644
--- a/tools/virtiofsd/passthrough_ll.c
+++ b/tools/virtiofsd/passthrough_ll.c
@@ -2723,6 +2723,11 @@ static int xattr_map_server(const struct lo_data *lo, const char *server_name,
return -ENODATA;
}
+#define FCHDIR_NOFAIL(fd) do { \
+ int fchdir_res = fchdir(fd); \
+ assert(fchdir_res == 0); \
+ } while (0)
+
static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name,
size_t size)
{
@@ -2789,9 +2794,9 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name,
ret = fgetxattr(fd, name, value, size);
} else {
/* fchdir should not fail here */
- assert(fchdir(lo->proc_self_fd) == 0);
+ FCHDIR_NOFAIL(lo->proc_self_fd);
ret = getxattr(procname, name, value, size);
- assert(fchdir(lo->root.fd) == 0);
+ FCHDIR_NOFAIL(lo->root.fd);
}
if (ret == -1) {
@@ -2864,9 +2869,9 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size)
ret = flistxattr(fd, value, size);
} else {
/* fchdir should not fail here */
- assert(fchdir(lo->proc_self_fd) == 0);
+ FCHDIR_NOFAIL(lo->proc_self_fd);
ret = listxattr(procname, value, size);
- assert(fchdir(lo->root.fd) == 0);
+ FCHDIR_NOFAIL(lo->root.fd);
}
if (ret == -1) {
@@ -3000,9 +3005,9 @@ static void lo_setxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name,
ret = fsetxattr(fd, name, value, size, flags);
} else {
/* fchdir should not fail here */
- assert(fchdir(lo->proc_self_fd) == 0);
+ FCHDIR_NOFAIL(lo->proc_self_fd);
ret = setxattr(procname, name, value, size, flags);
- assert(fchdir(lo->root.fd) == 0);
+ FCHDIR_NOFAIL(lo->root.fd);
}
saverr = ret == -1 ? errno : 0;
@@ -3066,9 +3071,9 @@ static void lo_removexattr(fuse_req_t req, fuse_ino_t ino, const char *in_name)
ret = fremovexattr(fd, name);
} else {
/* fchdir should not fail here */
- assert(fchdir(lo->proc_self_fd) == 0);
+ FCHDIR_NOFAIL(lo->proc_self_fd);
ret = removexattr(procname, name);
- assert(fchdir(lo->root.fd) == 0);
+ FCHDIR_NOFAIL(lo->root.fd);
}
saverr = ret == -1 ? errno : 0;
--
2.31.1
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next prev parent reply other threads:[~2021-05-06 20:27 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-06 18:56 [PULL 00/12] virtiofs queue Dr. David Alan Gilbert (git)
2021-05-06 18:56 ` [PULL 01/12] virtiofsd: Fix side-effect in assert() Dr. David Alan Gilbert (git)
2021-05-06 19:11 ` Edward McClanahan [this message]
2021-05-06 18:56 ` [PULL 02/12] virtiofsd: Allow use "-o xattrmap" without "-o xattr" Dr. David Alan Gilbert (git)
2021-05-06 18:56 ` [PULL 03/12] virtiofsd: Add help for -o xattr-mapping Dr. David Alan Gilbert (git)
2021-05-06 18:56 ` [PULL 04/12] virtiofs: Fixup printf args Dr. David Alan Gilbert (git)
2021-05-06 18:56 ` [PULL 05/12] virtiofsd: Don't assume header layout Dr. David Alan Gilbert (git)
2021-05-06 18:56 ` [PULL 06/12] virtiofsd: Changed allocations of fuse_req to GLib functions Dr. David Alan Gilbert (git)
2021-05-06 18:56 ` [PULL 07/12] virtiofsd: Changed allocations of iovec to GLib's functions Dr. David Alan Gilbert (git)
2021-05-06 18:56 ` [PULL 08/12] virtiofsd: Changed allocations of fuse_session " Dr. David Alan Gilbert (git)
2021-05-06 18:56 ` [PULL 09/12] virtiofsd: Changed allocation of lo_map_elems " Dr. David Alan Gilbert (git)
2021-05-06 18:56 ` [PULL 10/12] virtiofsd: Changed allocations of fv_VuDev & its internals to GLib functions Dr. David Alan Gilbert (git)
2021-05-06 18:56 ` [PULL 11/12] virtiofsd/passthrough_ll.c: Changed local allocations " Dr. David Alan Gilbert (git)
2021-05-06 18:56 ` [PULL 12/12] virtiofsd/fuse_virtio.c: Changed allocations of locals to GLib Dr. David Alan Gilbert (git)
2021-05-11 15:05 ` [PULL 00/12] virtiofs queue Peter Maydell
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