| Commit message (Collapse) | Author | Age | Files | Lines |
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Rework io_uring_del_task_file(), so it accepts an index to delete, and
it's not necessarily have to be in the ->xa. Infer file from xa_erase()
to maintain a single origin of truth.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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If we go async with a request, grab the creds that the task currently has
assigned and make sure that the async side switches to them. This is
handled in the same way that we do for registered personalities.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Ran into a use-after-free on the main io-wq struct, wq. It has a worker
ref and completion event, but the manager itself isn't holding a
reference. This can lead to a race where the manager thinks there are
no workers and exits, but a worker is being added. That leads to the
following trace:
BUG: KASAN: use-after-free in io_wqe_worker+0x4c0/0x5e0
Read of size 8 at addr ffff888108baa8a0 by task iou-wrk-3080422/3080425
CPU: 5 PID: 3080425 Comm: iou-wrk-3080422 Not tainted 5.12.0-rc1+ #110
Hardware name: Micro-Star International Co., Ltd. MS-7C60/TRX40 PRO 10G (MS-7C60), BIOS 1.60 05/13/2020
Call Trace:
dump_stack+0x90/0xbe
print_address_description.constprop.0+0x67/0x28d
? io_wqe_worker+0x4c0/0x5e0
kasan_report.cold+0x7b/0xd4
? io_wqe_worker+0x4c0/0x5e0
__asan_load8+0x6d/0xa0
io_wqe_worker+0x4c0/0x5e0
? io_worker_handle_work+0xc00/0xc00
? recalc_sigpending+0xe5/0x120
? io_worker_handle_work+0xc00/0xc00
? io_worker_handle_work+0xc00/0xc00
ret_from_fork+0x1f/0x30
Allocated by task 3080422:
kasan_save_stack+0x23/0x60
__kasan_kmalloc+0x80/0xa0
kmem_cache_alloc_node_trace+0xa0/0x480
io_wq_create+0x3b5/0x600
io_uring_alloc_task_context+0x13c/0x380
io_uring_add_task_file+0x109/0x140
__x64_sys_io_uring_enter+0x45f/0x660
do_syscall_64+0x32/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Freed by task 3080422:
kasan_save_stack+0x23/0x60
kasan_set_track+0x20/0x40
kasan_set_free_info+0x24/0x40
__kasan_slab_free+0xe8/0x120
kfree+0xa8/0x400
io_wq_put+0x14a/0x220
io_wq_put_and_exit+0x9a/0xc0
io_uring_clean_tctx+0x101/0x140
__io_uring_files_cancel+0x36e/0x3c0
do_exit+0x169/0x1340
__x64_sys_exit+0x34/0x40
do_syscall_64+0x32/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Have the manager itself hold a reference, and now both drop points drop
and complete if we hit zero, and the manager can unconditionally do a
wait_for_completion() instead of having a race between reading the ref
count and waiting if it was non-zero.
Fixes: fb3a1f6c745c ("io-wq: have manager wait for all workers to exit")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Pull configfs fix from Christoph Hellwig:
- fix a use-after-free in __configfs_open_file (Daiyue Zhang)
* tag 'configfs-for-5.12' of git://git.infradead.org/users/hch/configfs:
configfs: fix a use-after-free in __configfs_open_file
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Commit b0841eefd969 ("configfs: provide exclusion between IO and removals")
uses ->frag_dead to mark the fragment state, thus no bothering with extra
refcount on config_item when opening a file. The configfs_get_config_item
was removed in __configfs_open_file, but not with config_item_put. So the
refcount on config_item will lost its balance, causing use-after-free
issues in some occasions like this:
Test:
1. Mount configfs on /config with read-only items:
drwxrwx--- 289 root root 0 2021-04-01 11:55 /config
drwxr-xr-x 2 root root 0 2021-04-01 11:54 /config/a
--w--w--w- 1 root root 4096 2021-04-01 11:53 /config/a/1.txt
......
2. Then run:
for file in /config
do
echo $file
grep -R 'key' $file
done
3. __configfs_open_file will be called in parallel, the first one
got called will do:
if (file->f_mode & FMODE_READ) {
if (!(inode->i_mode & S_IRUGO))
goto out_put_module;
config_item_put(buffer->item);
kref_put()
package_details_release()
kfree()
the other one will run into use-after-free issues like this:
BUG: KASAN: use-after-free in __configfs_open_file+0x1bc/0x3b0
Read of size 8 at addr fffffff155f02480 by task grep/13096
CPU: 0 PID: 13096 Comm: grep VIP: 00 Tainted: G W 4.14.116-kasan #1
TGID: 13096 Comm: grep
Call trace:
dump_stack+0x118/0x160
kasan_report+0x22c/0x294
__asan_load8+0x80/0x88
__configfs_open_file+0x1bc/0x3b0
configfs_open_file+0x28/0x34
do_dentry_open+0x2cc/0x5c0
vfs_open+0x80/0xe0
path_openat+0xd8c/0x2988
do_filp_open+0x1c4/0x2fc
do_sys_open+0x23c/0x404
SyS_openat+0x38/0x48
Allocated by task 2138:
kasan_kmalloc+0xe0/0x1ac
kmem_cache_alloc_trace+0x334/0x394
packages_make_item+0x4c/0x180
configfs_mkdir+0x358/0x740
vfs_mkdir2+0x1bc/0x2e8
SyS_mkdirat+0x154/0x23c
el0_svc_naked+0x34/0x38
Freed by task 13096:
kasan_slab_free+0xb8/0x194
kfree+0x13c/0x910
package_details_release+0x524/0x56c
kref_put+0xc4/0x104
config_item_put+0x24/0x34
__configfs_open_file+0x35c/0x3b0
configfs_open_file+0x28/0x34
do_dentry_open+0x2cc/0x5c0
vfs_open+0x80/0xe0
path_openat+0xd8c/0x2988
do_filp_open+0x1c4/0x2fc
do_sys_open+0x23c/0x404
SyS_openat+0x38/0x48
el0_svc_naked+0x34/0x38
To fix this issue, remove the config_item_put in
__configfs_open_file to balance the refcount of config_item.
Fixes: b0841eefd969 ("configfs: provide exclusion between IO and removals")
Signed-off-by: Daiyue Zhang <zhangdaiyue1@huawei.com>
Signed-off-by: Yi Chen <chenyi77@huawei.com>
Signed-off-by: Ge Qiu <qiuge@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
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git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
Pull gfs2 fixes from Andreas Gruenbacher:
"Various gfs2 fixes"
* tag 'gfs2-v5.12-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
gfs2: bypass log flush if the journal is not live
gfs2: bypass signal_our_withdraw if no journal
gfs2: fix use-after-free in trans_drain
gfs2: make function gfs2_make_fs_ro() to void type
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Patch fe3e397668775 ("gfs2: Rework the log space allocation logic")
changed gfs2_log_flush to reserve a set of journal blocks in case no
transaction is active. However, gfs2_log_flush also gets called in
cases where we don't have an active journal, for example, for spectator
mounts. In that case, trying to reserve blocks would sleep forever, but
we want gfs2_log_flush to be a no-op instead.
Fixes: fe3e397668775 ("gfs2: Rework the log space allocation logic")
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Before this patch, function signal_our_withdraw referenced the journal
inode immediately. But corrupt file systems may have some invalid
journals, in which case our attempt to read it in will withdraw and the
resulting signal_our_withdraw would dereference the NULL value.
This patch adds a check to signal_our_withdraw so that if the journal
has not yet been initialized, it simply returns and does the old-style
withdraw.
Thanks, Andy Price, for his analysis.
Reported-by: syzbot+50a8a9cf8127f2c6f5df@syzkaller.appspotmail.com
Fixes: 601ef0d52e96 ("gfs2: Force withdraw to replay journals and wait for it to finish")
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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This patch adds code to function trans_drain to remove drained
bd elements from the ail lists, if queued, before freeing the bd.
If we don't remove the bd from the ail, function ail_drain will
try to reference the bd after it has been freed by trans_drain.
Thanks to Andy Price for his analysis of the problem.
Reported-by: Andy Price <anprice@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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It fixes the following warning detected by coccinelle:
./fs/gfs2/super.c:592:5-10: Unneeded variable: "error". Return "0" on
line 628
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 fixes from Heiko Carstens:
- fix various user space visible copy_to_user() instances which return
the number of bytes left to copy instead of -EFAULT
- make TMPFS_INODE64 available again for s390 and alpha, now that both
architectures have been switched to 64-bit ino_t (see commit
96c0a6a72d18: "s390,alpha: switch to 64-bit ino_t")
- make sure to release a shared hypervisor resource within the zcore
device driver also on restart and power down; also remove unneeded
surrounding debugfs_create return value checks
- for the new hardware counter set device driver rename the uapi header
file to be a bit more generic; also remove 60 second read limit which
is not really necessary and without the limit the interface can be
easier tested
- some small cleanups, the largest being to convert all long long in
our time and idle code to longs
- update defconfigs
* tag 's390-5.12-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390: remove IBM_PARTITION and CONFIGFS_FS from zfcpdump defconfig
s390: update defconfigs
s390,alpha: make TMPFS_INODE64 available again
s390/cio: return -EFAULT if copy_to_user() fails
s390/tty3270: avoid comma separated statements
s390/cpumf: remove unneeded semicolon
s390/crypto: return -EFAULT if copy_to_user() fails
s390/cio: return -EFAULT if copy_to_user() fails
s390/cpumf: rename header file to hwctrset.h
s390/zcore: release dump save area on restart or power down
s390/zcore: no need to check return value of debugfs_create functions
s390/cpumf: remove 60 seconds read limit
s390/topology: remove always false if check
s390/time,idle: get rid of unsigned long long
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Both s390 and alpha have been switched to 64-bit ino_t with
commit 96c0a6a72d18 ("s390,alpha: switch to 64-bit ino_t").
Therefore enable TMPFS_INODE64 for both architectures again.
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Link: https://lore.kernel.org/linux-mm/YCV7QiyoweJwvN+m@osiris/
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull detached mounts fix from Christian Brauner:
"Creating a series of detached mounts, attaching them to the
filesystem, and unmounting them can be used to trigger an integer
overflow in ns->mounts causing the kernel to block any new mounts in
count_mounts() and returning ENOSPC because it falsely assumes that
the maximum number of mounts in the mount namespace has been reached,
i.e. it thinks it can't fit the new mounts into the mount namespace
anymore.
Without this fix heavy use of the new mount API with move_mount() will
cause the host to become unuseable and thus blocks some xfstest
patches I want to resend.
Depending on the number of mounts in your system, this can be
reproduced on any kernel that supportes open_tree() and move_mount().
A reproducer has been sent for inclusion with xfstests. It takes care
to do this in another mount namespace, not in the host's mount
namespace so there shouldn't be any risk in running it but if one did
run it on the host it would require a reboot in order to be able to
mount again. See
https://lore.kernel.org/fstests/20210309121041.753359-1-christian.brauner@ubuntu.com
The root cause of this is that detached mounts aren't handled
correctly when source and target mount are identical and reside on a
shared mount causing a broken mount tree where the detached source
itself is propagated which propagation prevents for regular
bind-mounts and new mounts.
This ultimately leads to a miscalculation of the number of mounts in
the mount namespace.
Detached mounts created via 'open_tree(fd, path, OPEN_TREE_CLONE)' are
essentially like an unattached bind-mount. They can then later on be
attached to the filesystem via move_mount() which calls into
attach_recursive_mount().
Part of attaching it to the filesystem is making sure that mounts get
correctly propagated in case the destination mountpoint is MS_SHARED,
i.e. is a shared mountpoint. This is done by calling into
propagate_mnt() which walks the list of peers calling propagate_one()
on each mount in this list making sure it receives the propagation
event. The propagate_one() function thereby skips both new mounts and
bind mounts to not propagate them "into themselves". Both are
identified by checking whether the mount is already attached to any
mount namespace in mnt->mnt_ns. The is what the IS_MNT_NEW() helper is
responsible for.
However, detached mounts have an anonymous mount namespace attached to
them stashed in mnt->mnt_ns which means that IS_MNT_NEW() doesn't
realize they need to be skipped causing the mount to propagate "into
itself" breaking the mount table and causing a disconnect between the
number of mounts recorded as being beneath or reachable from the
target mountpoint and the number of mounts actually recorded/counted
in ns->mounts ultimately causing an overflow which in turn prevents
any new mounts via the ENOSPC issue.
So teach propagation to handle detached mounts by making it aware of
them. I've been tracking this issue down for the last couple of days
and then verifying that the fix is correct by unmounting everything in
my current mount table leaving only /proc and /sys mounted and running
the reproducer above overnight verifying the number of mounts counted
in ns->mounts. With this fix the counts are correct and the ENOSPC
issue can't be reproduced.
This change will only have an effect on mounts created with the new
mount API since detached mounts cannot be created with the old mount
API so regressions are extremely unlikely.
Here's an illustration:
#### mount():
ubuntu@f1-vm:~$ sudo mount --bind /mnt/ /mnt/
ubuntu@f1-vm:~$ findmnt | grep -i mnt
├─/mnt /dev/sda2[/mnt] ext4 rw,relatime
#### open_tree(OPEN_TREE_CLONE) + move_mount() with bug:
ubuntu@f1-vm:~$ sudo ./mount-new /mnt/ /mnt/
ubuntu@f1-vm:~$ findmnt | grep -i mnt
├─/mnt /dev/sda2[/mnt] ext4 rw,relatime
│ └─/mnt /dev/sda2[/mnt] ext4 rw,relatime
#### open_tree(OPEN_TREE_CLONE) + move_mount() with the fix:
ubuntu@f1-vm:~$ sudo ./mount-new /mnt /mnt
ubuntu@f1-vm:~$ findmnt | grep -i mnt
└─/mnt /dev/sda2[/mnt] ext4 rw,relatime"
* tag 'for-linus-2021-03-10' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
mount: fix mounting of detached mounts onto targets that reside on shared mounts
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Creating a series of detached mounts, attaching them to the filesystem,
and unmounting them can be used to trigger an integer overflow in
ns->mounts causing the kernel to block any new mounts in count_mounts()
and returning ENOSPC because it falsely assumes that the maximum number
of mounts in the mount namespace has been reached, i.e. it thinks it
can't fit the new mounts into the mount namespace anymore.
Depending on the number of mounts in your system, this can be reproduced
on any kernel that supportes open_tree() and move_mount() by compiling
and running the following program:
/* SPDX-License-Identifier: LGPL-2.1+ */
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <unistd.h>
/* open_tree() */
#ifndef OPEN_TREE_CLONE
#define OPEN_TREE_CLONE 1
#endif
#ifndef OPEN_TREE_CLOEXEC
#define OPEN_TREE_CLOEXEC O_CLOEXEC
#endif
#ifndef __NR_open_tree
#if defined __alpha__
#define __NR_open_tree 538
#elif defined _MIPS_SIM
#if _MIPS_SIM == _MIPS_SIM_ABI32 /* o32 */
#define __NR_open_tree 4428
#endif
#if _MIPS_SIM == _MIPS_SIM_NABI32 /* n32 */
#define __NR_open_tree 6428
#endif
#if _MIPS_SIM == _MIPS_SIM_ABI64 /* n64 */
#define __NR_open_tree 5428
#endif
#elif defined __ia64__
#define __NR_open_tree (428 + 1024)
#else
#define __NR_open_tree 428
#endif
#endif
/* move_mount() */
#ifndef MOVE_MOUNT_F_EMPTY_PATH
#define MOVE_MOUNT_F_EMPTY_PATH 0x00000004 /* Empty from path permitted */
#endif
#ifndef __NR_move_mount
#if defined __alpha__
#define __NR_move_mount 539
#elif defined _MIPS_SIM
#if _MIPS_SIM == _MIPS_SIM_ABI32 /* o32 */
#define __NR_move_mount 4429
#endif
#if _MIPS_SIM == _MIPS_SIM_NABI32 /* n32 */
#define __NR_move_mount 6429
#endif
#if _MIPS_SIM == _MIPS_SIM_ABI64 /* n64 */
#define __NR_move_mount 5429
#endif
#elif defined __ia64__
#define __NR_move_mount (428 + 1024)
#else
#define __NR_move_mount 429
#endif
#endif
static inline int sys_open_tree(int dfd, const char *filename, unsigned int flags)
{
return syscall(__NR_open_tree, dfd, filename, flags);
}
static inline int sys_move_mount(int from_dfd, const char *from_pathname, int to_dfd,
const char *to_pathname, unsigned int flags)
{
return syscall(__NR_move_mount, from_dfd, from_pathname, to_dfd, to_pathname, flags);
}
static bool is_shared_mountpoint(const char *path)
{
bool shared = false;
FILE *f = NULL;
char *line = NULL;
int i;
size_t len = 0;
f = fopen("/proc/self/mountinfo", "re");
if (!f)
return 0;
while (getline(&line, &len, f) > 0) {
char *slider1, *slider2;
for (slider1 = line, i = 0; slider1 && i < 4; i++)
slider1 = strchr(slider1 + 1, ' ');
if (!slider1)
continue;
slider2 = strchr(slider1 + 1, ' ');
if (!slider2)
continue;
*slider2 = '\0';
if (strcmp(slider1 + 1, path) == 0) {
/* This is the path. Is it shared? */
slider1 = strchr(slider2 + 1, ' ');
if (slider1 && strstr(slider1, "shared:")) {
shared = true;
break;
}
}
}
fclose(f);
free(line);
return shared;
}
static void usage(void)
{
const char *text = "mount-new [--recursive] <base-dir>\n";
fprintf(stderr, "%s", text);
_exit(EXIT_SUCCESS);
}
#define exit_usage(format, ...) \
({ \
fprintf(stderr, format "\n", ##__VA_ARGS__); \
usage(); \
})
#define exit_log(format, ...) \
({ \
fprintf(stderr, format "\n", ##__VA_ARGS__); \
exit(EXIT_FAILURE); \
})
static const struct option longopts[] = {
{"help", no_argument, 0, 'a'},
{ NULL, no_argument, 0, 0 },
};
int main(int argc, char *argv[])
{
int exit_code = EXIT_SUCCESS, index = 0;
int dfd, fd_tree, new_argc, ret;
char *base_dir;
char *const *new_argv;
char target[PATH_MAX];
while ((ret = getopt_long_only(argc, argv, "", longopts, &index)) != -1) {
switch (ret) {
case 'a':
/* fallthrough */
default:
usage();
}
}
new_argv = &argv[optind];
new_argc = argc - optind;
if (new_argc < 1)
exit_usage("Missing base directory\n");
base_dir = new_argv[0];
if (*base_dir != '/')
exit_log("Please specify an absolute path");
/* Ensure that target is a shared mountpoint. */
if (!is_shared_mountpoint(base_dir))
exit_log("Please ensure that \"%s\" is a shared mountpoint", base_dir);
dfd = open(base_dir, O_RDONLY | O_DIRECTORY | O_CLOEXEC);
if (dfd < 0)
exit_log("%m - Failed to open base directory \"%s\"", base_dir);
ret = mkdirat(dfd, "detached-move-mount", 0755);
if (ret < 0)
exit_log("%m - Failed to create required temporary directories");
ret = snprintf(target, sizeof(target), "%s/detached-move-mount", base_dir);
if (ret < 0 || (size_t)ret >= sizeof(target))
exit_log("%m - Failed to assemble target path");
/*
* Having a mount table with 10000 mounts is already quite excessive
* and shoult account even for weird test systems.
*/
for (size_t i = 0; i < 10000; i++) {
fd_tree = sys_open_tree(dfd, "detached-move-mount",
OPEN_TREE_CLONE |
OPEN_TREE_CLOEXEC |
AT_EMPTY_PATH);
if (fd_tree < 0) {
fprintf(stderr, "%m - Failed to open %d(detached-move-mount)", dfd);
exit_code = EXIT_FAILURE;
break;
}
ret = sys_move_mount(fd_tree, "", dfd, "detached-move-mount", MOVE_MOUNT_F_EMPTY_PATH);
if (ret < 0) {
if (errno == ENOSPC)
fprintf(stderr, "%m - Buggy mount counting");
else
fprintf(stderr, "%m - Failed to attach mount to %d(detached-move-mount)", dfd);
exit_code = EXIT_FAILURE;
break;
}
close(fd_tree);
ret = umount2(target, MNT_DETACH);
if (ret < 0) {
fprintf(stderr, "%m - Failed to unmount %s", target);
exit_code = EXIT_FAILURE;
break;
}
}
(void)unlinkat(dfd, "detached-move-mount", AT_REMOVEDIR);
close(dfd);
exit(exit_code);
}
and wait for the kernel to refuse any new mounts by returning ENOSPC.
How many iterations are needed depends on the number of mounts in your
system. Assuming you have something like 50 mounts on a standard system
it should be almost instantaneous.
The root cause of this is that detached mounts aren't handled correctly
when source and target mount are identical and reside on a shared mount
causing a broken mount tree where the detached source itself is
propagated which propagation prevents for regular bind-mounts and new
mounts. This ultimately leads to a miscalculation of the number of
mounts in the mount namespace.
Detached mounts created via
open_tree(fd, path, OPEN_TREE_CLONE)
are essentially like an unattached new mount, or an unattached
bind-mount. They can then later on be attached to the filesystem via
move_mount() which calls into attach_recursive_mount(). Part of
attaching it to the filesystem is making sure that mounts get correctly
propagated in case the destination mountpoint is MS_SHARED, i.e. is a
shared mountpoint. This is done by calling into propagate_mnt() which
walks the list of peers calling propagate_one() on each mount in this
list making sure it receives the propagation event.
The propagate_one() functions thereby skips both new mounts and bind
mounts to not propagate them "into themselves". Both are identified by
checking whether the mount is already attached to any mount namespace in
mnt->mnt_ns. The is what the IS_MNT_NEW() helper is responsible for.
However, detached mounts have an anonymous mount namespace attached to
them stashed in mnt->mnt_ns which means that IS_MNT_NEW() doesn't
realize they need to be skipped causing the mount to propagate "into
itself" breaking the mount table and causing a disconnect between the
number of mounts recorded as being beneath or reachable from the target
mountpoint and the number of mounts actually recorded/counted in
ns->mounts ultimately causing an overflow which in turn prevents any new
mounts via the ENOSPC issue.
So teach propagation to handle detached mounts by making it aware of
them. I've been tracking this issue down for the last couple of days and
then verifying that the fix is correct by
unmounting everything in my current mount table leaving only /proc and
/sys mounted and running the reproducer above overnight verifying the
number of mounts counted in ns->mounts. With this fix the counts are
correct and the ENOSPC issue can't be reproduced.
This change will only have an effect on mounts created with the new
mount API since detached mounts cannot be created with the old mount API
so regressions are extremely unlikely.
Link: https://lore.kernel.org/r/20210306101010.243666-1-christian.brauner@ubuntu.com
Fixes: 2db154b3ea8e ("vfs: syscall: Add move_mount(2) to move mounts around")
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: <stable@vger.kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
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In case of interrupted syscalls, prevent sending CLOSE commands for
compound CREATE+CLOSE requests by introducing an
CIFS_CP_CREATE_CLOSE_OP flag to indicate lower layers that it should
not send a CLOSE command to the MIDs corresponding the compound
CREATE+CLOSE request.
A simple reproducer:
#!/bin/bash
mount //server/share /mnt -o username=foo,password=***
tc qdisc add dev eth0 root netem delay 450ms
stat -f /mnt &>/dev/null & pid=$!
sleep 0.01
kill $pid
tc qdisc del dev eth0 root
umount /mnt
Before patch:
...
6 0.256893470 192.168.122.2 → 192.168.122.15 SMB2 402 Create Request File: ;GetInfo Request FS_INFO/FileFsFullSizeInformation;Close Request
7 0.257144491 192.168.122.15 → 192.168.122.2 SMB2 498 Create Response File: ;GetInfo Response;Close Response
9 0.260798209 192.168.122.2 → 192.168.122.15 SMB2 146 Close Request File:
10 0.260841089 192.168.122.15 → 192.168.122.2 SMB2 130 Close Response, Error: STATUS_FILE_CLOSED
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
CC: <stable@vger.kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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In cifs_statfs(), if server->ops->queryfs is not NULL, then we should
use its return value rather than always returning 0. Instead, use rc
variable as it is properly set to 0 in case there is no
server->ops->queryfs.
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
CC: <stable@vger.kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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A customer has reported that their dmesg were being flooded by
CIFS: VFS: \\server Cancelling wait for mid xxx cmd: a
CIFS: VFS: \\server Cancelling wait for mid yyy cmd: b
CIFS: VFS: \\server Cancelling wait for mid zzz cmd: c
because some processes that were performing statfs(2) on the share had
been interrupted due to their automount setup when certain users
logged in and out.
Change it to FYI as they should be mostly informative rather than
error messages.
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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The MIDs are mostly printed as decimal, so let's make it consistent.
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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When doing a large read or write workload we only
very gradually increase the number of credits
which can cause problems with parallelizing large i/o
(I/O ramps up more slowly than it should for large
read/write workloads) especially with multichannel
when the number of credits on the secondary channels
starts out low (e.g. less than about 130) or when
recovering after server throttled back the number
of credit.
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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With multichannel, operations like the queries
from "ls -lR" can cause all credits to be used and
errors to be returned since max_credits was not
being set correctly on the secondary channels and
thus the client was requesting 0 credits incorrectly
in some cases (which can lead to not having
enough credits to perform any operation on that
channel).
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
CC: <stable@vger.kernel.org> # v5.8+
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull pstore fixes from Kees Cook:
- Rate-limit ECC warnings (Dmitry Osipenko)
- Fix error path check for NULL (Tetsuo Handa)
* tag 'pstore-v5.12-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
pstore/ram: Rate-limit "uncorrectable error in header" message
pstore: Fix warning in pstore_kill_sb()
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There is a quite huge "uncorrectable error in header" flood in KMSG
on a clean system boot since there is no pstore buffer saved in RAM.
Let's silence the redundant noisy messages by rate-limiting the printk
message. Now there are maximum 10 messages printed repeatedly instead
of 35+.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210302095850.30894-1-digetx@gmail.com
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syzbot is hitting WARN_ON(pstore_sb != sb) at pstore_kill_sb() [1], for the
assumption that pstore_sb != NULL is wrong because pstore_fill_super() will
not assign pstore_sb = sb when new_inode() for d_make_root() returned NULL
(due to memory allocation fault injection).
Since mount_single() calls pstore_kill_sb() when pstore_fill_super()
failed, pstore_kill_sb() needs to be aware of such failure path.
[1] https://syzkaller.appspot.com/bug?id=6abacb8da5137cb47a416f2bef95719ed60508a0
Reported-by: syzbot <syzbot+d0cf0ad6513e9a1da5df@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210214031307.57903-1-penguin-kernel@I-love.SAKURA.ne.jp
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Pull io_uring fixes from Jens Axboe:
"A bit of a mix between fallout from the worker change, cleanups and
reductions now possible from that change, and fixes in general. In
detail:
- Fully serialize manager and worker creation, fixing races due to
that.
- Clean up some naming that had gone stale.
- SQPOLL fixes.
- Fix race condition around task_work rework that went into this
merge window.
- Implement unshare. Used for when the original task does unshare(2)
or setuid/seteuid and friends, drops the original workers and forks
new ones.
- Drop the only remaining piece of state shuffling we had left, which
was cred. Move it into issue instead, and we can drop all of that
code too.
- Kill f_op->flush() usage. That was such a nasty hack that we had
out of necessity, we no longer need it.
- Following from ->flush() removal, we can also drop various bits of
ctx state related to SQPOLL and cancelations.
- Fix an issue with IOPOLL retry, which originally was fallout from a
filemap change (removing iov_iter_revert()), but uncovered an issue
with iovec re-import too late.
- Fix an issue with system suspend.
- Use xchg() for fallback work, instead of cmpxchg().
- Properly destroy io-wq on exec.
- Add create_io_thread() core helper, and use that in io-wq and
io_uring. This allows us to remove various silly completion events
related to thread setup.
- A few error handling fixes.
This should be the grunt of fixes necessary for the new workers, next
week should be quieter. We've got a pending series from Pavel on
cancelations, and how tasks and rings are indexed. Outside of that,
should just be minor fixes. Even with these fixes, we're still killing
a net ~80 lines"
* tag 'io_uring-5.12-2021-03-05' of git://git.kernel.dk/linux-block: (41 commits)
io_uring: don't restrict issue_flags for io_openat
io_uring: make SQPOLL thread parking saner
io-wq: kill hashed waitqueue before manager exits
io_uring: clear IOCB_WAITQ for non -EIOCBQUEUED return
io_uring: don't keep looping for more events if we can't flush overflow
io_uring: move to using create_io_thread()
kernel: provide create_io_thread() helper
io_uring: reliably cancel linked timeouts
io_uring: cancel-match based on flags
io-wq: ensure all pending work is canceled on exit
io_uring: ensure that threads freeze on suspend
io_uring: remove extra in_idle wake up
io_uring: inline __io_queue_async_work()
io_uring: inline io_req_clean_work()
io_uring: choose right tctx->io_wq for try cancel
io_uring: fix -EAGAIN retry with IOPOLL
io-wq: fix error path leak of buffered write hash map
io_uring: remove sqo_task
io_uring: kill sqo_dead and sqo submission halting
io_uring: ignore double poll add on the same waitqueue head
...
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45d189c606292 ("io_uring: replace force_nonblock with flags") did
something strange for io_openat() slicing all issue_flags but
IO_URING_F_NONBLOCK. Not a bug for now, but better to just forward the
flags.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We have this weird true/false return from parking, and then some of the
callers decide to look at that. It can lead to unbalanced parks and
sqd locking. Have the callers check the thread status once it's parked.
We know we have the lock at that point, so it's either valid or it's NULL.
Fix race with parking on thread exit. We need to be careful here with
ordering of the sdq->lock and the IO_SQ_THREAD_SHOULD_PARK bit.
Rename sqd->completion to sqd->parked to reflect that this is the only
thing this completion event doesn.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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If we race with shutting down the io-wq context and someone queueing
a hashed entry, then we can exit the manager with it armed. If it then
triggers after the manager has exited, we can have a use-after-free where
io_wqe_hash_wake() attempts to wake a now gone manager process.
Move the killing of the hashed write queue into the manager itself, so
that we know we've killed it before the task exits.
Fixes: e941894eae31 ("io-wq: make buffered file write hashed work map per-ctx")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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The callback can only be armed, if we get -EIOCBQUEUED returned. It's
important that we clear the WAITQ bit for other cases, otherwise we can
queue for async retry and filemap will assume that we're armed and
return -EAGAIN instead of just blocking for the IO.
Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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It doesn't make sense to wait for more events to come in, if we can't
even flush the overflow we already have to the ring. Return -EBUSY for
that condition, just like we do for attempts to submit with overflow
pending.
Cc: stable@vger.kernel.org # 5.11
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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This allows us to do task creation and setup without needing to use
completions to try and synchronize with the starting thread. Get rid of
the old io_wq_fork_thread() wrapper, and the 'wq' and 'worker' startup
completion events - we can now do setup before the task is running.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Linked timeouts are fired asynchronously (i.e. soft-irq), and use
generic cancellation paths to do its stuff, including poking into io-wq.
The problem is that it's racy to access tctx->io_wq, as
io_uring_task_cancel() and others may be happening at this exact moment.
Mark linked timeouts with REQ_F_INLIFGHT for now, making sure there are
no timeouts before io-wq destraction.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Instead of going into request internals, like checking req->file->f_op,
do match them based on REQ_F_INFLIGHT, it's set only when we want it to
be reliably cancelled.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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If we race on shutting down the io-wq, then we should ensure that any
work that was queued after workers shutdown is canceled. Harden the
add work check a bit too, checking for IO_WQ_BIT_EXIT and cancel if
it's set.
Add a WARN_ON() for having any work before we kill the io-wq context.
Reported-by: syzbot+91b4b56ead187d35c9d3@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Alex reports that his system fails to suspend using 5.12-rc1, with the
following dump:
[ 240.650300] PM: suspend entry (deep)
[ 240.650748] Filesystems sync: 0.000 seconds
[ 240.725605] Freezing user space processes ...
[ 260.739483] Freezing of tasks failed after 20.013 seconds (3 tasks refusing to freeze, wq_busy=0):
[ 260.739497] task:iou-mgr-446 state:S stack: 0 pid: 516 ppid: 439 flags:0x00004224
[ 260.739504] Call Trace:
[ 260.739507] ? sysvec_apic_timer_interrupt+0xb/0x81
[ 260.739515] ? pick_next_task_fair+0x197/0x1cde
[ 260.739519] ? sysvec_reschedule_ipi+0x2f/0x6a
[ 260.739522] ? asm_sysvec_reschedule_ipi+0x12/0x20
[ 260.739525] ? __schedule+0x57/0x6d6
[ 260.739529] ? del_timer_sync+0xb9/0x115
[ 260.739533] ? schedule+0x63/0xd5
[ 260.739536] ? schedule_timeout+0x219/0x356
[ 260.739540] ? __next_timer_interrupt+0xf1/0xf1
[ 260.739544] ? io_wq_manager+0x73/0xb1
[ 260.739549] ? io_wq_create+0x262/0x262
[ 260.739553] ? ret_from_fork+0x22/0x30
[ 260.739557] task:iou-mgr-517 state:S stack: 0 pid: 522 ppid: 439 flags:0x00004224
[ 260.739561] Call Trace:
[ 260.739563] ? sysvec_apic_timer_interrupt+0xb/0x81
[ 260.739566] ? pick_next_task_fair+0x16f/0x1cde
[ 260.739569] ? sysvec_apic_timer_interrupt+0xb/0x81
[ 260.739571] ? asm_sysvec_apic_timer_interrupt+0x12/0x20
[ 260.739574] ? __schedule+0x5b7/0x6d6
[ 260.739578] ? del_timer_sync+0x70/0x115
[ 260.739581] ? schedule_timeout+0x211/0x356
[ 260.739585] ? __next_timer_interrupt+0xf1/0xf1
[ 260.739588] ? io_wq_check_workers+0x15/0x11f
[ 260.739592] ? io_wq_manager+0x69/0xb1
[ 260.739596] ? io_wq_create+0x262/0x262
[ 260.739600] ? ret_from_fork+0x22/0x30
[ 260.739603] task:iou-wrk-517 state:S stack: 0 pid: 523 ppid: 439 flags:0x00004224
[ 260.739607] Call Trace:
[ 260.739609] ? __schedule+0x5b7/0x6d6
[ 260.739614] ? schedule+0x63/0xd5
[ 260.739617] ? schedule_timeout+0x219/0x356
[ 260.739621] ? __next_timer_interrupt+0xf1/0xf1
[ 260.739624] ? task_thread.isra.0+0x148/0x3af
[ 260.739628] ? task_thread_unbound+0xa/0xa
[ 260.739632] ? task_thread_bound+0x7/0x7
[ 260.739636] ? ret_from_fork+0x22/0x30
[ 260.739647] OOM killer enabled.
[ 260.739648] Restarting tasks ... done.
[ 260.740077] PM: suspend exit
Play nice and ensure that any thread we create will call try_to_freeze()
at an opportune time so that memory suspend can proceed. For the io-wq
worker threads, mark them as PF_NOFREEZE. They could potentially be
blocked for a long time.
Reported-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca>
Tested-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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io_dismantle_req() is always followed by io_put_task(), which already do
proper in_idle wake ups, so we can skip waking the owner task in
io_dismantle_req(). The rules are simpler now, do io_put_task() shortly
after ending a request, and it will be fine.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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__io_queue_async_work() is only called from io_queue_async_work(),
inline it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Inline io_req_clean_work(), less code and easier to analyse
tctx dependencies and refs usage.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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When we cancel SQPOLL, @task in io_uring_try_cancel_requests() will
differ from current. Use the right tctx from passed in @task, and don't
forget that it can be NULL when the io_uring ctx exits.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We no longer revert the iovec on -EIOCBQUEUED, see commit ab2125df921d,
and this started causing issues for IOPOLL on devies that run out of
request slots. Turns out what outside of needing a revert for those, we
also had a bug where we didn't properly setup retry inside the submission
path. That could cause re-import of the iovec, if any, and that could lead
to spurious results if the application had those allocated on the stack.
Catch -EAGAIN retry and make the iovec stable for IOPOLL, just like we do
for !IOPOLL retries.
Cc: <stable@vger.kernel.org> # 5.9+
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Reported-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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The 'err' path should include the hash put, we already grabbed a reference
once we get that far.
Fixes: e941894eae31 ("io-wq: make buffered file write hashed work map per-ctx")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Now, sqo_task is used only for a warning that is not interesting anymore
since sqo_dead is gone, remove all of that including ctx->sqo_task.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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As SQPOLL task doesn't poke into ->sqo_task anymore, there is no need to
kill the sqo when the master task exits. Before it was necessary to
avoid races accessing sqo_task->files with removing them.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: don't forget to enable SQPOLL before exit, if started disabled]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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syzbot reports a deadlock, attempting to lock the same spinlock twice:
============================================
WARNING: possible recursive locking detected
5.11.0-syzkaller #0 Not tainted
--------------------------------------------
swapper/1/0 is trying to acquire lock:
ffff88801b2b1130 (&runtime->sleep){..-.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline]
ffff88801b2b1130 (&runtime->sleep){..-.}-{2:2}, at: io_poll_double_wake+0x25f/0x6a0 fs/io_uring.c:4960
but task is already holding lock:
ffff88801b2b3130 (&runtime->sleep){..-.}-{2:2}, at: __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:137
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&runtime->sleep);
lock(&runtime->sleep);
*** DEADLOCK ***
May be due to missing lock nesting notation
2 locks held by swapper/1/0:
#0: ffff888147474908 (&group->lock){..-.}-{2:2}, at: _snd_pcm_stream_lock_irqsave+0x9f/0xd0 sound/core/pcm_native.c:170
#1: ffff88801b2b3130 (&runtime->sleep){..-.}-{2:2}, at: __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:137
stack backtrace:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.11.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0xfa/0x151 lib/dump_stack.c:120
print_deadlock_bug kernel/locking/lockdep.c:2829 [inline]
check_deadlock kernel/locking/lockdep.c:2872 [inline]
validate_chain kernel/locking/lockdep.c:3661 [inline]
__lock_acquire.cold+0x14c/0x3b4 kernel/locking/lockdep.c:4900
lock_acquire kernel/locking/lockdep.c:5510 [inline]
lock_acquire+0x1ab/0x730 kernel/locking/lockdep.c:5475
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:354 [inline]
io_poll_double_wake+0x25f/0x6a0 fs/io_uring.c:4960
__wake_up_common+0x147/0x650 kernel/sched/wait.c:108
__wake_up_common_lock+0xd0/0x130 kernel/sched/wait.c:138
snd_pcm_update_state+0x46a/0x540 sound/core/pcm_lib.c:203
snd_pcm_update_hw_ptr0+0xa75/0x1a50 sound/core/pcm_lib.c:464
snd_pcm_period_elapsed+0x160/0x250 sound/core/pcm_lib.c:1805
dummy_hrtimer_callback+0x94/0x1b0 sound/drivers/dummy.c:378
__run_hrtimer kernel/time/hrtimer.c:1519 [inline]
__hrtimer_run_queues+0x609/0xe40 kernel/time/hrtimer.c:1583
hrtimer_run_softirq+0x17b/0x360 kernel/time/hrtimer.c:1600
__do_softirq+0x29b/0x9f6 kernel/softirq.c:345
invoke_softirq kernel/softirq.c:221 [inline]
__irq_exit_rcu kernel/softirq.c:422 [inline]
irq_exit_rcu+0x134/0x200 kernel/softirq.c:434
sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1100
</IRQ>
asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:29 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:137 [inline]
RIP: 0010:acpi_safe_halt drivers/acpi/processor_idle.c:111 [inline]
RIP: 0010:acpi_idle_do_entry+0x1c9/0x250 drivers/acpi/processor_idle.c:516
Code: dd 38 6e f8 84 db 75 ac e8 54 32 6e f8 e8 0f 1c 74 f8 e9 0c 00 00 00 e8 45 32 6e f8 0f 00 2d 4e 4a c5 00 e8 39 32 6e f8 fb f4 <9c> 5b 81 e3 00 02 00 00 fa 31 ff 48 89 de e8 14 3a 6e f8 48 85 db
RSP: 0018:ffffc90000d47d18 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff8880115c3780 RSI: ffffffff89052537 RDI: 0000000000000000
RBP: ffff888141127064 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff81794168 R11: 0000000000000000 R12: 0000000000000001
R13: ffff888141127000 R14: ffff888141127064 R15: ffff888143331804
acpi_idle_enter+0x361/0x500 drivers/acpi/processor_idle.c:647
cpuidle_enter_state+0x1b1/0xc80 drivers/cpuidle/cpuidle.c:237
cpuidle_enter+0x4a/0xa0 drivers/cpuidle/cpuidle.c:351
call_cpuidle kernel/sched/idle.c:158 [inline]
cpuidle_idle_call kernel/sched/idle.c:239 [inline]
do_idle+0x3e1/0x590 kernel/sched/idle.c:300
cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:397
start_secondary+0x274/0x350 arch/x86/kernel/smpboot.c:272
secondary_startup_64_no_verify+0xb0/0xbb
which is due to the driver doing poll_wait() twice on the same
wait_queue_head. That is perfectly valid, but from checking the rest
of the kernel tree, it's the only driver that does this.
We can handle this just fine, we just need to ignore the second addition
as we'll get woken just fine on the first one.
Cc: stable@vger.kernel.org # 5.8+
Fixes: 18bceab101ad ("io_uring: allow POLL_ADD with double poll_wait() users")
Reported-by: syzbot+28abd693db9e92c160d8@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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If we create it in a disabled state because IORING_SETUP_R_DISABLED is
set on ring creation, we need to ensure that we've kicked the thread if
we're exiting before it's been explicitly disabled. Otherwise we can run
into a deadlock where exit is waiting go park the SQPOLL thread, but the
SQPOLL thread itself is waiting to get a signal to start.
That results in the below trace of both tasks hung, waiting on each other:
INFO: task syz-executor458:8401 blocked for more than 143 seconds.
Not tainted 5.11.0-next-20210226-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor458 state:D stack:27536 pid: 8401 ppid: 8400 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:4324 [inline]
__schedule+0x90c/0x21a0 kernel/sched/core.c:5075
schedule+0xcf/0x270 kernel/sched/core.c:5154
schedule_timeout+0x1db/0x250 kernel/time/timer.c:1868
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x168/0x270 kernel/sched/completion.c:138
io_sq_thread_park fs/io_uring.c:7115 [inline]
io_sq_thread_park+0xd5/0x130 fs/io_uring.c:7103
io_uring_cancel_task_requests+0x24c/0xd90 fs/io_uring.c:8745
__io_uring_files_cancel+0x110/0x230 fs/io_uring.c:8840
io_uring_files_cancel include/linux/io_uring.h:47 [inline]
do_exit+0x299/0x2a60 kernel/exit.c:780
do_group_exit+0x125/0x310 kernel/exit.c:922
__do_sys_exit_group kernel/exit.c:933 [inline]
__se_sys_exit_group kernel/exit.c:931 [inline]
__x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x43e899
RSP: 002b:00007ffe89376d48 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00000000004af2f0 RCX: 000000000043e899
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffffffffffc0 R09: 0000000010000000
R10: 0000000000008011 R11: 0000000000000246 R12: 00000000004af2f0
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
INFO: task iou-sqp-8401:8402 can't die for more than 143 seconds.
task:iou-sqp-8401 state:D stack:30272 pid: 8402 ppid: 8400 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:4324 [inline]
__schedule+0x90c/0x21a0 kernel/sched/core.c:5075
schedule+0xcf/0x270 kernel/sched/core.c:5154
schedule_timeout+0x1db/0x250 kernel/time/timer.c:1868
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x168/0x270 kernel/sched/completion.c:138
io_sq_thread+0x27d/0x1ae0 fs/io_uring.c:6717
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
INFO: task iou-sqp-8401:8402 blocked for more than 143 seconds.
Reported-by: syzbot+fb5458330b4442f2090d@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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io_run_ctx_fallback() can use xchg() instead of cmpxchg(). It's simpler
and faster.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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There is an unlikely but possible race using a freed context. That's
because req->task_work.func() can free a request, but we won't
necessarily find a completion in submit_state.comp and so all ctx refs
may be put by the time we do mutex_lock(&ctx->uring_ctx);
There are several reasons why it can miss going through
submit_state.comp: 1) req->task_work.func() didn't complete it itself,
but punted to iowq (e.g. reissue) and it got freed later, or a similar
situation with it overflowing and getting flushed by someone else, or
being submitted to IRQ completion, 2) As we don't hold the uring_lock,
someone else can do io_submit_flush_completions() and put our ref.
3) Bugs and code obscurities, e.g. failing to propagate issue_flags
properly.
One example is as follows
CPU1 | CPU2
=======================================================================
@req->task_work.func() |
-> @req overflwed, |
so submit_state.comp,nr==0 |
| flush overflows, and free @req
| ctx refs == 0, free it
ctx is dead, but we do |
lock + flush + unlock |
So take a ctx reference for each new ctx we see in __tctx_task_work(),
and do release it until we do all our flushing.
Fixes: 65453d1efbd2 ("io_uring: enable req cache for task_work items")
Reported-by: syzbot+a157ac7c03a56397f553@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: fold in my one-liner and fix ref mismatch]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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This was always a weird work-around or file referencing, and we don't
need it anymore. Get rid of it.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We already run the fallback task_work in io_uring_try_cancel_requests(),
no need to duplicate at ring exit explicitly.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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If we move it in there, then we no longer have to care about it in io-wq.
This means we can drop the cred handling in io-wq, and we can drop the
REQ_F_WORK_INITIALIZED flag and async init functions as that was the last
user of it since we moved to the new workers. Then we can also drop
io_wq_work->creds, and just hold the personality u16 in there instead.
Suggested-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We're no longer checking anything that requires the work item to be
initialized, as we're not carrying any file related state there.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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