linux.git/drivers/block/rnbd, branch v5.12.5 Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git block/rnbd-clt: Check the return value of the function rtrs_clt_query 2021-05-19T08:56:29+00:00 Md Haris Iqbal haris.iqbal@cloud.ionos.com 2021-04-28T06:13:58+00:00 b345ba612d4d33d11d1a3dfa901263a56d51ee1e [ Upstream commit 1056ad829ec43f9b705b507c2093b05e2088b0b7 ] In case none of the paths are in connected state, the function rtrs_clt_query returns an error. In such a case, error out since the values in the rtrs_attrs structure would be garbage. Fixes: f7a7a5c228d45 ("block/rnbd: client: main functionality") Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com> Reviewed-by: Guoqing Jiang <guoqing.jiang@ionos.com> Signed-off-by: Jack Wang <jinpu.wang@ionos.com> Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com> Link: https://lore.kernel.org/r/20210428061359.206794-4-gi-oh.kim@ionos.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 1056ad829ec43f9b705b507c2093b05e2088b0b7 ]

In case none of the paths are in connected state, the function
rtrs_clt_query returns an error. In such a case, error out since the
values in the rtrs_attrs structure would be garbage.

Fixes: f7a7a5c228d45 ("block/rnbd: client: main functionality")
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Reviewed-by: Guoqing Jiang <guoqing.jiang@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Link: https://lore.kernel.org/r/20210428061359.206794-4-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
block/rnbd-clt: Change queue_depth type in rnbd_clt_session to size_t 2021-05-19T08:56:28+00:00 Md Haris Iqbal haris.iqbal@cloud.ionos.com 2021-04-28T06:13:56+00:00 05a023f98e0d8913da07e37a6501ad754a2251b7 [ Upstream commit 80d43cbd46155744ee450d2476ee4fcf2917ae9b ] The member queue_depth in the structure rnbd_clt_session is read from the rtrs client side using the function rtrs_clt_query, which in turn is read from the rtrs_clt structure. It should really be of type size_t. Fixes: 90426e89f54db ("block/rnbd: client: private header with client structs and functions") Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com> Reviewed-by: Guoqing Jiang <guoqing.jiang@ionos.com> Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com> Link: https://lore.kernel.org/r/20210428061359.206794-2-gi-oh.kim@ionos.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 80d43cbd46155744ee450d2476ee4fcf2917ae9b ]

The member queue_depth in the structure rnbd_clt_session is read from the
rtrs client side using the function rtrs_clt_query, which in turn is read
from the rtrs_clt structure. It should really be of type size_t.

Fixes: 90426e89f54db ("block/rnbd: client: private header with client structs and functions")
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Reviewed-by: Guoqing Jiang <guoqing.jiang@ionos.com>
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Link: https://lore.kernel.org/r/20210428061359.206794-2-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
block/rnbd-clt-sysfs: Remove copy buffer overlap in rnbd_clt_get_path_name 2021-05-14T08:52:42+00:00 Dima Stepanov dmitrii.stepanov@cloud.ionos.com 2021-04-19T07:37:21+00:00 9b7d064beb344b538c0073a17de7aa0ce87388f6 [ Upstream commit 3db7cf55d532a15ea26b4a14e8f8729ccd96fd22 ] cppcheck report the following error: rnbd/rnbd-clt-sysfs.c:522:36: error: The variable 'buf' is used both as a parameter and as destination in snprintf(). The origin and destination buffers overlap. Quote from glibc (C-library) documentation (http://www.gnu.org/software/libc/manual/html_mono/libc.html#Formatted-Output-Functions): "If copying takes place between objects that overlap as a result of a call to sprintf() or snprintf(), the results are undefined." [sprintfOverlappingData] Fix it by initializing the buf variable in the first snprintf call. Fixes: 91f4acb2801c ("block/rnbd-clt: support mapping two devices") Signed-off-by: Dima Stepanov <dmitrii.stepanov@ionos.com> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jack Wang <jinpu.wang@ionos.com> Signed-off-by: Gioh Kim <gi-oh.kim@cloud.ionos.com> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Link: https://lore.kernel.org/r/20210419073722.15351-19-gi-oh.kim@ionos.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 3db7cf55d532a15ea26b4a14e8f8729ccd96fd22 ]

cppcheck report the following error:
  rnbd/rnbd-clt-sysfs.c:522:36: error: The variable 'buf' is used both
  as a parameter and as destination in snprintf(). The origin and
  destination buffers overlap. Quote from glibc (C-library)
  documentation
  (http://www.gnu.org/software/libc/manual/html_mono/libc.html#Formatted-Output-Functions):
  "If copying takes place between objects that overlap as a result of a
  call to sprintf() or snprintf(), the results are undefined."
  [sprintfOverlappingData]
Fix it by initializing the buf variable in the first snprintf call.

Fixes: 91f4acb2801c ("block/rnbd-clt: support mapping two devices")
Signed-off-by: Dima Stepanov <dmitrii.stepanov@ionos.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Gioh Kim <gi-oh.kim@cloud.ionos.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210419073722.15351-19-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
block/rnbd-clt: Fix missing a memory free when unloading the module 2021-05-12T06:39:53+00:00 Gioh Kim gi-oh.kim@cloud.ionos.com 2021-04-19T07:37:15+00:00 87a6d381613a31648781955160d69140f41b716d [ Upstream commit 12b06533104e802df73c1fbe159437c19933d6c0 ] When unloading the rnbd-clt module, it does not free a memory including the filename of the symbolic link to /sys/block/rnbdX. It is found by kmemleak as below. unreferenced object 0xffff9f1a83d3c740 (size 16): comm "bash", pid 736, jiffies 4295179665 (age 9841.310s) hex dump (first 16 bytes): 21 64 65 76 21 6e 75 6c 6c 62 30 40 62 6c 61 00 !dev!nullb0@bla. backtrace: [<0000000039f0c55e>] 0xffffffffc0456c24 [<000000001aab9513>] kernfs_fop_write+0xcf/0x1c0 [<00000000db5aa4b3>] vfs_write+0xdb/0x1d0 [<000000007a2e2207>] ksys_write+0x65/0xe0 [<00000000055e280a>] do_syscall_64+0x50/0x1b0 [<00000000c2b51831>] entry_SYSCALL_64_after_hwframe+0x49/0xbe Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com> Signed-off-by: Jack Wang <jinpu.wang@ionos.com> Link: https://lore.kernel.org/r/20210419073722.15351-13-gi-oh.kim@ionos.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 12b06533104e802df73c1fbe159437c19933d6c0 ]

When unloading the rnbd-clt module, it does not free a memory
including the filename of the symbolic link to /sys/block/rnbdX.

It is found by kmemleak as below.

unreferenced object 0xffff9f1a83d3c740 (size 16):
  comm "bash", pid 736, jiffies 4295179665 (age 9841.310s)
  hex dump (first 16 bytes):
    21 64 65 76 21 6e 75 6c 6c 62 30 40 62 6c 61 00  !dev!nullb0@bla.
  backtrace:
    [<0000000039f0c55e>] 0xffffffffc0456c24
    [<000000001aab9513>] kernfs_fop_write+0xcf/0x1c0
    [<00000000db5aa4b3>] vfs_write+0xdb/0x1d0
    [<000000007a2e2207>] ksys_write+0x65/0xe0
    [<00000000055e280a>] do_syscall_64+0x50/0x1b0
    [<00000000c2b51831>] entry_SYSCALL_64_after_hwframe+0x49/0xbe

Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Link: https://lore.kernel.org/r/20210419073722.15351-13-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
block/rnbd-srv: Prevent a deadlock generated by accessing sysfs in parallel 2021-05-12T06:39:53+00:00 Gioh Kim gi-oh.kim@cloud.ionos.com 2021-04-19T07:37:12+00:00 fba4bf102cf8f0ebc46d0232d59605cc0cc40a9e [ Upstream commit b168e1d85cf3201663698dd9dcb3d46c7e67f621 ] We got a warning message below. When server tries to close one session by force, it locks the sysfs interface and locks the srv_sess lock. The problem is that client can send a request to close at the same time. By close request, server locks the srv_sess lock and locks the sysfs to remove the sysfs interfaces. The simplest way to prevent that situation could be just use mutex_trylock. [ 234.153965] ====================================================== [ 234.154093] WARNING: possible circular locking dependency detected [ 234.154219] 5.4.84-storage #5.4.84-1+feature+linux+5.4.y+dbg+20201216.1319+b6b887b~deb10 Tainted: G O [ 234.154381] ------------------------------------------------------ [ 234.154531] kworker/1:1H/618 is trying to acquire lock: [ 234.154651] ffff8887a09db0a8 (kn->count#132){++++}, at: kernfs_remove_by_name_ns+0x40/0x80 [ 234.154819] but task is already holding lock: [ 234.154965] ffff8887ae5f6518 (&srv_sess->lock){+.+.}, at: rnbd_srv_rdma_ev+0x144/0x1590 [rnbd_server] [ 234.155132] which lock already depends on the new lock. [ 234.155311] the existing dependency chain (in reverse order) is: [ 234.155462] -> #1 (&srv_sess->lock){+.+.}: [ 234.155614] __mutex_lock+0x134/0xcb0 [ 234.155761] rnbd_srv_sess_dev_force_close+0x36/0x50 [rnbd_server] [ 234.155889] rnbd_srv_dev_session_force_close_store+0x69/0xc0 [rnbd_server] [ 234.156042] kernfs_fop_write+0x13f/0x240 [ 234.156162] vfs_write+0xf3/0x280 [ 234.156278] ksys_write+0xba/0x150 [ 234.156395] do_syscall_64+0x62/0x270 [ 234.156513] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 234.156632] -> #0 (kn->count#132){++++}: [ 234.156782] __lock_acquire+0x129e/0x23a0 [ 234.156900] lock_acquire+0xf3/0x210 [ 234.157043] __kernfs_remove+0x42b/0x4c0 [ 234.157161] kernfs_remove_by_name_ns+0x40/0x80 [ 234.157282] remove_files+0x3f/0xa0 [ 234.157399] sysfs_remove_group+0x4a/0xb0 [ 234.157519] rnbd_srv_destroy_dev_session_sysfs+0x19/0x30 [rnbd_server] [ 234.157648] rnbd_srv_rdma_ev+0x14c/0x1590 [rnbd_server] [ 234.157775] process_io_req+0x29a/0x6a0 [rtrs_server] [ 234.157924] __ib_process_cq+0x8c/0x100 [ib_core] [ 234.158709] ib_cq_poll_work+0x31/0xb0 [ib_core] [ 234.158834] process_one_work+0x4e5/0xaa0 [ 234.158958] worker_thread+0x65/0x5c0 [ 234.159078] kthread+0x1e0/0x200 [ 234.159194] ret_from_fork+0x24/0x30 [ 234.159309] other info that might help us debug this: [ 234.159513] Possible unsafe locking scenario: [ 234.159658] CPU0 CPU1 [ 234.159775] ---- ---- [ 234.159891] lock(&srv_sess->lock); [ 234.160005] lock(kn->count#132); [ 234.160128] lock(&srv_sess->lock); [ 234.160250] lock(kn->count#132); [ 234.160364] *** DEADLOCK *** [ 234.160536] 3 locks held by kworker/1:1H/618: [ 234.160677] #0: ffff8883ca1ed528 ((wq_completion)ib-comp-wq){+.+.}, at: process_one_work+0x40a/0xaa0 [ 234.160840] #1: ffff8883d2d5fe10 ((work_completion)(&cq->work)){+.+.}, at: process_one_work+0x40a/0xaa0 [ 234.161003] #2: ffff8887ae5f6518 (&srv_sess->lock){+.+.}, at: rnbd_srv_rdma_ev+0x144/0x1590 [rnbd_server] [ 234.161168] stack backtrace: [ 234.161312] CPU: 1 PID: 618 Comm: kworker/1:1H Tainted: G O 5.4.84-storage #5.4.84-1+feature+linux+5.4.y+dbg+20201216.1319+b6b887b~deb10 [ 234.161490] Hardware name: Supermicro H8QG6/H8QG6, BIOS 3.00 09/04/2012 [ 234.161643] Workqueue: ib-comp-wq ib_cq_poll_work [ib_core] [ 234.161765] Call Trace: [ 234.161910] dump_stack+0x96/0xe0 [ 234.162028] check_noncircular+0x29e/0x2e0 [ 234.162148] ? print_circular_bug+0x100/0x100 [ 234.162267] ? register_lock_class+0x1ad/0x8a0 [ 234.162385] ? __lock_acquire+0x68e/0x23a0 [ 234.162505] ? trace_event_raw_event_lock+0x190/0x190 [ 234.162626] __lock_acquire+0x129e/0x23a0 [ 234.162746] ? register_lock_class+0x8a0/0x8a0 [ 234.162866] lock_acquire+0xf3/0x210 [ 234.162982] ? kernfs_remove_by_name_ns+0x40/0x80 [ 234.163127] __kernfs_remove+0x42b/0x4c0 [ 234.163243] ? kernfs_remove_by_name_ns+0x40/0x80 [ 234.163363] ? kernfs_fop_readdir+0x3b0/0x3b0 [ 234.163482] ? strlen+0x1f/0x40 [ 234.163596] ? strcmp+0x30/0x50 [ 234.163712] kernfs_remove_by_name_ns+0x40/0x80 [ 234.163832] remove_files+0x3f/0xa0 [ 234.163948] sysfs_remove_group+0x4a/0xb0 [ 234.164068] rnbd_srv_destroy_dev_session_sysfs+0x19/0x30 [rnbd_server] [ 234.164196] rnbd_srv_rdma_ev+0x14c/0x1590 [rnbd_server] [ 234.164345] ? _raw_spin_unlock_irqrestore+0x43/0x50 [ 234.164466] ? lockdep_hardirqs_on+0x1a8/0x290 [ 234.164597] ? mlx4_ib_poll_cq+0x927/0x1280 [mlx4_ib] [ 234.164732] ? rnbd_get_sess_dev+0x270/0x270 [rnbd_server] [ 234.164859] process_io_req+0x29a/0x6a0 [rtrs_server] [ 234.164982] ? rnbd_get_sess_dev+0x270/0x270 [rnbd_server] [ 234.165130] __ib_process_cq+0x8c/0x100 [ib_core] [ 234.165279] ib_cq_poll_work+0x31/0xb0 [ib_core] [ 234.165404] process_one_work+0x4e5/0xaa0 [ 234.165550] ? pwq_dec_nr_in_flight+0x160/0x160 [ 234.165675] ? do_raw_spin_lock+0x119/0x1d0 [ 234.165796] worker_thread+0x65/0x5c0 [ 234.165914] ? process_one_work+0xaa0/0xaa0 [ 234.166031] kthread+0x1e0/0x200 [ 234.166147] ? kthread_create_worker_on_cpu+0xc0/0xc0 [ 234.166268] ret_from_fork+0x24/0x30 [ 234.251591] rnbd_server L243: </dev/loop1@close_device_session>: Device closed [ 234.604221] rnbd_server L264: RTRS Session close_device_session disconnected Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com> Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com> Signed-off-by: Jack Wang <jinpu.wang@ionos.com> Link: https://lore.kernel.org/r/20210419073722.15351-10-gi-oh.kim@ionos.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit b168e1d85cf3201663698dd9dcb3d46c7e67f621 ]

We got a warning message below.
When server tries to close one session by force, it locks the sysfs
interface and locks the srv_sess lock.
The problem is that client can send a request to close at the same time.
By close request, server locks the srv_sess lock and locks the sysfs
to remove the sysfs interfaces.

The simplest way to prevent that situation could be just use
mutex_trylock.

[  234.153965] ======================================================
[  234.154093] WARNING: possible circular locking dependency detected
[  234.154219] 5.4.84-storage #5.4.84-1+feature+linux+5.4.y+dbg+20201216.1319+b6b887b~deb10 Tainted: G           O
[  234.154381] ------------------------------------------------------
[  234.154531] kworker/1:1H/618 is trying to acquire lock:
[  234.154651] ffff8887a09db0a8 (kn->count#132){++++}, at: kernfs_remove_by_name_ns+0x40/0x80
[  234.154819]
               but task is already holding lock:
[  234.154965] ffff8887ae5f6518 (&srv_sess->lock){+.+.}, at: rnbd_srv_rdma_ev+0x144/0x1590 [rnbd_server]
[  234.155132]
               which lock already depends on the new lock.

[  234.155311]
               the existing dependency chain (in reverse order) is:
[  234.155462]
               -> #1 (&srv_sess->lock){+.+.}:
[  234.155614]        __mutex_lock+0x134/0xcb0
[  234.155761]        rnbd_srv_sess_dev_force_close+0x36/0x50 [rnbd_server]
[  234.155889]        rnbd_srv_dev_session_force_close_store+0x69/0xc0 [rnbd_server]
[  234.156042]        kernfs_fop_write+0x13f/0x240
[  234.156162]        vfs_write+0xf3/0x280
[  234.156278]        ksys_write+0xba/0x150
[  234.156395]        do_syscall_64+0x62/0x270
[  234.156513]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  234.156632]
               -> #0 (kn->count#132){++++}:
[  234.156782]        __lock_acquire+0x129e/0x23a0
[  234.156900]        lock_acquire+0xf3/0x210
[  234.157043]        __kernfs_remove+0x42b/0x4c0
[  234.157161]        kernfs_remove_by_name_ns+0x40/0x80
[  234.157282]        remove_files+0x3f/0xa0
[  234.157399]        sysfs_remove_group+0x4a/0xb0
[  234.157519]        rnbd_srv_destroy_dev_session_sysfs+0x19/0x30 [rnbd_server]
[  234.157648]        rnbd_srv_rdma_ev+0x14c/0x1590 [rnbd_server]
[  234.157775]        process_io_req+0x29a/0x6a0 [rtrs_server]
[  234.157924]        __ib_process_cq+0x8c/0x100 [ib_core]
[  234.158709]        ib_cq_poll_work+0x31/0xb0 [ib_core]
[  234.158834]        process_one_work+0x4e5/0xaa0
[  234.158958]        worker_thread+0x65/0x5c0
[  234.159078]        kthread+0x1e0/0x200
[  234.159194]        ret_from_fork+0x24/0x30
[  234.159309]
               other info that might help us debug this:

[  234.159513]  Possible unsafe locking scenario:

[  234.159658]        CPU0                    CPU1
[  234.159775]        ----                    ----
[  234.159891]   lock(&srv_sess->lock);
[  234.160005]                                lock(kn->count#132);
[  234.160128]                                lock(&srv_sess->lock);
[  234.160250]   lock(kn->count#132);
[  234.160364]
                *** DEADLOCK ***

[  234.160536] 3 locks held by kworker/1:1H/618:
[  234.160677]  #0: ffff8883ca1ed528 ((wq_completion)ib-comp-wq){+.+.}, at: process_one_work+0x40a/0xaa0
[  234.160840]  #1: ffff8883d2d5fe10 ((work_completion)(&cq->work)){+.+.}, at: process_one_work+0x40a/0xaa0
[  234.161003]  #2: ffff8887ae5f6518 (&srv_sess->lock){+.+.}, at: rnbd_srv_rdma_ev+0x144/0x1590 [rnbd_server]
[  234.161168]
               stack backtrace:
[  234.161312] CPU: 1 PID: 618 Comm: kworker/1:1H Tainted: G           O      5.4.84-storage #5.4.84-1+feature+linux+5.4.y+dbg+20201216.1319+b6b887b~deb10
[  234.161490] Hardware name: Supermicro H8QG6/H8QG6, BIOS 3.00       09/04/2012
[  234.161643] Workqueue: ib-comp-wq ib_cq_poll_work [ib_core]
[  234.161765] Call Trace:
[  234.161910]  dump_stack+0x96/0xe0
[  234.162028]  check_noncircular+0x29e/0x2e0
[  234.162148]  ? print_circular_bug+0x100/0x100
[  234.162267]  ? register_lock_class+0x1ad/0x8a0
[  234.162385]  ? __lock_acquire+0x68e/0x23a0
[  234.162505]  ? trace_event_raw_event_lock+0x190/0x190
[  234.162626]  __lock_acquire+0x129e/0x23a0
[  234.162746]  ? register_lock_class+0x8a0/0x8a0
[  234.162866]  lock_acquire+0xf3/0x210
[  234.162982]  ? kernfs_remove_by_name_ns+0x40/0x80
[  234.163127]  __kernfs_remove+0x42b/0x4c0
[  234.163243]  ? kernfs_remove_by_name_ns+0x40/0x80
[  234.163363]  ? kernfs_fop_readdir+0x3b0/0x3b0
[  234.163482]  ? strlen+0x1f/0x40
[  234.163596]  ? strcmp+0x30/0x50
[  234.163712]  kernfs_remove_by_name_ns+0x40/0x80
[  234.163832]  remove_files+0x3f/0xa0
[  234.163948]  sysfs_remove_group+0x4a/0xb0
[  234.164068]  rnbd_srv_destroy_dev_session_sysfs+0x19/0x30 [rnbd_server]
[  234.164196]  rnbd_srv_rdma_ev+0x14c/0x1590 [rnbd_server]
[  234.164345]  ? _raw_spin_unlock_irqrestore+0x43/0x50
[  234.164466]  ? lockdep_hardirqs_on+0x1a8/0x290
[  234.164597]  ? mlx4_ib_poll_cq+0x927/0x1280 [mlx4_ib]
[  234.164732]  ? rnbd_get_sess_dev+0x270/0x270 [rnbd_server]
[  234.164859]  process_io_req+0x29a/0x6a0 [rtrs_server]
[  234.164982]  ? rnbd_get_sess_dev+0x270/0x270 [rnbd_server]
[  234.165130]  __ib_process_cq+0x8c/0x100 [ib_core]
[  234.165279]  ib_cq_poll_work+0x31/0xb0 [ib_core]
[  234.165404]  process_one_work+0x4e5/0xaa0
[  234.165550]  ? pwq_dec_nr_in_flight+0x160/0x160
[  234.165675]  ? do_raw_spin_lock+0x119/0x1d0
[  234.165796]  worker_thread+0x65/0x5c0
[  234.165914]  ? process_one_work+0xaa0/0xaa0
[  234.166031]  kthread+0x1e0/0x200
[  234.166147]  ? kthread_create_worker_on_cpu+0xc0/0xc0
[  234.166268]  ret_from_fork+0x24/0x30
[  234.251591] rnbd_server L243: </dev/loop1@close_device_session>: Device closed
[  234.604221] rnbd_server L264: RTRS Session close_device_session disconnected

Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Link: https://lore.kernel.org/r/20210419073722.15351-10-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
block/rnbd-clt: avoid module unload race with close confirmation 2021-01-08T15:19:18+00:00 Jack Wang jinpu.wang@cloud.ionos.com 2021-01-08T14:36:34+00:00 3a21777c6ee99749bac10727b3c17e5bcfebe5c1 We had kernel panic, it is caused by unload module and last close confirmation. call trace: [1196029.743127] free_sess+0x15/0x50 [rtrs_client] [1196029.743128] rtrs_clt_close+0x4c/0x70 [rtrs_client] [1196029.743129] ? rnbd_clt_unmap_device+0x1b0/0x1b0 [rnbd_client] [1196029.743130] close_rtrs+0x25/0x50 [rnbd_client] [1196029.743131] rnbd_client_exit+0x93/0xb99 [rnbd_client] [1196029.743132] __x64_sys_delete_module+0x190/0x260 And in the crashdump confirmation kworker is also running. PID: 6943 TASK: ffff9e2ac8098000 CPU: 4 COMMAND: "kworker/4:2" #0 [ffffb206cf337c30] __schedule at ffffffff9f93f891 #1 [ffffb206cf337cc8] schedule at ffffffff9f93fe98 #2 [ffffb206cf337cd0] schedule_timeout at ffffffff9f943938 #3 [ffffb206cf337d50] wait_for_completion at ffffffff9f9410a7 #4 [ffffb206cf337da0] __flush_work at ffffffff9f08ce0e #5 [ffffb206cf337e20] rtrs_clt_close_conns at ffffffffc0d5f668 [rtrs_client] #6 [ffffb206cf337e48] rtrs_clt_close at ffffffffc0d5f801 [rtrs_client] #7 [ffffb206cf337e68] close_rtrs at ffffffffc0d26255 [rnbd_client] #8 [ffffb206cf337e78] free_sess at ffffffffc0d262ad [rnbd_client] #9 [ffffb206cf337e88] rnbd_clt_put_dev at ffffffffc0d266a7 [rnbd_client] The problem is both code path try to close same session, which lead to panic. To fix it, just skip the sess if the refcount already drop to 0. Fixes: f7a7a5c228d4 ("block/rnbd: client: main functionality") Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com> Reviewed-by: Gioh Kim <gi-oh.kim@cloud.ionos.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
We had kernel panic, it is caused by unload module and last
close confirmation.

call trace:
[1196029.743127]  free_sess+0x15/0x50 [rtrs_client]
[1196029.743128]  rtrs_clt_close+0x4c/0x70 [rtrs_client]
[1196029.743129]  ? rnbd_clt_unmap_device+0x1b0/0x1b0 [rnbd_client]
[1196029.743130]  close_rtrs+0x25/0x50 [rnbd_client]
[1196029.743131]  rnbd_client_exit+0x93/0xb99 [rnbd_client]
[1196029.743132]  __x64_sys_delete_module+0x190/0x260

And in the crashdump confirmation kworker is also running.
PID: 6943   TASK: ffff9e2ac8098000  CPU: 4   COMMAND: "kworker/4:2"
 #0 [ffffb206cf337c30] __schedule at ffffffff9f93f891
 #1 [ffffb206cf337cc8] schedule at ffffffff9f93fe98
 #2 [ffffb206cf337cd0] schedule_timeout at ffffffff9f943938
 #3 [ffffb206cf337d50] wait_for_completion at ffffffff9f9410a7
 #4 [ffffb206cf337da0] __flush_work at ffffffff9f08ce0e
 #5 [ffffb206cf337e20] rtrs_clt_close_conns at ffffffffc0d5f668 [rtrs_client]
 #6 [ffffb206cf337e48] rtrs_clt_close at ffffffffc0d5f801 [rtrs_client]
 #7 [ffffb206cf337e68] close_rtrs at ffffffffc0d26255 [rnbd_client]
 #8 [ffffb206cf337e78] free_sess at ffffffffc0d262ad [rnbd_client]
 #9 [ffffb206cf337e88] rnbd_clt_put_dev at ffffffffc0d266a7 [rnbd_client]

The problem is both code path try to close same session, which lead to
panic.

To fix it, just skip the sess if the refcount already drop to 0.

Fixes: f7a7a5c228d4 ("block/rnbd: client: main functionality")
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Reviewed-by: Gioh Kim <gi-oh.kim@cloud.ionos.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block/rnbd: Adding name to the Contributors List 2021-01-08T15:19:18+00:00 Swapnil Ingle ingleswapnil@gmail.com 2021-01-08T14:36:33+00:00 ef8048dd2345d070c41bc7df16763fd4d8fac296 Adding name to the Contributors List Signed-off-by: Swapnil Ingle <ingleswapnil@gmail.com> Acked-by: Jack Wang <jinpu.wang@cloud.ionos.com> Acked-by: Danil Kipnis <danil.kipnis@cloud.ionos.com> Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
Adding name to the Contributors List

Signed-off-by: Swapnil Ingle <ingleswapnil@gmail.com>
Acked-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Acked-by: Danil Kipnis <danil.kipnis@cloud.ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block/rnbd-clt: Fix sg table use after free 2021-01-08T15:19:18+00:00 Guoqing Jiang guoqing.jiang@cloud.ionos.com 2021-01-08T14:36:32+00:00 80f99093d81370c5cec37fca3b5a6bdf6bddf0f6 Since dynamically allocate sglist is used for rnbd_iu, we can't free sg table after send_usr_msg since the callback function (cqe.done) could still access the sglist. Otherwise KASAN reports UAF issue: [ 4856.600257] BUG: KASAN: use-after-free in dma_direct_unmap_sg+0x53/0x290 [ 4856.600772] Read of size 4 at addr ffff888206af3a98 by task swapper/1/0 [ 4856.601729] CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: G W 5.10.0-pserver #5.10.0-1+feature+linux+next+20201214.1025+0910d71 [ 4856.601748] Hardware name: Supermicro Super Server/X11DDW-L, BIOS 3.3 02/21/2020 [ 4856.601766] Call Trace: [ 4856.601785] <IRQ> [ 4856.601822] dump_stack+0x99/0xcb [ 4856.601856] ? dma_direct_unmap_sg+0x53/0x290 [ 4856.601888] print_address_description.constprop.7+0x1e/0x230 [ 4856.601913] ? freeze_kernel_threads+0x73/0x73 [ 4856.601965] ? mark_held_locks+0x29/0xa0 [ 4856.602019] ? dma_direct_unmap_sg+0x53/0x290 [ 4856.602039] ? dma_direct_unmap_sg+0x53/0x290 [ 4856.602079] kasan_report.cold.9+0x37/0x7c [ 4856.602188] ? mlx5_ib_post_recv+0x430/0x520 [mlx5_ib] [ 4856.602209] ? dma_direct_unmap_sg+0x53/0x290 [ 4856.602256] dma_direct_unmap_sg+0x53/0x290 [ 4856.602366] complete_rdma_req+0x188/0x4b0 [rtrs_client] [ 4856.602451] ? rtrs_clt_close+0x80/0x80 [rtrs_client] [ 4856.602535] ? mlx5_ib_poll_cq+0x48b/0x16e0 [mlx5_ib] [ 4856.602589] ? radix_tree_insert+0x3a0/0x3a0 [ 4856.602610] ? do_raw_spin_lock+0x119/0x1d0 [ 4856.602647] ? rwlock_bug.part.1+0x60/0x60 [ 4856.602740] rtrs_clt_rdma_done+0x3f7/0x670 [rtrs_client] [ 4856.602804] ? rtrs_clt_rdma_cm_handler+0xda0/0xda0 [rtrs_client] [ 4856.602857] ? check_flags.part.31+0x6c/0x1f0 [ 4856.602927] ? rcu_read_lock_sched_held+0xaf/0xe0 [ 4856.602963] ? rcu_read_lock_bh_held+0xc0/0xc0 [ 4856.603137] __ib_process_cq+0x10a/0x350 [ib_core] [ 4856.603309] ib_poll_handler+0x41/0x1c0 [ib_core] [ 4856.603358] irq_poll_softirq+0xe6/0x280 [ 4856.603392] ? lockdep_hardirqs_on_prepare+0x111/0x210 [ 4856.603446] __do_softirq+0x10d/0x646 [ 4856.603540] asm_call_irq_on_stack+0x12/0x20 [ 4856.603563] </IRQ> [ 4856.605096] Allocated by task 8914: [ 4856.605510] kasan_save_stack+0x19/0x40 [ 4856.605532] __kasan_kmalloc.constprop.7+0xc1/0xd0 [ 4856.605552] __kmalloc+0x155/0x320 [ 4856.605574] __sg_alloc_table+0x155/0x1c0 [ 4856.605594] sg_alloc_table+0x1f/0x50 [ 4856.605620] send_msg_sess_info+0x119/0x2e0 [rnbd_client] [ 4856.605646] remap_devs+0x71/0x210 [rnbd_client] [ 4856.605676] init_sess+0xad8/0xe10 [rtrs_client] [ 4856.605706] rtrs_clt_reconnect_work+0xd6/0x170 [rtrs_client] [ 4856.605728] process_one_work+0x521/0xa90 [ 4856.605748] worker_thread+0x65/0x5b0 [ 4856.605769] kthread+0x1f2/0x210 [ 4856.605789] ret_from_fork+0x22/0x30 [ 4856.606159] Freed by task 8914: [ 4856.606559] kasan_save_stack+0x19/0x40 [ 4856.606580] kasan_set_track+0x1c/0x30 [ 4856.606601] kasan_set_free_info+0x1b/0x30 [ 4856.606622] __kasan_slab_free+0x108/0x150 [ 4856.606642] slab_free_freelist_hook+0x64/0x190 [ 4856.606661] kfree+0xe2/0x650 [ 4856.606681] __sg_free_table+0xa4/0x100 [ 4856.606707] send_msg_sess_info+0x1d6/0x2e0 [rnbd_client] [ 4856.606733] remap_devs+0x71/0x210 [rnbd_client] [ 4856.606763] init_sess+0xad8/0xe10 [rtrs_client] [ 4856.606792] rtrs_clt_reconnect_work+0xd6/0x170 [rtrs_client] [ 4856.606813] process_one_work+0x521/0xa90 [ 4856.606833] worker_thread+0x65/0x5b0 [ 4856.606853] kthread+0x1f2/0x210 [ 4856.606872] ret_from_fork+0x22/0x30 The solution is to free iu's sgtable after the iu is not used anymore. And also move sg_alloc_table into rnbd_get_iu accordingly. Fixes: 5a1328d0c3a7 ("block/rnbd-clt: Dynamically allocate sglist for rnbd_iu") Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com> Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
Since dynamically allocate sglist is used for rnbd_iu, we can't free sg
table after send_usr_msg since the callback function (cqe.done) could
still access the sglist.

Otherwise KASAN reports UAF issue:

[ 4856.600257] BUG: KASAN: use-after-free in dma_direct_unmap_sg+0x53/0x290
[ 4856.600772] Read of size 4 at addr ffff888206af3a98 by task swapper/1/0

[ 4856.601729] CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: G        W         5.10.0-pserver #5.10.0-1+feature+linux+next+20201214.1025+0910d71
[ 4856.601748] Hardware name: Supermicro Super Server/X11DDW-L, BIOS 3.3 02/21/2020
[ 4856.601766] Call Trace:
[ 4856.601785]  <IRQ>
[ 4856.601822]  dump_stack+0x99/0xcb
[ 4856.601856]  ? dma_direct_unmap_sg+0x53/0x290
[ 4856.601888]  print_address_description.constprop.7+0x1e/0x230
[ 4856.601913]  ? freeze_kernel_threads+0x73/0x73
[ 4856.601965]  ? mark_held_locks+0x29/0xa0
[ 4856.602019]  ? dma_direct_unmap_sg+0x53/0x290
[ 4856.602039]  ? dma_direct_unmap_sg+0x53/0x290
[ 4856.602079]  kasan_report.cold.9+0x37/0x7c
[ 4856.602188]  ? mlx5_ib_post_recv+0x430/0x520 [mlx5_ib]
[ 4856.602209]  ? dma_direct_unmap_sg+0x53/0x290
[ 4856.602256]  dma_direct_unmap_sg+0x53/0x290
[ 4856.602366]  complete_rdma_req+0x188/0x4b0 [rtrs_client]
[ 4856.602451]  ? rtrs_clt_close+0x80/0x80 [rtrs_client]
[ 4856.602535]  ? mlx5_ib_poll_cq+0x48b/0x16e0 [mlx5_ib]
[ 4856.602589]  ? radix_tree_insert+0x3a0/0x3a0
[ 4856.602610]  ? do_raw_spin_lock+0x119/0x1d0
[ 4856.602647]  ? rwlock_bug.part.1+0x60/0x60
[ 4856.602740]  rtrs_clt_rdma_done+0x3f7/0x670 [rtrs_client]
[ 4856.602804]  ? rtrs_clt_rdma_cm_handler+0xda0/0xda0 [rtrs_client]
[ 4856.602857]  ? check_flags.part.31+0x6c/0x1f0
[ 4856.602927]  ? rcu_read_lock_sched_held+0xaf/0xe0
[ 4856.602963]  ? rcu_read_lock_bh_held+0xc0/0xc0
[ 4856.603137]  __ib_process_cq+0x10a/0x350 [ib_core]
[ 4856.603309]  ib_poll_handler+0x41/0x1c0 [ib_core]
[ 4856.603358]  irq_poll_softirq+0xe6/0x280
[ 4856.603392]  ? lockdep_hardirqs_on_prepare+0x111/0x210
[ 4856.603446]  __do_softirq+0x10d/0x646
[ 4856.603540]  asm_call_irq_on_stack+0x12/0x20
[ 4856.603563]  </IRQ>

[ 4856.605096] Allocated by task 8914:
[ 4856.605510]  kasan_save_stack+0x19/0x40
[ 4856.605532]  __kasan_kmalloc.constprop.7+0xc1/0xd0
[ 4856.605552]  __kmalloc+0x155/0x320
[ 4856.605574]  __sg_alloc_table+0x155/0x1c0
[ 4856.605594]  sg_alloc_table+0x1f/0x50
[ 4856.605620]  send_msg_sess_info+0x119/0x2e0 [rnbd_client]
[ 4856.605646]  remap_devs+0x71/0x210 [rnbd_client]
[ 4856.605676]  init_sess+0xad8/0xe10 [rtrs_client]
[ 4856.605706]  rtrs_clt_reconnect_work+0xd6/0x170 [rtrs_client]
[ 4856.605728]  process_one_work+0x521/0xa90
[ 4856.605748]  worker_thread+0x65/0x5b0
[ 4856.605769]  kthread+0x1f2/0x210
[ 4856.605789]  ret_from_fork+0x22/0x30

[ 4856.606159] Freed by task 8914:
[ 4856.606559]  kasan_save_stack+0x19/0x40
[ 4856.606580]  kasan_set_track+0x1c/0x30
[ 4856.606601]  kasan_set_free_info+0x1b/0x30
[ 4856.606622]  __kasan_slab_free+0x108/0x150
[ 4856.606642]  slab_free_freelist_hook+0x64/0x190
[ 4856.606661]  kfree+0xe2/0x650
[ 4856.606681]  __sg_free_table+0xa4/0x100
[ 4856.606707]  send_msg_sess_info+0x1d6/0x2e0 [rnbd_client]
[ 4856.606733]  remap_devs+0x71/0x210 [rnbd_client]
[ 4856.606763]  init_sess+0xad8/0xe10 [rtrs_client]
[ 4856.606792]  rtrs_clt_reconnect_work+0xd6/0x170 [rtrs_client]
[ 4856.606813]  process_one_work+0x521/0xa90
[ 4856.606833]  worker_thread+0x65/0x5b0
[ 4856.606853]  kthread+0x1f2/0x210
[ 4856.606872]  ret_from_fork+0x22/0x30

The solution is to free iu's sgtable after the iu is not used anymore.
And also move sg_alloc_table into rnbd_get_iu accordingly.

Fixes: 5a1328d0c3a7 ("block/rnbd-clt: Dynamically allocate sglist for rnbd_iu")
Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block/rnbd-srv: Fix use after free in rnbd_srv_sess_dev_force_close 2021-01-08T15:19:18+00:00 Jack Wang jinpu.wang@cloud.ionos.com 2021-01-08T14:36:31+00:00 1a84e7c629f8f288e02236bc799f9b0be1cab4a7 KASAN detect following BUG: [ 778.215311] ================================================================== [ 778.216696] BUG: KASAN: use-after-free in rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server] [ 778.219037] Read of size 8 at addr ffff88b1d6516c28 by task tee/8842 [ 778.220500] CPU: 37 PID: 8842 Comm: tee Kdump: loaded Not tainted 5.10.0-pserver #5.10.0-1+feature+linux+next+20201214.1025+0910d71 [ 778.220529] Hardware name: Supermicro Super Server/X11DDW-L, BIOS 3.3 02/21/2020 [ 778.220555] Call Trace: [ 778.220609] dump_stack+0x99/0xcb [ 778.220667] ? rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server] [ 778.220715] print_address_description.constprop.7+0x1e/0x230 [ 778.220750] ? freeze_kernel_threads+0x73/0x73 [ 778.220896] ? rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server] [ 778.220932] ? rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server] [ 778.220994] kasan_report.cold.9+0x37/0x7c [ 778.221066] ? kobject_put+0x80/0x270 [ 778.221102] ? rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server] [ 778.221184] rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server] [ 778.221240] rnbd_srv_dev_session_force_close_store+0x6a/0xc0 [rnbd_server] [ 778.221304] ? sysfs_file_ops+0x90/0x90 [ 778.221353] kernfs_fop_write+0x141/0x240 [ 778.221451] vfs_write+0x142/0x4d0 [ 778.221553] ksys_write+0xc0/0x160 [ 778.221602] ? __ia32_sys_read+0x50/0x50 [ 778.221684] ? lockdep_hardirqs_on_prepare+0x13d/0x210 [ 778.221718] ? syscall_enter_from_user_mode+0x1c/0x50 [ 778.221821] do_syscall_64+0x33/0x40 [ 778.221862] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 778.221896] RIP: 0033:0x7f4affdd9504 [ 778.221928] Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00 48 8d 05 f9 61 0d 00 8b 00 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 41 54 49 89 d4 55 48 89 f5 53 [ 778.221956] RSP: 002b:00007fffebb36b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 778.222011] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f4affdd9504 [ 778.222038] RDX: 0000000000000002 RSI: 00007fffebb36c50 RDI: 0000000000000003 [ 778.222066] RBP: 00007fffebb36c50 R08: 0000556a151aa600 R09: 00007f4affeb1540 [ 778.222094] R10: fffffffffffffc19 R11: 0000000000000246 R12: 0000556a151aa520 [ 778.222121] R13: 0000000000000002 R14: 00007f4affea6760 R15: 0000000000000002 [ 778.222764] Allocated by task 3212: [ 778.223285] kasan_save_stack+0x19/0x40 [ 778.223316] __kasan_kmalloc.constprop.7+0xc1/0xd0 [ 778.223347] kmem_cache_alloc_trace+0x186/0x350 [ 778.223382] rnbd_srv_rdma_ev+0xf16/0x1690 [rnbd_server] [ 778.223422] process_io_req+0x4d1/0x670 [rtrs_server] [ 778.223573] __ib_process_cq+0x10a/0x350 [ib_core] [ 778.223709] ib_cq_poll_work+0x31/0xb0 [ib_core] [ 778.223743] process_one_work+0x521/0xa90 [ 778.223773] worker_thread+0x65/0x5b0 [ 778.223802] kthread+0x1f2/0x210 [ 778.223833] ret_from_fork+0x22/0x30 [ 778.224296] Freed by task 8842: [ 778.224800] kasan_save_stack+0x19/0x40 [ 778.224829] kasan_set_track+0x1c/0x30 [ 778.224860] kasan_set_free_info+0x1b/0x30 [ 778.224889] __kasan_slab_free+0x108/0x150 [ 778.224919] slab_free_freelist_hook+0x64/0x190 [ 778.224947] kfree+0xe2/0x650 [ 778.224982] rnbd_destroy_sess_dev+0x2fa/0x3b0 [rnbd_server] [ 778.225011] kobject_put+0xda/0x270 [ 778.225046] rnbd_srv_sess_dev_force_close+0x30/0x60 [rnbd_server] [ 778.225081] rnbd_srv_dev_session_force_close_store+0x6a/0xc0 [rnbd_server] [ 778.225111] kernfs_fop_write+0x141/0x240 [ 778.225140] vfs_write+0x142/0x4d0 [ 778.225169] ksys_write+0xc0/0x160 [ 778.225198] do_syscall_64+0x33/0x40 [ 778.225227] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 778.226506] The buggy address belongs to the object at ffff88b1d6516c00 which belongs to the cache kmalloc-512 of size 512 [ 778.227464] The buggy address is located 40 bytes inside of 512-byte region [ffff88b1d6516c00, ffff88b1d6516e00) The problem is in the sess_dev release function we call rnbd_destroy_sess_dev, and could free the sess_dev already, but we still set the keep_id in rnbd_srv_sess_dev_force_close, which lead to use after free. To fix it, move the keep_id before the sysfs removal, and cache the rnbd_srv_session for lock accessing, Fixes: 786998050cbc ("block/rnbd-srv: close a mapped device from server side.") Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com> Reviewed-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
KASAN detect following BUG:
[  778.215311] ==================================================================
[  778.216696] BUG: KASAN: use-after-free in rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server]
[  778.219037] Read of size 8 at addr ffff88b1d6516c28 by task tee/8842

[  778.220500] CPU: 37 PID: 8842 Comm: tee Kdump: loaded Not tainted 5.10.0-pserver #5.10.0-1+feature+linux+next+20201214.1025+0910d71
[  778.220529] Hardware name: Supermicro Super Server/X11DDW-L, BIOS 3.3 02/21/2020
[  778.220555] Call Trace:
[  778.220609]  dump_stack+0x99/0xcb
[  778.220667]  ? rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server]
[  778.220715]  print_address_description.constprop.7+0x1e/0x230
[  778.220750]  ? freeze_kernel_threads+0x73/0x73
[  778.220896]  ? rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server]
[  778.220932]  ? rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server]
[  778.220994]  kasan_report.cold.9+0x37/0x7c
[  778.221066]  ? kobject_put+0x80/0x270
[  778.221102]  ? rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server]
[  778.221184]  rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server]
[  778.221240]  rnbd_srv_dev_session_force_close_store+0x6a/0xc0 [rnbd_server]
[  778.221304]  ? sysfs_file_ops+0x90/0x90
[  778.221353]  kernfs_fop_write+0x141/0x240
[  778.221451]  vfs_write+0x142/0x4d0
[  778.221553]  ksys_write+0xc0/0x160
[  778.221602]  ? __ia32_sys_read+0x50/0x50
[  778.221684]  ? lockdep_hardirqs_on_prepare+0x13d/0x210
[  778.221718]  ? syscall_enter_from_user_mode+0x1c/0x50
[  778.221821]  do_syscall_64+0x33/0x40
[  778.221862]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  778.221896] RIP: 0033:0x7f4affdd9504
[  778.221928] Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00 48 8d 05 f9 61 0d 00 8b 00 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 41 54 49 89 d4 55 48 89 f5 53
[  778.221956] RSP: 002b:00007fffebb36b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[  778.222011] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f4affdd9504
[  778.222038] RDX: 0000000000000002 RSI: 00007fffebb36c50 RDI: 0000000000000003
[  778.222066] RBP: 00007fffebb36c50 R08: 0000556a151aa600 R09: 00007f4affeb1540
[  778.222094] R10: fffffffffffffc19 R11: 0000000000000246 R12: 0000556a151aa520
[  778.222121] R13: 0000000000000002 R14: 00007f4affea6760 R15: 0000000000000002

[  778.222764] Allocated by task 3212:
[  778.223285]  kasan_save_stack+0x19/0x40
[  778.223316]  __kasan_kmalloc.constprop.7+0xc1/0xd0
[  778.223347]  kmem_cache_alloc_trace+0x186/0x350
[  778.223382]  rnbd_srv_rdma_ev+0xf16/0x1690 [rnbd_server]
[  778.223422]  process_io_req+0x4d1/0x670 [rtrs_server]
[  778.223573]  __ib_process_cq+0x10a/0x350 [ib_core]
[  778.223709]  ib_cq_poll_work+0x31/0xb0 [ib_core]
[  778.223743]  process_one_work+0x521/0xa90
[  778.223773]  worker_thread+0x65/0x5b0
[  778.223802]  kthread+0x1f2/0x210
[  778.223833]  ret_from_fork+0x22/0x30

[  778.224296] Freed by task 8842:
[  778.224800]  kasan_save_stack+0x19/0x40
[  778.224829]  kasan_set_track+0x1c/0x30
[  778.224860]  kasan_set_free_info+0x1b/0x30
[  778.224889]  __kasan_slab_free+0x108/0x150
[  778.224919]  slab_free_freelist_hook+0x64/0x190
[  778.224947]  kfree+0xe2/0x650
[  778.224982]  rnbd_destroy_sess_dev+0x2fa/0x3b0 [rnbd_server]
[  778.225011]  kobject_put+0xda/0x270
[  778.225046]  rnbd_srv_sess_dev_force_close+0x30/0x60 [rnbd_server]
[  778.225081]  rnbd_srv_dev_session_force_close_store+0x6a/0xc0 [rnbd_server]
[  778.225111]  kernfs_fop_write+0x141/0x240
[  778.225140]  vfs_write+0x142/0x4d0
[  778.225169]  ksys_write+0xc0/0x160
[  778.225198]  do_syscall_64+0x33/0x40
[  778.225227]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

[  778.226506] The buggy address belongs to the object at ffff88b1d6516c00
                which belongs to the cache kmalloc-512 of size 512
[  778.227464] The buggy address is located 40 bytes inside of
                512-byte region [ffff88b1d6516c00, ffff88b1d6516e00)

The problem is in the sess_dev release function we call
rnbd_destroy_sess_dev, and could free the sess_dev already, but we still
set the keep_id in rnbd_srv_sess_dev_force_close, which lead to use
after free.

To fix it, move the keep_id before the sysfs removal, and cache the
rnbd_srv_session for lock accessing,

Fixes: 786998050cbc ("block/rnbd-srv: close a mapped device from server side.")
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Reviewed-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block/rnbd: Select SG_POOL for RNBD_CLIENT 2021-01-08T15:19:18+00:00 Jack Wang jinpu.wang@cloud.ionos.com 2021-01-08T14:36:30+00:00 74acfa996b2aec2a4ea8587104c7e2f8d4c6aec2 lkp reboot following build error: drivers/block/rnbd/rnbd-clt.c: In function 'rnbd_softirq_done_fn': >> drivers/block/rnbd/rnbd-clt.c:387:2: error: implicit declaration of function 'sg_free_table_chained' [-Werror=implicit-function-declaration] 387 | sg_free_table_chained(&iu->sgt, RNBD_INLINE_SG_CNT); | ^~~~~~~~~~~~~~~~~~~~~ The reason is CONFIG_SG_POOL is not enabled in the config, to avoid such failure, select SG_POOL in Kconfig for RNBD_CLIENT. Fixes: 5a1328d0c3a7 ("block/rnbd-clt: Dynamically allocate sglist for rnbd_iu") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
lkp reboot following build error:
 drivers/block/rnbd/rnbd-clt.c: In function 'rnbd_softirq_done_fn':
>> drivers/block/rnbd/rnbd-clt.c:387:2: error: implicit declaration of function 'sg_free_table_chained' [-Werror=implicit-function-declaration]
     387 |  sg_free_table_chained(&iu->sgt, RNBD_INLINE_SG_CNT);
         |  ^~~~~~~~~~~~~~~~~~~~~

The reason is CONFIG_SG_POOL is not enabled in the config, to
avoid such failure, select SG_POOL in Kconfig for RNBD_CLIENT.

Fixes: 5a1328d0c3a7 ("block/rnbd-clt: Dynamically allocate sglist for rnbd_iu")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>