In the Linux kernel, the following vulnerability has been resolved: iommu/arm-smmu-v3: check return value after calling platform_get_resource() It will cause null-ptr-deref if platform_get_resource() returns NULL, we need check the return value.

In the Linux kernel, the following vulnerability has been resolved: f2fs: remove WARN_ON in f2fs_is_valid_blkaddr Syzbot triggers two WARNs in f2fs_is_valid_blkaddr and __is_bitmap_valid. For example, in f2fs_is_valid_blkaddr, if type is DATA_GENERIC_ENHANCE or DATA_GENERIC_ENHANCE_READ, it invokes WARN_ON if blkaddr is not in the right range. The call trace is as follows: f2fs_get_node_info+0x45f/0x1070 read_node_page+0x577/0x1190 __get_node_page.part.0+0x9e/0x10e0 __get_node_page f2fs_get_node_page+0x109/0x180 do_read_inode f2fs_iget+0x2a5/0x58b0 f2fs_fill_super+0x3b39/0x7ca0 Fix these two WARNs by replacing WARN_ON with dump_stack.

In the Linux kernel, the following vulnerability has been resolved: f2fs: avoid infinite loop to flush node pages xfstests/generic/475 can give EIO all the time which give an infinite loop to flush node page like below. Let's avoid it. [16418.518551] Call Trace: [16418.518553] ? dm_submit_bio+0x48/0x400 [16418.518574] ? submit_bio_checks+0x1ac/0x5a0 [16418.525207] __submit_bio+0x1a9/0x230 [16418.525210] ? kmem_cache_alloc+0x29e/0x3c0 [16418.525223] submit_bio_noacct+0xa8/0x2b0 [16418.525226] submit_bio+0x4d/0x130 [16418.525238] __submit_bio+0x49/0x310 [f2fs] [16418.525339] ? bio_add_page+0x6a/0x90 [16418.525344] f2fs_submit_page_bio+0x134/0x1f0 [f2fs] [16418.525365] read_node_page+0x125/0x1b0 [f2fs] [16418.525388] __get_node_page.part.0+0x58/0x3f0 [f2fs] [16418.525409] __get_node_page+0x2f/0x60 [f2fs] [16418.525431] f2fs_get_dnode_of_data+0x423/0x860 [f2fs] [16418.525452] ? asm_sysvec_apic_timer_interrupt+0x12/0x20 [16418.525458] ? __mod_memcg_state.part.0+0x2a/0x30 [16418.525465] ? __mod_memcg_lruvec_state+0x27/0x40 [16418.525467] ? __xa_set_mark+0x57/0x70 [16418.525472] f2fs_do_write_data_page+0x10e/0x7b0 [f2fs] [16418.525493] f2fs_write_single_data_page+0x555/0x830 [f2fs] [16418.525514] ? sysvec_apic_timer_interrupt+0x4e/0x90 [16418.525518] ? asm_sysvec_apic_timer_interrupt+0x12/0x20 [16418.525523] f2fs_write_cache_pages+0x303/0x880 [f2fs] [16418.525545] ? blk_flush_plug_list+0x47/0x100 [16418.525548] f2fs_write_data_pages+0xfd/0x320 [f2fs] [16418.525569] do_writepages+0xd5/0x210 [16418.525648] filemap_fdatawrite_wbc+0x7d/0xc0 [16418.525655] filemap_fdatawrite+0x50/0x70 [16418.525658] f2fs_sync_dirty_inodes+0xa4/0x230 [f2fs] [16418.525679] f2fs_write_checkpoint+0x16d/0x1720 [f2fs] [16418.525699] ? ttwu_do_wakeup+0x1c/0x160 [16418.525709] ? ttwu_do_activate+0x6d/0xd0 [16418.525711] ? __wait_for_common+0x11d/0x150 [16418.525715] kill_f2fs_super+0xca/0x100 [f2fs] [16418.525733] deactivate_locked_super+0x3b/0xb0 [16418.525739] deactivate_super+0x40/0x50 [16418.525741] cleanup_mnt+0x139/0x190 [16418.525747] __cleanup_mnt+0x12/0x20 [16418.525749] task_work_run+0x6d/0xa0 [16418.525765] exit_to_user_mode_prepare+0x1ad/0x1b0 [16418.525771] syscall_exit_to_user_mode+0x27/0x50 [16418.525774] do_syscall_64+0x48/0xc0 [16418.525776] entry_SYSCALL_64_after_hwframe+0x44/0xae

In the Linux kernel, the following vulnerability has been resolved: NFSv4: Don't hold the layoutget locks across multiple RPC calls When doing layoutget as part of the open() compound, we have to be careful to release the layout locks before we can call any further RPC calls, such as setattr(). The reason is that those calls could trigger a recall, which could deadlock.

In the Linux kernel, the following vulnerability has been resolved: drivers: staging: rtl8192e: Fix deadlock in rtllib_beacons_stop() There is a deadlock in rtllib_beacons_stop(), which is shown below: (Thread 1) | (Thread 2) | rtllib_send_beacon() rtllib_beacons_stop() | mod_timer() spin_lock_irqsave() //(1) | (wait a time) ... | rtllib_send_beacon_cb() del_timer_sync() | spin_lock_irqsave() //(2) (wait timer to stop) | ... We hold ieee->beacon_lock in position (1) of thread 1 and use del_timer_sync() to wait timer to stop, but timer handler also need ieee->beacon_lock in position (2) of thread 2. As a result, rtllib_beacons_stop() will block forever. This patch extracts del_timer_sync() from the protection of spin_lock_irqsave(), which could let timer handler to obtain the needed lock.

In the Linux kernel, the following vulnerability has been resolved: tty: Fix a possible resource leak in icom_probe When pci_read_config_dword failed, call pci_release_regions() and pci_disable_device() to recycle the resource previously allocated.

In the Linux kernel, the following vulnerability has been resolved: drivers: usb: host: Fix deadlock in oxu_bus_suspend() There is a deadlock in oxu_bus_suspend(), which is shown below: (Thread 1) | (Thread 2) | timer_action() oxu_bus_suspend() | mod_timer() spin_lock_irq() //(1) | (wait a time) ... | oxu_watchdog() del_timer_sync() | spin_lock_irq() //(2) (wait timer to stop) | ... We hold oxu->lock in position (1) of thread 1, and use del_timer_sync() to wait timer to stop, but timer handler also need oxu->lock in position (2) of thread 2. As a result, oxu_bus_suspend() will block forever. This patch extracts del_timer_sync() from the protection of spin_lock_irq(), which could let timer handler to obtain the needed lock.

In the Linux kernel, the following vulnerability has been resolved: staging: rtl8712: fix a potential memory leak in r871xu_drv_init() In r871xu_drv_init(), if r8712_init_drv_sw() fails, then the memory allocated by r8712_alloc_io_queue() in r8712_usb_dvobj_init() is not properly released as there is no action will be performed by r8712_usb_dvobj_deinit(). To properly release it, we should call r8712_free_io_queue() in r8712_usb_dvobj_deinit(). Besides, in r871xu_dev_remove(), r8712_usb_dvobj_deinit() will be called by r871x_dev_unload() under condition `padapter->bup` and r8712_free_io_queue() is called by r8712_free_drv_sw(). However, r8712_usb_dvobj_deinit() does not rely on `padapter->bup` and calling r8712_free_io_queue() in r8712_free_drv_sw() is negative for better understading the code. So I move r8712_usb_dvobj_deinit() into r871xu_dev_remove(), and remove r8712_free_io_queue() from r8712_free_drv_sw().

In the Linux kernel, the following vulnerability has been resolved: drivers: staging: rtl8192bs: Fix deadlock in rtw_joinbss_event_prehandle() There is a deadlock in rtw_joinbss_event_prehandle(), which is shown below: (Thread 1) | (Thread 2) | _set_timer() rtw_joinbss_event_prehandle()| mod_timer() spin_lock_bh() //(1) | (wait a time) ... | _rtw_join_timeout_handler() del_timer_sync() | spin_lock_bh() //(2) (wait timer to stop) | ... We hold pmlmepriv->lock in position (1) of thread 1 and use del_timer_sync() to wait timer to stop, but timer handler also need pmlmepriv->lock in position (2) of thread 2. As a result, rtw_joinbss_event_prehandle() will block forever. This patch extracts del_timer_sync() from the protection of spin_lock_bh(), which could let timer handler to obtain the needed lock. What`s more, we change spin_lock_bh() to spin_lock_irq() in _rtw_join_timeout_handler() in order to prevent deadlock.

In the Linux kernel, the following vulnerability has been resolved: drivers: staging: rtl8723bs: Fix deadlock in rtw_surveydone_event_callback() There is a deadlock in rtw_surveydone_event_callback(), which is shown below: (Thread 1) | (Thread 2) | _set_timer() rtw_surveydone_event_callback()| mod_timer() spin_lock_bh() //(1) | (wait a time) ... | rtw_scan_timeout_handler() del_timer_sync() | spin_lock_bh() //(2) (wait timer to stop) | ... We hold pmlmepriv->lock in position (1) of thread 1 and use del_timer_sync() to wait timer to stop, but timer handler also need pmlmepriv->lock in position (2) of thread 2. As a result, rtw_surveydone_event_callback() will block forever. This patch extracts del_timer_sync() from the protection of spin_lock_bh(), which could let timer handler to obtain the needed lock. What`s more, we change spin_lock_bh() in rtw_scan_timeout_handler() to spin_lock_irq(). Otherwise, spin_lock_bh() will also cause deadlock() in timer handler.

In the Linux kernel, the following vulnerability has been resolved: tty: synclink_gt: Fix null-pointer-dereference in slgt_clean() When the driver fails at alloc_hdlcdev(), and then we remove the driver module, we will get the following splat: [ 25.065966] general protection fault, probably for non-canonical address 0xdffffc0000000182: 0000 [#1] PREEMPT SMP KASAN PTI [ 25.066914] KASAN: null-ptr-deref in range [0x0000000000000c10-0x0000000000000c17] [ 25.069262] RIP: 0010:detach_hdlc_protocol+0x2a/0x3e0 [ 25.077709] Call Trace: [ 25.077924] <TASK> [ 25.078108] unregister_hdlc_device+0x16/0x30 [ 25.078481] slgt_cleanup+0x157/0x9f0 [synclink_gt] Fix this by checking whether the 'info->netdev' is a null pointer first.

In the Linux kernel, the following vulnerability has been resolved: drivers: staging: rtl8192u: Fix deadlock in ieee80211_beacons_stop() There is a deadlock in ieee80211_beacons_stop(), which is shown below: (Thread 1) | (Thread 2) | ieee80211_send_beacon() ieee80211_beacons_stop() | mod_timer() spin_lock_irqsave() //(1) | (wait a time) ... | ieee80211_send_beacon_cb() del_timer_sync() | spin_lock_irqsave() //(2) (wait timer to stop) | ... We hold ieee->beacon_lock in position (1) of thread 1 and use del_timer_sync() to wait timer to stop, but timer handler also need ieee->beacon_lock in position (2) of thread 2. As a result, ieee80211_beacons_stop() will block forever. This patch extracts del_timer_sync() from the protection of spin_lock_irqsave(), which could let timer handler to obtain the needed lock.

In the Linux kernel, the following vulnerability has been resolved: drivers: tty: serial: Fix deadlock in sa1100_set_termios() There is a deadlock in sa1100_set_termios(), which is shown below: (Thread 1) | (Thread 2) | sa1100_enable_ms() sa1100_set_termios() | mod_timer() spin_lock_irqsave() //(1) | (wait a time) ... | sa1100_timeout() del_timer_sync() | spin_lock_irqsave() //(2) (wait timer to stop) | ... We hold sport->port.lock in position (1) of thread 1 and use del_timer_sync() to wait timer to stop, but timer handler also need sport->port.lock in position (2) of thread 2. As a result, sa1100_set_termios() will block forever. This patch moves del_timer_sync() before spin_lock_irqsave() in order to prevent the deadlock.

In the Linux kernel, the following vulnerability has been resolved: drivers: staging: rtl8192eu: Fix deadlock in rtw_joinbss_event_prehandle There is a deadlock in rtw_joinbss_event_prehandle(), which is shown below: (Thread 1) | (Thread 2) | _set_timer() rtw_joinbss_event_prehandle()| mod_timer() spin_lock_bh() //(1) | (wait a time) ... | rtw_join_timeout_handler() | _rtw_join_timeout_handler() del_timer_sync() | spin_lock_bh() //(2) (wait timer to stop) | ... We hold pmlmepriv->lock in position (1) of thread 1 and use del_timer_sync() to wait timer to stop, but timer handler also need pmlmepriv->lock in position (2) of thread 2. As a result, rtw_joinbss_event_prehandle() will block forever. This patch extracts del_timer_sync() from the protection of spin_lock_bh(), which could let timer handler to obtain the needed lock. What`s more, we change spin_lock_bh() to spin_lock_irq() in _rtw_join_timeout_handler() in order to prevent deadlock.

In the Linux kernel, the following vulnerability has been resolved: USB: host: isp116x: check return value after calling platform_get_resource() It will cause null-ptr-deref if platform_get_resource() returns NULL, we need check the return value.

In the Linux kernel, the following vulnerability has been resolved: staging: rtl8712: fix uninit-value in usb_read8() and friends When r8712_usbctrl_vendorreq() returns negative, 'data' in usb_read{8,16,32} will not be initialized. BUG: KMSAN: uninit-value in string_nocheck lib/vsprintf.c:643 [inline] BUG: KMSAN: uninit-value in string+0x4ec/0x6f0 lib/vsprintf.c:725 string_nocheck lib/vsprintf.c:643 [inline] string+0x4ec/0x6f0 lib/vsprintf.c:725 vsnprintf+0x2222/0x3650 lib/vsprintf.c:2806 va_format lib/vsprintf.c:1704 [inline] pointer+0x18e6/0x1f70 lib/vsprintf.c:2443 vsnprintf+0x1a9b/0x3650 lib/vsprintf.c:2810 vprintk_store+0x537/0x2150 kernel/printk/printk.c:2158 vprintk_emit+0x28b/0xab0 kernel/printk/printk.c:2256 dev_vprintk_emit+0x5ef/0x6d0 drivers/base/core.c:4604 dev_printk_emit+0x1dd/0x21f drivers/base/core.c:4615 __dev_printk+0x3be/0x440 drivers/base/core.c:4627 _dev_info+0x1ea/0x22f drivers/base/core.c:4673 r871xu_drv_init+0x1929/0x3070 drivers/staging/rtl8712/usb_intf.c:401 usb_probe_interface+0xf19/0x1600 drivers/usb/core/driver.c:396 really_probe+0x6c7/0x1350 drivers/base/dd.c:621 __driver_probe_device+0x3e9/0x530 drivers/base/dd.c:752 driver_probe_device drivers/base/dd.c:782 [inline] __device_attach_driver+0x79f/0x1120 drivers/base/dd.c:899 bus_for_each_drv+0x2d6/0x3f0 drivers/base/bus.c:427 __device_attach+0x593/0x8e0 drivers/base/dd.c:970 device_initial_probe+0x4a/0x60 drivers/base/dd.c:1017 bus_probe_device+0x17b/0x3e0 drivers/base/bus.c:487 device_add+0x1fff/0x26e0 drivers/base/core.c:3405 usb_set_configuration+0x37e9/0x3ed0 drivers/usb/core/message.c:2170 usb_generic_driver_probe+0x13c/0x300 drivers/usb/core/generic.c:238 usb_probe_device+0x309/0x570 drivers/usb/core/driver.c:293 really_probe+0x6c7/0x1350 drivers/base/dd.c:621 __driver_probe_device+0x3e9/0x530 drivers/base/dd.c:752 driver_probe_device drivers/base/dd.c:782 [inline] __device_attach_driver+0x79f/0x1120 drivers/base/dd.c:899 bus_for_each_drv+0x2d6/0x3f0 drivers/base/bus.c:427 __device_attach+0x593/0x8e0 drivers/base/dd.c:970 device_initial_probe+0x4a/0x60 drivers/base/dd.c:1017 bus_probe_device+0x17b/0x3e0 drivers/base/bus.c:487 device_add+0x1fff/0x26e0 drivers/base/core.c:3405 usb_new_device+0x1b91/0x2950 drivers/usb/core/hub.c:2566 hub_port_connect drivers/usb/core/hub.c:5363 [inline] hub_port_connect_change drivers/usb/core/hub.c:5507 [inline] port_event drivers/usb/core/hub.c:5665 [inline] hub_event+0x58e3/0x89e0 drivers/usb/core/hub.c:5747 process_one_work+0xdb6/0x1820 kernel/workqueue.c:2289 worker_thread+0x10d0/0x2240 kernel/workqueue.c:2436 kthread+0x3c7/0x500 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 Local variable data created at: usb_read8+0x5d/0x130 drivers/staging/rtl8712/usb_ops.c:33 r8712_read8+0xa5/0xd0 drivers/staging/rtl8712/rtl8712_io.c:29 KMSAN: uninit-value in r871xu_drv_init https://syzkaller.appspot.com/bug?id=3cd92b1d85428b128503bfa7a250294c9ae00bd8

In the Linux kernel, the following vulnerability has been resolved: nbd: fix race between nbd_alloc_config() and module removal When nbd module is being removing, nbd_alloc_config() may be called concurrently by nbd_genl_connect(), although try_module_get() will return false, but nbd_alloc_config() doesn't handle it. The race may lead to the leak of nbd_config and its related resources (e.g, recv_workq) and oops in nbd_read_stat() due to the unload of nbd module as shown below: BUG: kernel NULL pointer dereference, address: 0000000000000040 Oops: 0000 [#1] SMP PTI CPU: 5 PID: 13840 Comm: kworker/u17:33 Not tainted 5.14.0+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) Workqueue: knbd16-recv recv_work [nbd] RIP: 0010:nbd_read_stat.cold+0x130/0x1a4 [nbd] Call Trace: recv_work+0x3b/0xb0 [nbd] process_one_work+0x1ed/0x390 worker_thread+0x4a/0x3d0 kthread+0x12a/0x150 ret_from_fork+0x22/0x30 Fixing it by checking the return value of try_module_get() in nbd_alloc_config(). As nbd_alloc_config() may return ERR_PTR(-ENODEV), assign nbd->config only when nbd_alloc_config() succeeds to ensure the value of nbd->config is binary (valid or NULL). Also adding a debug message to check the reference counter of nbd_config during module removal.

In the Linux kernel, the following vulnerability has been resolved: usb: dwc2: gadget: don't reset gadget's driver->bus UDC driver should not touch gadget's driver internals, especially it should not reset driver->bus. This wasn't harmful so far, but since commit fc274c1e9973 ("USB: gadget: Add a new bus for gadgets") gadget subsystem got it's own bus and messing with ->bus triggers the following NULL pointer dereference: dwc2 12480000.hsotg: bound driver g_ether 8<--- cut here --- Unable to handle kernel NULL pointer dereference at virtual address 00000000 [00000000] *pgd=00000000 Internal error: Oops: 5 [#1] SMP ARM Modules linked in: ... CPU: 0 PID: 620 Comm: modprobe Not tainted 5.18.0-rc5-next-20220504 #11862 Hardware name: Samsung Exynos (Flattened Device Tree) PC is at module_add_driver+0x44/0xe8 LR is at sysfs_do_create_link_sd+0x84/0xe0 ... Process modprobe (pid: 620, stack limit = 0x(ptrval)) ... module_add_driver from bus_add_driver+0xf4/0x1e4 bus_add_driver from driver_register+0x78/0x10c driver_register from usb_gadget_register_driver_owner+0x40/0xb4 usb_gadget_register_driver_owner from do_one_initcall+0x44/0x1e0 do_one_initcall from do_init_module+0x44/0x1c8 do_init_module from load_module+0x19b8/0x1b9c load_module from sys_finit_module+0xdc/0xfc sys_finit_module from ret_fast_syscall+0x0/0x54 Exception stack(0xf1771fa8 to 0xf1771ff0) ... dwc2 12480000.hsotg: new device is high-speed ---[ end trace 0000000000000000 ]--- Fix this by removing driver->bus entry reset.

In the Linux kernel, the following vulnerability has been resolved: staging: rtl8712: fix uninit-value in r871xu_drv_init() When 'tmpU1b' returns from r8712_read8(padapter, EE_9346CR) is 0, 'mac[6]' will not be initialized. BUG: KMSAN: uninit-value in r871xu_drv_init+0x2d54/0x3070 drivers/staging/rtl8712/usb_intf.c:541 r871xu_drv_init+0x2d54/0x3070 drivers/staging/rtl8712/usb_intf.c:541 usb_probe_interface+0xf19/0x1600 drivers/usb/core/driver.c:396 really_probe+0x653/0x14b0 drivers/base/dd.c:596 __driver_probe_device+0x3e9/0x530 drivers/base/dd.c:752 driver_probe_device drivers/base/dd.c:782 [inline] __device_attach_driver+0x79f/0x1120 drivers/base/dd.c:899 bus_for_each_drv+0x2d6/0x3f0 drivers/base/bus.c:427 __device_attach+0x593/0x8e0 drivers/base/dd.c:970 device_initial_probe+0x4a/0x60 drivers/base/dd.c:1017 bus_probe_device+0x17b/0x3e0 drivers/base/bus.c:487 device_add+0x1fff/0x26e0 drivers/base/core.c:3405 usb_set_configuration+0x37e9/0x3ed0 drivers/usb/core/message.c:2170 usb_generic_driver_probe+0x13c/0x300 drivers/usb/core/generic.c:238 usb_probe_device+0x309/0x570 drivers/usb/core/driver.c:293 really_probe+0x653/0x14b0 drivers/base/dd.c:596 __driver_probe_device+0x3e9/0x530 drivers/base/dd.c:752 driver_probe_device drivers/base/dd.c:782 [inline] __device_attach_driver+0x79f/0x1120 drivers/base/dd.c:899 bus_for_each_drv+0x2d6/0x3f0 drivers/base/bus.c:427 __device_attach+0x593/0x8e0 drivers/base/dd.c:970 device_initial_probe+0x4a/0x60 drivers/base/dd.c:1017 bus_probe_device+0x17b/0x3e0 drivers/base/bus.c:487 device_add+0x1fff/0x26e0 drivers/base/core.c:3405 usb_new_device+0x1b8e/0x2950 drivers/usb/core/hub.c:2566 hub_port_connect drivers/usb/core/hub.c:5358 [inline] hub_port_connect_change drivers/usb/core/hub.c:5502 [inline] port_event drivers/usb/core/hub.c:5660 [inline] hub_event+0x58e3/0x89e0 drivers/usb/core/hub.c:5742 process_one_work+0xdb6/0x1820 kernel/workqueue.c:2307 worker_thread+0x10b3/0x21e0 kernel/workqueue.c:2454 kthread+0x3c7/0x500 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 Local variable mac created at: r871xu_drv_init+0x1771/0x3070 drivers/staging/rtl8712/usb_intf.c:394 usb_probe_interface+0xf19/0x1600 drivers/usb/core/driver.c:396 KMSAN: uninit-value in r871xu_drv_init https://syzkaller.appspot.com/bug?id=3cd92b1d85428b128503bfa7a250294c9ae00bd8

In the Linux kernel, the following vulnerability has been resolved: ceph: fix possible deadlock when holding Fwb to get inline_data 1, mount with wsync. 2, create a file with O_RDWR, and the request was sent to mds.0: ceph_atomic_open()--> ceph_mdsc_do_request(openc) finish_open(file, dentry, ceph_open)--> ceph_open()--> ceph_init_file()--> ceph_init_file_info()--> ceph_uninline_data()--> { ... if (inline_version == 1 || /* initial version, no data */ inline_version == CEPH_INLINE_NONE) goto out_unlock; ... } The inline_version will be 1, which is the initial version for the new create file. And here the ci->i_inline_version will keep with 1, it's buggy. 3, buffer write to the file immediately: ceph_write_iter()--> ceph_get_caps(file, need=Fw, want=Fb, ...); generic_perform_write()--> a_ops->write_begin()--> ceph_write_begin()--> netfs_write_begin()--> netfs_begin_read()--> netfs_rreq_submit_slice()--> netfs_read_from_server()--> rreq->netfs_ops->issue_read()--> ceph_netfs_issue_read()--> { ... if (ci->i_inline_version != CEPH_INLINE_NONE && ceph_netfs_issue_op_inline(subreq)) return; ... } ceph_put_cap_refs(ci, Fwb); The ceph_netfs_issue_op_inline() will send a getattr(Fsr) request to mds.1. 4, then the mds.1 will request the rd lock for CInode::filelock from the auth mds.0, the mds.0 will do the CInode::filelock state transation from excl --> sync, but it need to revoke the Fxwb caps back from the clients. While the kernel client has aleady held the Fwb caps and waiting for the getattr(Fsr). It's deadlock! URL: https://tracker.ceph.com/issues/55377