A credentials leak flaw was found in OpenStack Barbican. This flaw allows a local authenticated attacker to read the configuration file, gaining access to sensitive credentials.

In the Linux kernel, the following vulnerability has been resolved: tcp: Fix a data-race around sysctl_tcp_ecn_fallback. While reading sysctl_tcp_ecn_fallback, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader.

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix deadlock between quota disable and qgroup rescan worker Quota disable ioctl starts a transaction before waiting for the qgroup rescan worker completes. However, this wait can be infinite and results in deadlock because of circular dependency among the quota disable ioctl, the qgroup rescan worker and the other task with transaction such as block group relocation task. The deadlock happens with the steps following: 1) Task A calls ioctl to disable quota. It starts a transaction and waits for qgroup rescan worker completes. 2) Task B such as block group relocation task starts a transaction and joins to the transaction that task A started. Then task B commits to the transaction. In this commit, task B waits for a commit by task A. 3) Task C as the qgroup rescan worker starts its job and starts a transaction. In this transaction start, task C waits for completion of the transaction that task A started and task B committed. This deadlock was found with fstests test case btrfs/115 and a zoned null_blk device. The test case enables and disables quota, and the block group reclaim was triggered during the quota disable by chance. The deadlock was also observed by running quota enable and disable in parallel with 'btrfs balance' command on regular null_blk devices. An example report of the deadlock: [372.469894] INFO: task kworker/u16:6:103 blocked for more than 122 seconds. [372.479944] Not tainted 5.16.0-rc8 #7 [372.485067] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [372.493898] task:kworker/u16:6 state:D stack: 0 pid: 103 ppid: 2 flags:0x00004000 [372.503285] Workqueue: btrfs-qgroup-rescan btrfs_work_helper [btrfs] [372.510782] Call Trace: [372.514092] <TASK> [372.521684] __schedule+0xb56/0x4850 [372.530104] ? io_schedule_timeout+0x190/0x190 [372.538842] ? lockdep_hardirqs_on+0x7e/0x100 [372.547092] ? _raw_spin_unlock_irqrestore+0x3e/0x60 [372.555591] schedule+0xe0/0x270 [372.561894] btrfs_commit_transaction+0x18bb/0x2610 [btrfs] [372.570506] ? btrfs_apply_pending_changes+0x50/0x50 [btrfs] [372.578875] ? free_unref_page+0x3f2/0x650 [372.585484] ? finish_wait+0x270/0x270 [372.591594] ? release_extent_buffer+0x224/0x420 [btrfs] [372.599264] btrfs_qgroup_rescan_worker+0xc13/0x10c0 [btrfs] [372.607157] ? lock_release+0x3a9/0x6d0 [372.613054] ? btrfs_qgroup_account_extent+0xda0/0xda0 [btrfs] [372.620960] ? do_raw_spin_lock+0x11e/0x250 [372.627137] ? rwlock_bug.part.0+0x90/0x90 [372.633215] ? lock_is_held_type+0xe4/0x140 [372.639404] btrfs_work_helper+0x1ae/0xa90 [btrfs] [372.646268] process_one_work+0x7e9/0x1320 [372.652321] ? lock_release+0x6d0/0x6d0 [372.658081] ? pwq_dec_nr_in_flight+0x230/0x230 [372.664513] ? rwlock_bug.part.0+0x90/0x90 [372.670529] worker_thread+0x59e/0xf90 [372.676172] ? process_one_work+0x1320/0x1320 [372.682440] kthread+0x3b9/0x490 [372.687550] ? _raw_spin_unlock_irq+0x24/0x50 [372.693811] ? set_kthread_struct+0x100/0x100 [372.700052] ret_from_fork+0x22/0x30 [372.705517] </TASK> [372.709747] INFO: task btrfs-transacti:2347 blocked for more than 123 seconds. [372.729827] Not tainted 5.16.0-rc8 #7 [372.745907] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [372.767106] task:btrfs-transacti state:D stack: 0 pid: 2347 ppid: 2 flags:0x00004000 [372.787776] Call Trace: [372.801652] <TASK> [372.812961] __schedule+0xb56/0x4850 [372.830011] ? io_schedule_timeout+0x190/0x190 [372.852547] ? lockdep_hardirqs_on+0x7e/0x100 [372.871761] ? _raw_spin_unlock_irqrestore+0x3e/0x60 [372.886792] schedule+0xe0/0x270 [372.901685] wait_current_trans+0x22c/0x310 [btrfs] [372.919743] ? btrfs_put_transaction+0x3d0/0x3d0 [btrfs] [372.938923] ? finish_wait+0x270/0x270 [372.959085] ? join_transaction+0xc7 ---truncated---

In the Linux kernel, the following vulnerability has been resolved: igmp: Fix data-races around sysctl_igmp_llm_reports. While reading sysctl_igmp_llm_reports, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. This test can be packed into a helper, so such changes will be in the follow-up series after net is merged into net-next. if (ipv4_is_local_multicast(pmc->multiaddr) && !READ_ONCE(net->ipv4.sysctl_igmp_llm_reports))

In the Linux kernel, the following vulnerability has been resolved: tcp: Fix a data-race around sysctl_tcp_notsent_lowat. While reading sysctl_tcp_notsent_lowat, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader.

In the Linux kernel, the following vulnerability has been resolved: driver core: fix deadlock in __device_attach In __device_attach function, The lock holding logic is as follows: ... __device_attach device_lock(dev) // get lock dev async_schedule_dev(__device_attach_async_helper, dev); // func async_schedule_node async_schedule_node_domain(func) entry = kzalloc(sizeof(struct async_entry), GFP_ATOMIC); /* when fail or work limit, sync to execute func, but __device_attach_async_helper will get lock dev as well, which will lead to A-A deadlock. */ if (!entry || atomic_read(&entry_count) > MAX_WORK) { func; else queue_work_node(node, system_unbound_wq, &entry->work) device_unlock(dev) As shown above, when it is allowed to do async probes, because of out of memory or work limit, async work is not allowed, to do sync execute instead. it will lead to A-A deadlock because of __device_attach_async_helper getting lock dev. To fix the deadlock, move the async_schedule_dev outside device_lock, as we can see, in async_schedule_node_domain, the parameter of queue_work_node is system_unbound_wq, so it can accept concurrent operations. which will also not change the code logic, and will not lead to deadlock.

In the Linux kernel, the following vulnerability has been resolved: mm: vmscan: remove deadlock due to throttling failing to make progress A soft lockup bug in kcompactd was reported in a private bugzilla with the following visible in dmesg; watchdog: BUG: soft lockup - CPU#33 stuck for 26s! [kcompactd0:479] watchdog: BUG: soft lockup - CPU#33 stuck for 52s! [kcompactd0:479] watchdog: BUG: soft lockup - CPU#33 stuck for 78s! [kcompactd0:479] watchdog: BUG: soft lockup - CPU#33 stuck for 104s! [kcompactd0:479] The machine had 256G of RAM with no swap and an earlier failed allocation indicated that node 0 where kcompactd was run was potentially unreclaimable; Node 0 active_anon:29355112kB inactive_anon:2913528kB active_file:0kB inactive_file:0kB unevictable:64kB isolated(anon):0kB isolated(file):0kB mapped:8kB dirty:0kB writeback:0kB shmem:26780kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 23480320kB writeback_tmp:0kB kernel_stack:2272kB pagetables:24500kB all_unreclaimable? yes Vlastimil Babka investigated a crash dump and found that a task migrating pages was trying to drain PCP lists; PID: 52922 TASK: ffff969f820e5000 CPU: 19 COMMAND: "kworker/u128:3" Call Trace: __schedule schedule schedule_timeout wait_for_completion __flush_work __drain_all_pages __alloc_pages_slowpath.constprop.114 __alloc_pages alloc_migration_target migrate_pages migrate_to_node do_migrate_pages cpuset_migrate_mm_workfn process_one_work worker_thread kthread ret_from_fork This failure is specific to CONFIG_PREEMPT=n builds. The root of the problem is that kcompact0 is not rescheduling on a CPU while a task that has isolated a large number of the pages from the LRU is waiting on kcompact0 to reschedule so the pages can be released. While shrink_inactive_list() only loops once around too_many_isolated, reclaim can continue without rescheduling if sc->skipped_deactivate == 1 which could happen if there was no file LRU and the inactive anon list was not low.

In the Linux kernel, the following vulnerability has been resolved: drm/msm/dp: do not complete dp_aux_cmd_fifo_tx() if irq is not for aux transfer There are 3 possible interrupt sources are handled by DP controller, HPDstatus, Controller state changes and Aux read/write transaction. At every irq, DP controller have to check isr status of every interrupt sources and service the interrupt if its isr status bits shows interrupts are pending. There is potential race condition may happen at current aux isr handler implementation since it is always complete dp_aux_cmd_fifo_tx() even irq is not for aux read or write transaction. This may cause aux read transaction return premature if host aux data read is in the middle of waiting for sink to complete transferring data to host while irq happen. This will cause host's receiving buffer contains unexpected data. This patch fixes this problem by checking aux isr and return immediately at aux isr handler if there are no any isr status bits set. Current there is a bug report regrading eDP edid corruption happen during system booting up. After lengthy debugging to found that VIDEO_READY interrupt was continuously firing during system booting up which cause dp_aux_isr() to complete dp_aux_cmd_fifo_tx() prematurely to retrieve data from aux hardware buffer which is not yet contains complete data transfer from sink. This cause edid corruption. Follows are the signature at kernel logs when problem happen, EDID has corrupt header panel-simple-dp-aux aux-aea0000.edp: Couldn't identify panel via EDID Changes in v2: -- do complete if (ret == IRQ_HANDLED) ay dp-aux_isr() -- add more commit text Changes in v3: -- add Stephen suggested -- dp_aux_isr() return IRQ_XXX back to caller -- dp_ctrl_isr() return IRQ_XXX back to caller Changes in v4: -- split into two patches Changes in v5: -- delete empty line between tags Changes in v6: -- remove extra "that" and fixed line more than 75 char at commit text Patchwork: https://patchwork.freedesktop.org/patch/516121/

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: 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: ip: Fix a data-race around sysctl_fwmark_reflect. While reading sysctl_fwmark_reflect, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader.

In the Linux kernel, the following vulnerability has been resolved: tcp: Fix data-races around sysctl_tcp_slow_start_after_idle. While reading sysctl_tcp_slow_start_after_idle, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers.

In the Linux kernel, the following vulnerability has been resolved: tcp: Fix data-races around sysctl_tcp_recovery. While reading sysctl_tcp_recovery, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers.

In the Linux kernel, the following vulnerability has been resolved: tcp/dccp: Fix a data-race around sysctl_tcp_fwmark_accept. While reading sysctl_tcp_fwmark_accept, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader.

In the Linux kernel, the following vulnerability has been resolved: tcp: Fix data-races around sysctl_tcp_l3mdev_accept. While reading sysctl_tcp_l3mdev_accept, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers.

In the Linux kernel, the following vulnerability has been resolved: ipv4: Fix data-races around sysctl_fib_multipath_hash_fields. While reading sysctl_fib_multipath_hash_fields, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers.

In the Linux kernel, the following vulnerability has been resolved: ip: Fix data-races around sysctl_ip_fwd_update_priority. While reading sysctl_ip_fwd_update_priority, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers.

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: loop: implement ->free_disk Ensure that the lo_device which is stored in the gendisk private data is valid until the gendisk is freed. Currently the loop driver uses a lot of effort to make sure a device is not freed when it is still in use, but to to fix a potential deadlock this will be relaxed a bit soon.

In the Linux kernel, the following vulnerability has been resolved: ice: Fix race condition during interface enslave Commit 5dbbbd01cbba83 ("ice: Avoid RTNL lock when re-creating auxiliary device") changes a process of re-creation of aux device so ice_plug_aux_dev() is called from ice_service_task() context. This unfortunately opens a race window that can result in dead-lock when interface has left LAG and immediately enters LAG again. Reproducer: ``` #!/bin/sh ip link add lag0 type bond mode 1 miimon 100 ip link set lag0 for n in {1..10}; do echo Cycle: $n ip link set ens7f0 master lag0 sleep 1 ip link set ens7f0 nomaster done ``` This results in: [20976.208697] Workqueue: ice ice_service_task [ice] [20976.213422] Call Trace: [20976.215871] __schedule+0x2d1/0x830 [20976.219364] schedule+0x35/0xa0 [20976.222510] schedule_preempt_disabled+0xa/0x10 [20976.227043] __mutex_lock.isra.7+0x310/0x420 [20976.235071] enum_all_gids_of_dev_cb+0x1c/0x100 [ib_core] [20976.251215] ib_enum_roce_netdev+0xa4/0xe0 [ib_core] [20976.256192] ib_cache_setup_one+0x33/0xa0 [ib_core] [20976.261079] ib_register_device+0x40d/0x580 [ib_core] [20976.266139] irdma_ib_register_device+0x129/0x250 [irdma] [20976.281409] irdma_probe+0x2c1/0x360 [irdma] [20976.285691] auxiliary_bus_probe+0x45/0x70 [20976.289790] really_probe+0x1f2/0x480 [20976.298509] driver_probe_device+0x49/0xc0 [20976.302609] bus_for_each_drv+0x79/0xc0 [20976.306448] __device_attach+0xdc/0x160 [20976.310286] bus_probe_device+0x9d/0xb0 [20976.314128] device_add+0x43c/0x890 [20976.321287] __auxiliary_device_add+0x43/0x60 [20976.325644] ice_plug_aux_dev+0xb2/0x100 [ice] [20976.330109] ice_service_task+0xd0c/0xed0 [ice] [20976.342591] process_one_work+0x1a7/0x360 [20976.350536] worker_thread+0x30/0x390 [20976.358128] kthread+0x10a/0x120 [20976.365547] ret_from_fork+0x1f/0x40 ... [20976.438030] task:ip state:D stack: 0 pid:213658 ppid:213627 flags:0x00004084 [20976.446469] Call Trace: [20976.448921] __schedule+0x2d1/0x830 [20976.452414] schedule+0x35/0xa0 [20976.455559] schedule_preempt_disabled+0xa/0x10 [20976.460090] __mutex_lock.isra.7+0x310/0x420 [20976.464364] device_del+0x36/0x3c0 [20976.467772] ice_unplug_aux_dev+0x1a/0x40 [ice] [20976.472313] ice_lag_event_handler+0x2a2/0x520 [ice] [20976.477288] notifier_call_chain+0x47/0x70 [20976.481386] __netdev_upper_dev_link+0x18b/0x280 [20976.489845] bond_enslave+0xe05/0x1790 [bonding] [20976.494475] do_setlink+0x336/0xf50 [20976.502517] __rtnl_newlink+0x529/0x8b0 [20976.543441] rtnl_newlink+0x43/0x60 [20976.546934] rtnetlink_rcv_msg+0x2b1/0x360 [20976.559238] netlink_rcv_skb+0x4c/0x120 [20976.563079] netlink_unicast+0x196/0x230 [20976.567005] netlink_sendmsg+0x204/0x3d0 [20976.570930] sock_sendmsg+0x4c/0x50 [20976.574423] ____sys_sendmsg+0x1eb/0x250 [20976.586807] ___sys_sendmsg+0x7c/0xc0 [20976.606353] __sys_sendmsg+0x57/0xa0 [20976.609930] do_syscall_64+0x5b/0x1a0 [20976.613598] entry_SYSCALL_64_after_hwframe+0x65/0xca 1. Command 'ip link ... set nomaster' causes that ice_plug_aux_dev() is called from ice_service_task() context, aux device is created and associated device->lock is taken. 2. Command 'ip link ... set master...' calls ice's notifier under RTNL lock and that notifier calls ice_unplug_aux_dev(). That function tries to take aux device->lock but this is already taken by ice_plug_aux_dev() in step 1 3. Later ice_plug_aux_dev() tries to take RTNL lock but this is already taken in step 2 4. Dead-lock The patch fixes this issue by following changes: - Bit ICE_FLAG_PLUG_AUX_DEV is kept to be set during ice_plug_aux_dev() call in ice_service_task() - The bit is checked in ice_clear_rdma_cap() and only if it is not set then ice_unplug_aux_dev() is called. If it is set (in other words plugging of aux device was requested and ice_plug_aux_dev() is potentially running) then the function only clears the ---truncated---

In the Linux kernel, the following vulnerability has been resolved: tcp: Fix a data-race around sysctl_tcp_probe_interval. While reading sysctl_tcp_probe_interval, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader.

In the Linux kernel, the following vulnerability has been resolved: ip: Fix data-races around sysctl_ip_fwd_use_pmtu. While reading sysctl_ip_fwd_use_pmtu, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers.

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: tcp: Fix data-races around sysctl_tcp_mtu_probing. While reading sysctl_tcp_mtu_probing, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers.

In the Linux kernel, the following vulnerability has been resolved: btrfs: get rid of warning on transaction commit when using flushoncommit When using the flushoncommit mount option, during almost every transaction commit we trigger a warning from __writeback_inodes_sb_nr(): $ cat fs/fs-writeback.c: (...) static void __writeback_inodes_sb_nr(struct super_block *sb, ... { (...) WARN_ON(!rwsem_is_locked(&sb->s_umount)); (...) } (...) The trace produced in dmesg looks like the following: [947.473890] WARNING: CPU: 5 PID: 930 at fs/fs-writeback.c:2610 __writeback_inodes_sb_nr+0x7e/0xb3 [947.481623] Modules linked in: nfsd nls_cp437 cifs asn1_decoder cifs_arc4 fscache cifs_md4 ipmi_ssif [947.489571] CPU: 5 PID: 930 Comm: btrfs-transacti Not tainted 95.16.3-srb-asrock-00001-g36437ad63879 #186 [947.497969] RIP: 0010:__writeback_inodes_sb_nr+0x7e/0xb3 [947.502097] Code: 24 10 4c 89 44 24 18 c6 (...) [947.519760] RSP: 0018:ffffc90000777e10 EFLAGS: 00010246 [947.523818] RAX: 0000000000000000 RBX: 0000000000963300 RCX: 0000000000000000 [947.529765] RDX: 0000000000000000 RSI: 000000000000fa51 RDI: ffffc90000777e50 [947.535740] RBP: ffff888101628a90 R08: ffff888100955800 R09: ffff888100956000 [947.541701] R10: 0000000000000002 R11: 0000000000000001 R12: ffff888100963488 [947.547645] R13: ffff888100963000 R14: ffff888112fb7200 R15: ffff888100963460 [947.553621] FS: 0000000000000000(0000) GS:ffff88841fd40000(0000) knlGS:0000000000000000 [947.560537] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [947.565122] CR2: 0000000008be50c4 CR3: 000000000220c000 CR4: 00000000001006e0 [947.571072] Call Trace: [947.572354] <TASK> [947.573266] btrfs_commit_transaction+0x1f1/0x998 [947.576785] ? start_transaction+0x3ab/0x44e [947.579867] ? schedule_timeout+0x8a/0xdd [947.582716] transaction_kthread+0xe9/0x156 [947.585721] ? btrfs_cleanup_transaction.isra.0+0x407/0x407 [947.590104] kthread+0x131/0x139 [947.592168] ? set_kthread_struct+0x32/0x32 [947.595174] ret_from_fork+0x22/0x30 [947.597561] </TASK> [947.598553] ---[ end trace 644721052755541c ]--- This is because we started using writeback_inodes_sb() to flush delalloc when committing a transaction (when using -o flushoncommit), in order to avoid deadlocks with filesystem freeze operations. This change was made by commit ce8ea7cc6eb313 ("btrfs: don't call btrfs_start_delalloc_roots in flushoncommit"). After that change we started producing that warning, and every now and then a user reports this since the warning happens too often, it spams dmesg/syslog, and a user is unsure if this reflects any problem that might compromise the filesystem's reliability. We can not just lock the sb->s_umount semaphore before calling writeback_inodes_sb(), because that would at least deadlock with filesystem freezing, since at fs/super.c:freeze_super() sync_filesystem() is called while we are holding that semaphore in write mode, and that can trigger a transaction commit, resulting in a deadlock. It would also trigger the same type of deadlock in the unmount path. Possibly, it could also introduce some other locking dependencies that lockdep would report. To fix this call try_to_writeback_inodes_sb() instead of writeback_inodes_sb(), because that will try to read lock sb->s_umount and then will only call writeback_inodes_sb() if it was able to lock it. This is fine because the cases where it can't read lock sb->s_umount are during a filesystem unmount or during a filesystem freeze - in those cases sb->s_umount is write locked and sync_filesystem() is called, which calls writeback_inodes_sb(). In other words, in all cases where we can't take a read lock on sb->s_umount, writeback is already being triggered elsewhere. An alternative would be to call btrfs_start_delalloc_roots() with a number of pages different from LONG_MAX, for example matching the number of delalloc bytes we currently have, in ---truncated---

In the Linux kernel, the following vulnerability has been resolved: ipv4: Fix data-races around sysctl_fib_multipath_hash_policy. While reading sysctl_fib_multipath_hash_policy, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers.

In the Linux kernel, the following vulnerability has been resolved: tcp: Fix data-races around sysctl_tcp_fastopen_blackhole_timeout. While reading sysctl_tcp_fastopen_blackhole_timeout, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers.

In the Linux kernel, the following vulnerability has been resolved: configfs: fix a race in configfs_{,un}register_subsystem() When configfs_register_subsystem() or configfs_unregister_subsystem() is executing link_group() or unlink_group(), it is possible that two processes add or delete list concurrently. Some unfortunate interleavings of them can cause kernel panic. One of cases is: A --> B --> C --> D A <-- B <-- C <-- D delete list_head *B | delete list_head *C --------------------------------|----------------------------------- configfs_unregister_subsystem | configfs_unregister_subsystem unlink_group | unlink_group unlink_obj | unlink_obj list_del_init | list_del_init __list_del_entry | __list_del_entry __list_del | __list_del // next == C | next->prev = prev | | next->prev = prev prev->next = next | | // prev == B | prev->next = next Fix this by adding mutex when calling link_group() or unlink_group(), but parent configfs_subsystem is NULL when config_item is root. So I create a mutex configfs_subsystem_mutex.

In the Linux kernel, the following vulnerability has been resolved: scsi: lpfc: Fix SCSI I/O completion and abort handler deadlock During stress I/O tests with 500+ vports, hard LOCKUP call traces are observed. CPU A: native_queued_spin_lock_slowpath+0x192 _raw_spin_lock_irqsave+0x32 lpfc_handle_fcp_err+0x4c6 lpfc_fcp_io_cmd_wqe_cmpl+0x964 lpfc_sli4_fp_handle_cqe+0x266 __lpfc_sli4_process_cq+0x105 __lpfc_sli4_hba_process_cq+0x3c lpfc_cq_poll_hdler+0x16 irq_poll_softirq+0x76 __softirqentry_text_start+0xe4 irq_exit+0xf7 do_IRQ+0x7f CPU B: native_queued_spin_lock_slowpath+0x5b _raw_spin_lock+0x1c lpfc_abort_handler+0x13e scmd_eh_abort_handler+0x85 process_one_work+0x1a7 worker_thread+0x30 kthread+0x112 ret_from_fork+0x1f Diagram of lockup: CPUA CPUB ---- ---- lpfc_cmd->buf_lock phba->hbalock lpfc_cmd->buf_lock phba->hbalock Fix by reordering the taking of the lpfc_cmd->buf_lock and phba->hbalock in lpfc_abort_handler routine so that it tries to take the lpfc_cmd->buf_lock first before phba->hbalock.

In the Linux kernel, the following vulnerability has been resolved: riscv: fix race when vmap stack overflow Currently, when detecting vmap stack overflow, riscv firstly switches to the so called shadow stack, then use this shadow stack to call the get_overflow_stack() to get the overflow stack. However, there's a race here if two or more harts use the same shadow stack at the same time. To solve this race, we introduce spin_shadow_stack atomic var, which will be swap between its own address and 0 in atomic way, when the var is set, it means the shadow_stack is being used; when the var is cleared, it means the shadow_stack isn't being used. [Palmer: Add AQ to the swap, and also some comments.]

In the Linux kernel, the following vulnerability has been resolved: list: fix a data-race around ep->rdllist ep_poll() first calls ep_events_available() with no lock held and checks if ep->rdllist is empty by list_empty_careful(), which reads rdllist->prev. Thus all accesses to it need some protection to avoid store/load-tearing. Note INIT_LIST_HEAD_RCU() already has the annotation for both prev and next. Commit bf3b9f6372c4 ("epoll: Add busy poll support to epoll with socket fds.") added the first lockless ep_events_available(), and commit c5a282e9635e ("fs/epoll: reduce the scope of wq lock in epoll_wait()") made some ep_events_available() calls lockless and added single call under a lock, finally commit e59d3c64cba6 ("epoll: eliminate unnecessary lock for zero timeout") made the last ep_events_available() lockless. BUG: KCSAN: data-race in do_epoll_wait / do_epoll_wait write to 0xffff88810480c7d8 of 8 bytes by task 1802 on cpu 0: INIT_LIST_HEAD include/linux/list.h:38 [inline] list_splice_init include/linux/list.h:492 [inline] ep_start_scan fs/eventpoll.c:622 [inline] ep_send_events fs/eventpoll.c:1656 [inline] ep_poll fs/eventpoll.c:1806 [inline] do_epoll_wait+0x4eb/0xf40 fs/eventpoll.c:2234 do_epoll_pwait fs/eventpoll.c:2268 [inline] __do_sys_epoll_pwait fs/eventpoll.c:2281 [inline] __se_sys_epoll_pwait+0x12b/0x240 fs/eventpoll.c:2275 __x64_sys_epoll_pwait+0x74/0x80 fs/eventpoll.c:2275 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff88810480c7d8 of 8 bytes by task 1799 on cpu 1: list_empty_careful include/linux/list.h:329 [inline] ep_events_available fs/eventpoll.c:381 [inline] ep_poll fs/eventpoll.c:1797 [inline] do_epoll_wait+0x279/0xf40 fs/eventpoll.c:2234 do_epoll_pwait fs/eventpoll.c:2268 [inline] __do_sys_epoll_pwait fs/eventpoll.c:2281 [inline] __se_sys_epoll_pwait+0x12b/0x240 fs/eventpoll.c:2275 __x64_sys_epoll_pwait+0x74/0x80 fs/eventpoll.c:2275 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0xffff88810480c7d0 -> 0xffff888103c15098 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 1799 Comm: syz-fuzzer Tainted: G W 5.17.0-rc7-syzkaller-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

In the Linux kernel, the following vulnerability has been resolved: ibmvnic: fix race between xmit and reset There is a race between reset and the transmit paths that can lead to ibmvnic_xmit() accessing an scrq after it has been freed in the reset path. It can result in a crash like: Kernel attempted to read user page (0) - exploit attempt? (uid: 0) BUG: Kernel NULL pointer dereference on read at 0x00000000 Faulting instruction address: 0xc0080000016189f8 Oops: Kernel access of bad area, sig: 11 [#1] ... NIP [c0080000016189f8] ibmvnic_xmit+0x60/0xb60 [ibmvnic] LR [c000000000c0046c] dev_hard_start_xmit+0x11c/0x280 Call Trace: [c008000001618f08] ibmvnic_xmit+0x570/0xb60 [ibmvnic] (unreliable) [c000000000c0046c] dev_hard_start_xmit+0x11c/0x280 [c000000000c9cfcc] sch_direct_xmit+0xec/0x330 [c000000000bfe640] __dev_xmit_skb+0x3a0/0x9d0 [c000000000c00ad4] __dev_queue_xmit+0x394/0x730 [c008000002db813c] __bond_start_xmit+0x254/0x450 [bonding] [c008000002db8378] bond_start_xmit+0x40/0xc0 [bonding] [c000000000c0046c] dev_hard_start_xmit+0x11c/0x280 [c000000000c00ca4] __dev_queue_xmit+0x564/0x730 [c000000000cf97e0] neigh_hh_output+0xd0/0x180 [c000000000cfa69c] ip_finish_output2+0x31c/0x5c0 [c000000000cfd244] __ip_queue_xmit+0x194/0x4f0 [c000000000d2a3c4] __tcp_transmit_skb+0x434/0x9b0 [c000000000d2d1e0] __tcp_retransmit_skb+0x1d0/0x6a0 [c000000000d2d984] tcp_retransmit_skb+0x34/0x130 [c000000000d310e8] tcp_retransmit_timer+0x388/0x6d0 [c000000000d315ec] tcp_write_timer_handler+0x1bc/0x330 [c000000000d317bc] tcp_write_timer+0x5c/0x200 [c000000000243270] call_timer_fn+0x50/0x1c0 [c000000000243704] __run_timers.part.0+0x324/0x460 [c000000000243894] run_timer_softirq+0x54/0xa0 [c000000000ea713c] __do_softirq+0x15c/0x3e0 [c000000000166258] __irq_exit_rcu+0x158/0x190 [c000000000166420] irq_exit+0x20/0x40 [c00000000002853c] timer_interrupt+0x14c/0x2b0 [c000000000009a00] decrementer_common_virt+0x210/0x220 --- interrupt: 900 at plpar_hcall_norets_notrace+0x18/0x2c The immediate cause of the crash is the access of tx_scrq in the following snippet during a reset, where the tx_scrq can be either NULL or an address that will soon be invalid: ibmvnic_xmit() { ... tx_scrq = adapter->tx_scrq[queue_num]; txq = netdev_get_tx_queue(netdev, queue_num); ind_bufp = &tx_scrq->ind_buf; if (test_bit(0, &adapter->resetting)) { ... } But beyond that, the call to ibmvnic_xmit() itself is not safe during a reset and the reset path attempts to avoid this by stopping the queue in ibmvnic_cleanup(). However just after the queue was stopped, an in-flight ibmvnic_complete_tx() could have restarted the queue even as the reset is progressing. Since the queue was restarted we could get a call to ibmvnic_xmit() which can then access the bad tx_scrq (or other fields). We cannot however simply have ibmvnic_complete_tx() check the ->resetting bit and skip starting the queue. This can race at the "back-end" of a good reset which just restarted the queue but has not cleared the ->resetting bit yet. If we skip restarting the queue due to ->resetting being true, the queue would remain stopped indefinitely potentially leading to transmit timeouts. IOW ->resetting is too broad for this purpose. Instead use a new flag that indicates whether or not the queues are active. Only the open/ reset paths control when the queues are active. ibmvnic_complete_tx() and others wake up the queue only if the queue is marked active. So we will have: A. reset/open thread in ibmvnic_cleanup() and __ibmvnic_open() ->resetting = true ->tx_queues_active = false disable tx queues ... ->tx_queues_active = true start tx queues B. Tx interrupt in ibmvnic_complete_tx(): if (->tx_queues_active) netif_wake_subqueue(); To ensure that ->tx_queues_active and state of the queues are consistent, we need a lock which: - must also be taken in the interrupt path (ibmvnic_complete_tx()) - shared across the multiple ---truncated---

In the Linux kernel, the following vulnerability has been resolved: io_uring: add a schedule point in io_add_buffers() Looping ~65535 times doing kmalloc() calls can trigger soft lockups, especially with DEBUG features (like KASAN). [ 253.536212] watchdog: BUG: soft lockup - CPU#64 stuck for 26s! [b219417889:12575] [ 253.544433] Modules linked in: vfat fat i2c_mux_pca954x i2c_mux spidev cdc_acm xhci_pci xhci_hcd sha3_generic gq(O) [ 253.544451] CPU: 64 PID: 12575 Comm: b219417889 Tainted: G S O 5.17.0-smp-DEV #801 [ 253.544457] RIP: 0010:kernel_text_address (./include/asm-generic/sections.h:192 ./include/linux/kallsyms.h:29 kernel/extable.c:67 kernel/extable.c:98) [ 253.544464] Code: 0f 93 c0 48 c7 c1 e0 63 d7 a4 48 39 cb 0f 92 c1 20 c1 0f b6 c1 5b 5d c3 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 53 48 89 fb <48> c7 c0 00 00 80 a0 41 be 01 00 00 00 48 39 c7 72 0c 48 c7 c0 40 [ 253.544468] RSP: 0018:ffff8882d8baf4c0 EFLAGS: 00000246 [ 253.544471] RAX: 1ffff1105b175e00 RBX: ffffffffa13ef09a RCX: 00000000a13ef001 [ 253.544474] RDX: ffffffffa13ef09a RSI: ffff8882d8baf558 RDI: ffffffffa13ef09a [ 253.544476] RBP: ffff8882d8baf4d8 R08: ffff8882d8baf5e0 R09: 0000000000000004 [ 253.544479] R10: ffff8882d8baf5e8 R11: ffffffffa0d59a50 R12: ffff8882eab20380 [ 253.544481] R13: ffffffffa0d59a50 R14: dffffc0000000000 R15: 1ffff1105b175eb0 [ 253.544483] FS: 00000000016d3380(0000) GS:ffff88af48c00000(0000) knlGS:0000000000000000 [ 253.544486] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 253.544488] CR2: 00000000004af0f0 CR3: 00000002eabfa004 CR4: 00000000003706e0 [ 253.544491] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 253.544492] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 253.544494] Call Trace: [ 253.544496] <TASK> [ 253.544498] ? io_queue_sqe (fs/io_uring.c:7143) [ 253.544505] __kernel_text_address (kernel/extable.c:78) [ 253.544508] unwind_get_return_address (arch/x86/kernel/unwind_frame.c:19) [ 253.544514] arch_stack_walk (arch/x86/kernel/stacktrace.c:27) [ 253.544517] ? io_queue_sqe (fs/io_uring.c:7143) [ 253.544521] stack_trace_save (kernel/stacktrace.c:123) [ 253.544527] ____kasan_kmalloc (mm/kasan/common.c:39 mm/kasan/common.c:45 mm/kasan/common.c:436 mm/kasan/common.c:515) [ 253.544531] ? ____kasan_kmalloc (mm/kasan/common.c:39 mm/kasan/common.c:45 mm/kasan/common.c:436 mm/kasan/common.c:515) [ 253.544533] ? __kasan_kmalloc (mm/kasan/common.c:524) [ 253.544535] ? kmem_cache_alloc_trace (./include/linux/kasan.h:270 mm/slab.c:3567) [ 253.544541] ? io_issue_sqe (fs/io_uring.c:4556 fs/io_uring.c:4589 fs/io_uring.c:6828) [ 253.544544] ? __io_queue_sqe (fs/io_uring.c:?) [ 253.544551] __kasan_kmalloc (mm/kasan/common.c:524) [ 253.544553] kmem_cache_alloc_trace (./include/linux/kasan.h:270 mm/slab.c:3567) [ 253.544556] ? io_issue_sqe (fs/io_uring.c:4556 fs/io_uring.c:4589 fs/io_uring.c:6828) [ 253.544560] io_issue_sqe (fs/io_uring.c:4556 fs/io_uring.c:4589 fs/io_uring.c:6828) [ 253.544564] ? __kasan_slab_alloc (mm/kasan/common.c:45 mm/kasan/common.c:436 mm/kasan/common.c:469) [ 253.544567] ? __kasan_slab_alloc (mm/kasan/common.c:39 mm/kasan/common.c:45 mm/kasan/common.c:436 mm/kasan/common.c:469) [ 253.544569] ? kmem_cache_alloc_bulk (mm/slab.h:732 mm/slab.c:3546) [ 253.544573] ? __io_alloc_req_refill (fs/io_uring.c:2078) [ 253.544578] ? io_submit_sqes (fs/io_uring.c:7441) [ 253.544581] ? __se_sys_io_uring_enter (fs/io_uring.c:10154 fs/io_uring.c:10096) [ 253.544584] ? __x64_sys_io_uring_enter (fs/io_uring.c:10096) [ 253.544587] ? do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) [ 253.544590] ? entry_SYSCALL_64_after_hwframe (??:?) [ 253.544596] __io_queue_sqe (fs/io_uring.c:?) [ 253.544600] io_queue_sqe (fs/io_uring.c:7143) [ 253.544603] io_submit_sqe (fs/io_uring.c:?) [ 253.544608] io_submit_sqes (fs/io_uring.c:?) [ 253.544612] __se_sys_io_uring_enter (fs/io_uring.c:10154 fs/io_uri ---truncated---

In the Linux kernel, the following vulnerability has been resolved: block: Fix potential deadlock in blk_ia_range_sysfs_show() When being read, a sysfs attribute is already protected against removal with the kobject node active reference counter. As a result, in blk_ia_range_sysfs_show(), there is no need to take the queue sysfs lock when reading the value of a range attribute. Using the queue sysfs lock in this function creates a potential deadlock situation with the disk removal, something that a lockdep signals with a splat when the device is removed: [ 760.703551] Possible unsafe locking scenario: [ 760.703551] [ 760.703554] CPU0 CPU1 [ 760.703556] ---- ---- [ 760.703558] lock(&q->sysfs_lock); [ 760.703565] lock(kn->active#385); [ 760.703573] lock(&q->sysfs_lock); [ 760.703579] lock(kn->active#385); [ 760.703587] [ 760.703587] *** DEADLOCK *** Solve this by removing the mutex_lock()/mutex_unlock() calls from blk_ia_range_sysfs_show().

In the Linux kernel, the following vulnerability has been resolved: ath11k: Fix frames flush failure caused by deadlock We are seeing below warnings: kernel: [25393.301506] ath11k_pci 0000:01:00.0: failed to flush mgmt transmit queue 0 kernel: [25398.421509] ath11k_pci 0000:01:00.0: failed to flush mgmt transmit queue 0 kernel: [25398.421831] ath11k_pci 0000:01:00.0: dropping mgmt frame for vdev 0, is_started 0 this means ath11k fails to flush mgmt. frames because wmi_mgmt_tx_work has no chance to run in 5 seconds. By setting /proc/sys/kernel/hung_task_timeout_secs to 20 and increasing ATH11K_FLUSH_TIMEOUT to 50 we get below warnings: kernel: [ 120.763160] INFO: task wpa_supplicant:924 blocked for more than 20 seconds. kernel: [ 120.763169] Not tainted 5.10.90 #12 kernel: [ 120.763177] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kernel: [ 120.763186] task:wpa_supplicant state:D stack: 0 pid: 924 ppid: 1 flags:0x000043a0 kernel: [ 120.763201] Call Trace: kernel: [ 120.763214] __schedule+0x785/0x12fa kernel: [ 120.763224] ? lockdep_hardirqs_on_prepare+0xe2/0x1bb kernel: [ 120.763242] schedule+0x7e/0xa1 kernel: [ 120.763253] schedule_timeout+0x98/0xfe kernel: [ 120.763266] ? run_local_timers+0x4a/0x4a kernel: [ 120.763291] ath11k_mac_flush_tx_complete+0x197/0x2b1 [ath11k 13c3a9bf37790f4ac8103b3decf7ab4008ac314a] kernel: [ 120.763306] ? init_wait_entry+0x2e/0x2e kernel: [ 120.763343] __ieee80211_flush_queues+0x167/0x21f [mac80211 335da900954f1c5ea7f1613d92088ce83342042c] kernel: [ 120.763378] __ieee80211_recalc_idle+0x105/0x125 [mac80211 335da900954f1c5ea7f1613d92088ce83342042c] kernel: [ 120.763411] ieee80211_recalc_idle+0x14/0x27 [mac80211 335da900954f1c5ea7f1613d92088ce83342042c] kernel: [ 120.763441] ieee80211_free_chanctx+0x77/0xa2 [mac80211 335da900954f1c5ea7f1613d92088ce83342042c] kernel: [ 120.763473] __ieee80211_vif_release_channel+0x100/0x131 [mac80211 335da900954f1c5ea7f1613d92088ce83342042c] kernel: [ 120.763540] ieee80211_vif_release_channel+0x66/0x81 [mac80211 335da900954f1c5ea7f1613d92088ce83342042c] kernel: [ 120.763572] ieee80211_destroy_auth_data+0xa3/0xe6 [mac80211 335da900954f1c5ea7f1613d92088ce83342042c] kernel: [ 120.763612] ieee80211_mgd_deauth+0x178/0x29b [mac80211 335da900954f1c5ea7f1613d92088ce83342042c] kernel: [ 120.763654] cfg80211_mlme_deauth+0x1a8/0x22c [cfg80211 8945aa5bc2af5f6972336665d8ad6f9c191ad5be] kernel: [ 120.763697] nl80211_deauthenticate+0xfa/0x123 [cfg80211 8945aa5bc2af5f6972336665d8ad6f9c191ad5be] kernel: [ 120.763715] genl_rcv_msg+0x392/0x3c2 kernel: [ 120.763750] ? nl80211_associate+0x432/0x432 [cfg80211 8945aa5bc2af5f6972336665d8ad6f9c191ad5be] kernel: [ 120.763782] ? nl80211_associate+0x432/0x432 [cfg80211 8945aa5bc2af5f6972336665d8ad6f9c191ad5be] kernel: [ 120.763802] ? genl_rcv+0x36/0x36 kernel: [ 120.763814] netlink_rcv_skb+0x89/0xf7 kernel: [ 120.763829] genl_rcv+0x28/0x36 kernel: [ 120.763840] netlink_unicast+0x179/0x24b kernel: [ 120.763854] netlink_sendmsg+0x393/0x401 kernel: [ 120.763872] sock_sendmsg+0x72/0x76 kernel: [ 120.763886] ____sys_sendmsg+0x170/0x1e6 kernel: [ 120.763897] ? copy_msghdr_from_user+0x7a/0xa2 kernel: [ 120.763914] ___sys_sendmsg+0x95/0xd1 kernel: [ 120.763940] __sys_sendmsg+0x85/0xbf kernel: [ 120.763956] do_syscall_64+0x43/0x55 kernel: [ 120.763966] entry_SYSCALL_64_after_hwframe+0x44/0xa9 kernel: [ 120.763977] RIP: 0033:0x79089f3fcc83 kernel: [ 120.763986] RSP: 002b:00007ffe604f0508 EFLAGS: 00000246 ORIG_RAX: 000000000000002e kernel: [ 120.763997] RAX: ffffffffffffffda RBX: 000059b40e987690 RCX: 000079089f3fcc83 kernel: [ 120.764006] RDX: 0000000000000000 RSI: 00007ffe604f0558 RDI: 0000000000000009 kernel: [ 120.764014] RBP: 00007ffe604f0540 R08: 0000000000000004 R09: 0000000000400000 kernel: [ 120.764023] R10: 00007ffe604f0638 R11: 0000000000000246 R12: 000059b40ea04980 kernel: [ 120.764032] R13: 00007ffe604 ---truncated---

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: 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: tracing: Fix sleeping function called from invalid context on RT kernel When setting bootparams="trace_event=initcall:initcall_start tp_printk=1" in the cmdline, the output_printk() was called, and the spin_lock_irqsave() was called in the atomic and irq disable interrupt context suitation. On the PREEMPT_RT kernel, these locks are replaced with sleepable rt-spinlock, so the stack calltrace will be triggered. Fix it by raw_spin_lock_irqsave when PREEMPT_RT and "trace_event=initcall:initcall_start tp_printk=1" enabled. BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper/0 preempt_count: 2, expected: 0 RCU nest depth: 0, expected: 0 Preemption disabled at: [<ffffffff8992303e>] try_to_wake_up+0x7e/0xba0 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.17.1-rt17+ #19 34c5812404187a875f32bee7977f7367f9679ea7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x60/0x8c dump_stack+0x10/0x12 __might_resched.cold+0x11d/0x155 rt_spin_lock+0x40/0x70 trace_event_buffer_commit+0x2fa/0x4c0 ? map_vsyscall+0x93/0x93 trace_event_raw_event_initcall_start+0xbe/0x110 ? perf_trace_initcall_finish+0x210/0x210 ? probe_sched_wakeup+0x34/0x40 ? ttwu_do_wakeup+0xda/0x310 ? trace_hardirqs_on+0x35/0x170 ? map_vsyscall+0x93/0x93 do_one_initcall+0x217/0x3c0 ? trace_event_raw_event_initcall_level+0x170/0x170 ? push_cpu_stop+0x400/0x400 ? cblist_init_generic+0x241/0x290 kernel_init_freeable+0x1ac/0x347 ? _raw_spin_unlock_irq+0x65/0x80 ? rest_init+0xf0/0xf0 kernel_init+0x1e/0x150 ret_from_fork+0x22/0x30 </TASK>

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: fscache: Fix oops due to race with cookie_lru and use_cookie If a cookie expires from the LRU and the LRU_DISCARD flag is set, but the state machine has not run yet, it's possible another thread can call fscache_use_cookie and begin to use it. When the cookie_worker finally runs, it will see the LRU_DISCARD flag set, transition the cookie->state to LRU_DISCARDING, which will then withdraw the cookie. Once the cookie is withdrawn the object is removed the below oops will occur because the object associated with the cookie is now NULL. Fix the oops by clearing the LRU_DISCARD bit if another thread uses the cookie before the cookie_worker runs. BUG: kernel NULL pointer dereference, address: 0000000000000008 ... CPU: 31 PID: 44773 Comm: kworker/u130:1 Tainted: G E 6.0.0-5.dneg.x86_64 #1 Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 Workqueue: events_unbound netfs_rreq_write_to_cache_work [netfs] RIP: 0010:cachefiles_prepare_write+0x28/0x90 [cachefiles] ... Call Trace: netfs_rreq_write_to_cache_work+0x11c/0x320 [netfs] process_one_work+0x217/0x3e0 worker_thread+0x4a/0x3b0 kthread+0xd6/0x100

In the Linux kernel, the following vulnerability has been resolved: xsk: Fix race at socket teardown Fix a race in the xsk socket teardown code that can lead to a NULL pointer dereference splat. The current xsk unbind code in xsk_unbind_dev() starts by setting xs->state to XSK_UNBOUND, sets xs->dev to NULL and then waits for any NAPI processing to terminate using synchronize_net(). After that, the release code starts to tear down the socket state and free allocated memory. BUG: kernel NULL pointer dereference, address: 00000000000000c0 PGD 8000000932469067 P4D 8000000932469067 PUD 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 25 PID: 69132 Comm: grpcpp_sync_ser Tainted: G I 5.16.0+ #2 Hardware name: Dell Inc. PowerEdge R730/0599V5, BIOS 1.2.10 03/09/2015 RIP: 0010:__xsk_sendmsg+0x2c/0x690 [...] RSP: 0018:ffffa2348bd13d50 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000040 RCX: ffff8d5fc632d258 RDX: 0000000000400000 RSI: ffffa2348bd13e10 RDI: ffff8d5fc5489800 RBP: ffffa2348bd13db0 R08: 0000000000000000 R09: 00007ffffffff000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8d5fc5489800 R13: ffff8d5fcb0f5140 R14: ffff8d5fcb0f5140 R15: 0000000000000000 FS: 00007f991cff9400(0000) GS:ffff8d6f1f700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000000c0 CR3: 0000000114888005 CR4: 00000000001706e0 Call Trace: <TASK> ? aa_sk_perm+0x43/0x1b0 xsk_sendmsg+0xf0/0x110 sock_sendmsg+0x65/0x70 __sys_sendto+0x113/0x190 ? debug_smp_processor_id+0x17/0x20 ? fpregs_assert_state_consistent+0x23/0x50 ? exit_to_user_mode_prepare+0xa5/0x1d0 __x64_sys_sendto+0x29/0x30 do_syscall_64+0x3b/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xae There are two problems with the current code. First, setting xs->dev to NULL before waiting for all users to stop using the socket is not correct. The entry to the data plane functions xsk_poll(), xsk_sendmsg(), and xsk_recvmsg() are all guarded by a test that xs->state is in the state XSK_BOUND and if not, it returns right away. But one process might have passed this test but still have not gotten to the point in which it uses xs->dev in the code. In this interim, a second process executing xsk_unbind_dev() might have set xs->dev to NULL which will lead to a crash for the first process. The solution here is just to get rid of this NULL assignment since it is not used anymore. Before commit 42fddcc7c64b ("xsk: use state member for socket synchronization"), xs->dev was the gatekeeper to admit processes into the data plane functions, but it was replaced with the state variable xs->state in the aforementioned commit. The second problem is that synchronize_net() does not wait for any process in xsk_poll(), xsk_sendmsg(), or xsk_recvmsg() to complete, which means that the state they rely on might be cleaned up prematurely. This can happen when the notifier gets called (at driver unload for example) as it uses xsk_unbind_dev(). Solve this by extending the RCU critical region from just the ndo_xsk_wakeup to the whole functions mentioned above, so that both the test of xs->state == XSK_BOUND and the last use of any member of xs is covered by the RCU critical section. This will guarantee that when synchronize_net() completes, there will be no processes left executing xsk_poll(), xsk_sendmsg(), or xsk_recvmsg() and state can be cleaned up safely. Note that we need to drop the RCU lock for the skb xmit path as it uses functions that might sleep. Due to this, we have to retest the xs->state after we grab the mutex that protects the skb xmit code from, among a number of things, an xsk_unbind_dev() being executed from the notifier at the same time.

In the Linux kernel, the following vulnerability has been resolved: RDMA/ib_srp: Fix a deadlock Remove the flush_workqueue(system_long_wq) call since flushing system_long_wq is deadlock-prone and since that call is redundant with a preceding cancel_work_sync()

In the Linux kernel, the following vulnerability has been resolved: cfg80211: fix race in netlink owner interface destruction My previous fix here to fix the deadlock left a race where the exact same deadlock (see the original commit referenced below) can still happen if cfg80211_destroy_ifaces() already runs while nl80211_netlink_notify() is still marking some interfaces as nl_owner_dead. The race happens because we have two loops here - first we dev_close() all the netdevs, and then we destroy them. If we also have two netdevs (first one need only be a wdev though) then we can find one during the first iteration, close it, and go to the second iteration -- but then find two, and try to destroy also the one we didn't close yet. Fix this by only iterating once.

In the Linux kernel, the following vulnerability has been resolved: ip: Fix a data-race around sysctl_ip_autobind_reuse. While reading sysctl_ip_autobind_reuse, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader.

In the Linux kernel, the following vulnerability has been resolved: udp: Fix a data-race around sysctl_udp_l3mdev_accept. While reading sysctl_udp_l3mdev_accept, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader.

Integer overflows were discovered in the functions grub_cmd_initrd and grub_initrd_init in the efilinux component of GRUB2, as shipped in Debian, Red Hat, and Ubuntu (the functionality is not included in GRUB2 upstream), leading to a heap-based buffer overflow. These could be triggered by an extremely large number of arguments to the initrd command on 32-bit architectures, or a crafted filesystem with very large files on any architecture. An attacker could use this to execute arbitrary code and bypass UEFI Secure Boot restrictions. This issue affects GRUB2 version 2.04 and prior versions.