In the Linux kernel, the following vulnerability has been resolved: netfilter: ebtables: fix memory leak when blob is malformed The bug fix was incomplete, it "replaced" crash with a memory leak. The old code had an assignment to "ret" embedded into the conditional, restore this.

In the Linux kernel, the following vulnerability has been resolved: iio: adc: men_z188_adc: Fix a resource leak in an error handling path If iio_device_register() fails, a previous ioremap() is left unbalanced. Update the error handling path and add the missing iounmap() call, as already done in the remove function.

In the Linux kernel, the following vulnerability has been resolved: brcmfmac: pcie: Release firmwares in the brcmf_pcie_setup error path This avoids leaking memory if brcmf_chip_get_raminfo fails. Note that the CLM blob is released in the device remove path.

In the Linux kernel, the following vulnerability has been resolved: net/smc: Forward wakeup to smc socket waitqueue after fallback When we replace TCP with SMC and a fallback occurs, there may be some socket waitqueue entries remaining in smc socket->wq, such as eppoll_entries inserted by userspace applications. After the fallback, data flows over TCP/IP and only clcsocket->wq will be woken up. Applications can't be notified by the entries which were inserted in smc socket->wq before fallback. So we need a mechanism to wake up smc socket->wq at the same time if some entries remaining in it. The current workaround is to transfer the entries from smc socket->wq to clcsock->wq during the fallback. But this may cause a crash like this: general protection fault, probably for non-canonical address 0xdead000000000100: 0000 [#1] PREEMPT SMP PTI CPU: 3 PID: 0 Comm: swapper/3 Kdump: loaded Tainted: G E 5.16.0+ #107 RIP: 0010:__wake_up_common+0x65/0x170 Call Trace: <IRQ> __wake_up_common_lock+0x7a/0xc0 sock_def_readable+0x3c/0x70 tcp_data_queue+0x4a7/0xc40 tcp_rcv_established+0x32f/0x660 ? sk_filter_trim_cap+0xcb/0x2e0 tcp_v4_do_rcv+0x10b/0x260 tcp_v4_rcv+0xd2a/0xde0 ip_protocol_deliver_rcu+0x3b/0x1d0 ip_local_deliver_finish+0x54/0x60 ip_local_deliver+0x6a/0x110 ? tcp_v4_early_demux+0xa2/0x140 ? tcp_v4_early_demux+0x10d/0x140 ip_sublist_rcv_finish+0x49/0x60 ip_sublist_rcv+0x19d/0x230 ip_list_rcv+0x13e/0x170 __netif_receive_skb_list_core+0x1c2/0x240 netif_receive_skb_list_internal+0x1e6/0x320 napi_complete_done+0x11d/0x190 mlx5e_napi_poll+0x163/0x6b0 [mlx5_core] __napi_poll+0x3c/0x1b0 net_rx_action+0x27c/0x300 __do_softirq+0x114/0x2d2 irq_exit_rcu+0xb4/0xe0 common_interrupt+0xba/0xe0 </IRQ> <TASK> The crash is caused by privately transferring waitqueue entries from smc socket->wq to clcsock->wq. The owners of these entries, such as epoll, have no idea that the entries have been transferred to a different socket wait queue and still use original waitqueue spinlock (smc socket->wq.wait.lock) to make the entries operation exclusive, but it doesn't work. The operations to the entries, such as removing from the waitqueue (now is clcsock->wq after fallback), may cause a crash when clcsock waitqueue is being iterated over at the moment. This patch tries to fix this by no longer transferring wait queue entries privately, but introducing own implementations of clcsock's callback functions in fallback situation. The callback functions will forward the wakeup to smc socket->wq if clcsock->wq is actually woken up and smc socket->wq has remaining entries.

In the Linux kernel, the following vulnerability has been resolved: ata: pata_octeon_cf: Fix refcount leak in octeon_cf_probe of_find_device_by_node() takes reference, we should use put_device() to release it when not need anymore. Add missing put_device() to avoid refcount leak.

In the Linux kernel, the following vulnerability has been resolved: afs: Fix server->active leak in afs_put_server The atomic_read was accidentally replaced with atomic_inc_return, which prevents the server from getting cleaned up and causes rmmod to hang with a warning: Can't purge s=00000001

In the Linux kernel, the following vulnerability has been resolved: drm/vmwgfx: Remove rcu locks from user resources User resource lookups used rcu to avoid two extra atomics. Unfortunately the rcu paths were buggy and it was easy to make the driver crash by submitting command buffers from two different threads. Because the lookups never show up in performance profiles replace them with a regular spin lock which fixes the races in accesses to those shared resources. Fixes kernel oops'es in IGT's vmwgfx execution_buffer stress test and seen crashes with apps using shared resources.

In the Linux kernel, the following vulnerability has been resolved: soc: brcmstb: pm-arm: Fix refcount leak and __iomem leak bugs In brcmstb_pm_probe(), there are two kinds of leak bugs: (1) we need to add of_node_put() when for_each__matching_node() breaks (2) we need to add iounmap() for each iomap in fail path

In the Linux kernel, the following vulnerability has been resolved: ASoC: atmel: Fix error handling in sam9x5_wm8731_driver_probe The device_node pointer is returned by of_parse_phandle() with refcount incremented. We should use of_node_put() on it when done. This function only calls of_node_put() in the regular path. And it will cause refcount leak in error path.

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: media: vivid: fix compose size exceed boundary syzkaller found a bug: BUG: unable to handle page fault for address: ffffc9000a3b1000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 100000067 P4D 100000067 PUD 10015f067 PMD 1121ca067 PTE 0 Oops: 0002 [#1] PREEMPT SMP CPU: 0 PID: 23489 Comm: vivid-000-vid-c Not tainted 6.1.0-rc1+ #512 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0010:memcpy_erms+0x6/0x10 [...] Call Trace: <TASK> ? tpg_fill_plane_buffer+0x856/0x15b0 vivid_fillbuff+0x8ac/0x1110 vivid_thread_vid_cap_tick+0x361/0xc90 vivid_thread_vid_cap+0x21a/0x3a0 kthread+0x143/0x180 ret_from_fork+0x1f/0x30 </TASK> This is because we forget to check boundary after adjust compose->height int V4L2_SEL_TGT_CROP case. Add v4l2_rect_map_inside() to fix this problem for this case.

In the Linux kernel, the following vulnerability has been resolved: net: dsa: mv88e6xxx: don't use devres for mdiobus As explained in commits: 74b6d7d13307 ("net: dsa: realtek: register the MDIO bus under devres") 5135e96a3dd2 ("net: dsa: don't allocate the slave_mii_bus using devres") mdiobus_free() will panic when called from devm_mdiobus_free() <- devres_release_all() <- __device_release_driver(), and that mdiobus was not previously unregistered. The mv88e6xxx is an MDIO device, so the initial set of constraints that I thought would cause this (I2C or SPI buses which call ->remove on ->shutdown) do not apply. But there is one more which applies here. If the DSA master itself is on a bus that calls ->remove from ->shutdown (like dpaa2-eth, which is on the fsl-mc bus), there is a device link between the switch and the DSA master, and device_links_unbind_consumers() will unbind the Marvell switch driver on shutdown. systemd-shutdown[1]: Powering off. mv88e6085 0x0000000008b96000:00 sw_gl0: Link is Down fsl-mc dpbp.9: Removing from iommu group 7 fsl-mc dpbp.8: Removing from iommu group 7 ------------[ cut here ]------------ kernel BUG at drivers/net/phy/mdio_bus.c:677! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 1 Comm: systemd-shutdow Not tainted 5.16.5-00040-gdc05f73788e5 #15 pc : mdiobus_free+0x44/0x50 lr : devm_mdiobus_free+0x10/0x20 Call trace: mdiobus_free+0x44/0x50 devm_mdiobus_free+0x10/0x20 devres_release_all+0xa0/0x100 __device_release_driver+0x190/0x220 device_release_driver_internal+0xac/0xb0 device_links_unbind_consumers+0xd4/0x100 __device_release_driver+0x4c/0x220 device_release_driver_internal+0xac/0xb0 device_links_unbind_consumers+0xd4/0x100 __device_release_driver+0x94/0x220 device_release_driver+0x28/0x40 bus_remove_device+0x118/0x124 device_del+0x174/0x420 fsl_mc_device_remove+0x24/0x40 __fsl_mc_device_remove+0xc/0x20 device_for_each_child+0x58/0xa0 dprc_remove+0x90/0xb0 fsl_mc_driver_remove+0x20/0x5c __device_release_driver+0x21c/0x220 device_release_driver+0x28/0x40 bus_remove_device+0x118/0x124 device_del+0x174/0x420 fsl_mc_bus_remove+0x80/0x100 fsl_mc_bus_shutdown+0xc/0x1c platform_shutdown+0x20/0x30 device_shutdown+0x154/0x330 kernel_power_off+0x34/0x6c __do_sys_reboot+0x15c/0x250 __arm64_sys_reboot+0x20/0x30 invoke_syscall.constprop.0+0x4c/0xe0 do_el0_svc+0x4c/0x150 el0_svc+0x24/0xb0 el0t_64_sync_handler+0xa8/0xb0 el0t_64_sync+0x178/0x17c So the same treatment must be applied to all DSA switch drivers, which is: either use devres for both the mdiobus allocation and registration, or don't use devres at all. The Marvell driver already has a good structure for mdiobus removal, so just plug in mdiobus_free and get rid of devres.

In the Linux kernel, the following vulnerability has been resolved: mt76: fix monitor mode crash with sdio driver mt7921s driver may receive frames with fragment buffers. If there is a CTS packet received in monitor mode, the payload is 10 bytes only and need 6 bytes header padding after RXD buffer. However, only RXD in the first linear buffer, if we pull buffer size RXD-size+6 bytes with skb_pull(), that would trigger "BUG_ON(skb->len < skb->data_len)" in __skb_pull(). To avoid the nonlinear buffer issue, enlarge the RXD size from 128 to 256 to make sure all MCU operation in linear buffer. [ 52.007562] kernel BUG at include/linux/skbuff.h:2313! [ 52.007578] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP [ 52.007987] pc : skb_pull+0x48/0x4c [ 52.008015] lr : mt7921_queue_rx_skb+0x494/0x890 [mt7921_common] [ 52.008361] Call trace: [ 52.008377] skb_pull+0x48/0x4c [ 52.008400] mt76s_net_worker+0x134/0x1b0 [mt76_sdio 35339a92c6eb7d4bbcc806a1d22f56365565135c] [ 52.008431] __mt76_worker_fn+0xe8/0x170 [mt76 ef716597d11a77150bc07e3fdd68eeb0f9b56917] [ 52.008449] kthread+0x148/0x3ac [ 52.008466] ret_from_fork+0x10/0x30

In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7921e: fix crash in chip reset fail In case of drv own fail in reset, we may need to run mac_reset several times. The sequence would trigger system crash as the log below. Because we do not re-enable/schedule "tx_napi" before disable it again, the process would keep waiting for state change in napi_diable(). To avoid the problem and keep status synchronize for each run, goto final resource handling if drv own failed. [ 5857.353423] mt7921e 0000:3b:00.0: driver own failed [ 5858.433427] mt7921e 0000:3b:00.0: Timeout for driver own [ 5859.633430] mt7921e 0000:3b:00.0: driver own failed [ 5859.633444] ------------[ cut here ]------------ [ 5859.633446] WARNING: CPU: 6 at kernel/kthread.c:659 kthread_park+0x11d [ 5859.633717] Workqueue: mt76 mt7921_mac_reset_work [mt7921_common] [ 5859.633728] RIP: 0010:kthread_park+0x11d/0x150 [ 5859.633736] RSP: 0018:ffff8881b676fc68 EFLAGS: 00010202 ...... [ 5859.633766] Call Trace: [ 5859.633768] <TASK> [ 5859.633771] mt7921e_mac_reset+0x176/0x6f0 [mt7921e] [ 5859.633778] mt7921_mac_reset_work+0x184/0x3a0 [mt7921_common] [ 5859.633785] ? mt7921_mac_set_timing+0x520/0x520 [mt7921_common] [ 5859.633794] ? __kasan_check_read+0x11/0x20 [ 5859.633802] process_one_work+0x7ee/0x1320 [ 5859.633810] worker_thread+0x53c/0x1240 [ 5859.633818] kthread+0x2b8/0x370 [ 5859.633824] ? process_one_work+0x1320/0x1320 [ 5859.633828] ? kthread_complete_and_exit+0x30/0x30 [ 5859.633834] ret_from_fork+0x1f/0x30 [ 5859.633842] </TASK>

In the Linux kernel, the following vulnerability has been resolved: mm: fix unexpected zeroed page mapping with zram swap Two processes under CLONE_VM cloning, user process can be corrupted by seeing zeroed page unexpectedly. CPU A CPU B do_swap_page do_swap_page SWP_SYNCHRONOUS_IO path SWP_SYNCHRONOUS_IO path swap_readpage valid data swap_slot_free_notify delete zram entry swap_readpage zeroed(invalid) data pte_lock map the *zero data* to userspace pte_unlock pte_lock if (!pte_same) goto out_nomap; pte_unlock return and next refault will read zeroed data The swap_slot_free_notify is bogus for CLONE_VM case since it doesn't increase the refcount of swap slot at copy_mm so it couldn't catch up whether it's safe or not to discard data from backing device. In the case, only the lock it could rely on to synchronize swap slot freeing is page table lock. Thus, this patch gets rid of the swap_slot_free_notify function. With this patch, CPU A will see correct data. CPU A CPU B do_swap_page do_swap_page SWP_SYNCHRONOUS_IO path SWP_SYNCHRONOUS_IO path swap_readpage original data pte_lock map the original data swap_free swap_range_free bd_disk->fops->swap_slot_free_notify swap_readpage read zeroed data pte_unlock pte_lock if (!pte_same) goto out_nomap; pte_unlock return on next refault will see mapped data by CPU B The concern of the patch would increase memory consumption since it could keep wasted memory with compressed form in zram as well as uncompressed form in address space. However, most of cases of zram uses no readahead and do_swap_page is followed by swap_free so it will free the compressed form from in zram quickly.

In the Linux kernel, the following vulnerability has been resolved: irqchip/gic-v3: Fix GICR_CTLR.RWP polling It turns out that our polling of RWP is totally wrong when checking for it in the redistributors, as we test the *distributor* bit index, whereas it is a different bit number in the RDs... Oopsie boo. This is embarassing. Not only because it is wrong, but also because it took *8 years* to notice the blunder... Just fix the damn thing.

In the Linux kernel, the following vulnerability has been resolved: powerpc/perf: Fix power_pmu_disable to call clear_pmi_irq_pending only if PMI is pending Running selftest with CONFIG_PPC_IRQ_SOFT_MASK_DEBUG enabled in kernel triggered below warning: [ 172.851380] ------------[ cut here ]------------ [ 172.851391] WARNING: CPU: 8 PID: 2901 at arch/powerpc/include/asm/hw_irq.h:246 power_pmu_disable+0x270/0x280 [ 172.851402] Modules linked in: dm_mod bonding nft_ct nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip_set nf_tables rfkill nfnetlink sunrpc xfs libcrc32c pseries_rng xts vmx_crypto uio_pdrv_genirq uio sch_fq_codel ip_tables ext4 mbcache jbd2 sd_mod t10_pi sg ibmvscsi ibmveth scsi_transport_srp fuse [ 172.851442] CPU: 8 PID: 2901 Comm: lost_exception_ Not tainted 5.16.0-rc5-03218-g798527287598 #2 [ 172.851451] NIP: c00000000013d600 LR: c00000000013d5a4 CTR: c00000000013b180 [ 172.851458] REGS: c000000017687860 TRAP: 0700 Not tainted (5.16.0-rc5-03218-g798527287598) [ 172.851465] MSR: 8000000000029033 <SF,EE,ME,IR,DR,RI,LE> CR: 48004884 XER: 20040000 [ 172.851482] CFAR: c00000000013d5b4 IRQMASK: 1 [ 172.851482] GPR00: c00000000013d5a4 c000000017687b00 c000000002a10600 0000000000000004 [ 172.851482] GPR04: 0000000082004000 c0000008ba08f0a8 0000000000000000 00000008b7ed0000 [ 172.851482] GPR08: 00000000446194f6 0000000000008000 c00000000013b118 c000000000d58e68 [ 172.851482] GPR12: c00000000013d390 c00000001ec54a80 0000000000000000 0000000000000000 [ 172.851482] GPR16: 0000000000000000 0000000000000000 c000000015d5c708 c0000000025396d0 [ 172.851482] GPR20: 0000000000000000 0000000000000000 c00000000a3bbf40 0000000000000003 [ 172.851482] GPR24: 0000000000000000 c0000008ba097400 c0000000161e0d00 c00000000a3bb600 [ 172.851482] GPR28: c000000015d5c700 0000000000000001 0000000082384090 c0000008ba0020d8 [ 172.851549] NIP [c00000000013d600] power_pmu_disable+0x270/0x280 [ 172.851557] LR [c00000000013d5a4] power_pmu_disable+0x214/0x280 [ 172.851565] Call Trace: [ 172.851568] [c000000017687b00] [c00000000013d5a4] power_pmu_disable+0x214/0x280 (unreliable) [ 172.851579] [c000000017687b40] [c0000000003403ac] perf_pmu_disable+0x4c/0x60 [ 172.851588] [c000000017687b60] [c0000000003445e4] __perf_event_task_sched_out+0x1d4/0x660 [ 172.851596] [c000000017687c50] [c000000000d1175c] __schedule+0xbcc/0x12a0 [ 172.851602] [c000000017687d60] [c000000000d11ea8] schedule+0x78/0x140 [ 172.851608] [c000000017687d90] [c0000000001a8080] sys_sched_yield+0x20/0x40 [ 172.851615] [c000000017687db0] [c0000000000334dc] system_call_exception+0x18c/0x380 [ 172.851622] [c000000017687e10] [c00000000000c74c] system_call_common+0xec/0x268 The warning indicates that MSR_EE being set(interrupt enabled) when there was an overflown PMC detected. This could happen in power_pmu_disable since it runs under interrupt soft disable condition ( local_irq_save ) and not with interrupts hard disabled. commit 2c9ac51b850d ("powerpc/perf: Fix PMU callbacks to clear pending PMI before resetting an overflown PMC") intended to clear PMI pending bit in Paca when disabling the PMU. It could happen that PMC gets overflown while code is in power_pmu_disable callback function. Hence add a check to see if PMI pending bit is set in Paca before clearing it via clear_pmi_pending.

In the Linux kernel, the following vulnerability has been resolved: dmaengine: idxd: fix device leaks on compat bind and unbind Make sure to drop the reference taken when looking up the idxd device as part of the compat bind and unbind sysfs interface.

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conncount: fix leaked ct in error paths There are some situations where ct might be leaked as error paths are skipping the refcounted check and return immediately. In order to solve it make sure that the check is always called.

An issue was discovered in the Linux kernel 5.10.x before 5.10.155. A use-after-free in io_sqpoll_wait_sq in fs/io_uring.c allows an attacker to crash the kernel, resulting in denial of service. finish_wait can be skipped. An attack can occur in some situations by forking a process and then quickly terminating it. NOTE: later kernel versions, such as the 5.15 longterm series, substantially changed the implementation of io_sqpoll_wait_sq.

In the Linux kernel, the following vulnerability has been resolved: dax: make sure inodes are flushed before destroy cache A bug can be triggered by following command $ modprobe nd_pmem && modprobe -r nd_pmem [ 10.060014] BUG dax_cache (Not tainted): Objects remaining in dax_cache on __kmem_cache_shutdown() [ 10.060938] Slab 0x0000000085b729ac objects=9 used=1 fp=0x000000004f5ae469 flags=0x200000000010200(slab|head|node) [ 10.062433] Call Trace: [ 10.062673] dump_stack_lvl+0x34/0x44 [ 10.062865] slab_err+0x90/0xd0 [ 10.063619] __kmem_cache_shutdown+0x13b/0x2f0 [ 10.063848] kmem_cache_destroy+0x4a/0x110 [ 10.064058] __x64_sys_delete_module+0x265/0x300 This is caused by dax_fs_exit() not flushing inodes before destroy cache. To fix this issue, call rcu_barrier() before destroy cache.

In the Linux kernel, the following vulnerability has been resolved: net: enetc: deny offload of tc-based TSN features on VF interfaces TSN features on the ENETC (taprio, cbs, gate, police) are configured through a mix of command BD ring messages and port registers: enetc_port_rd(), enetc_port_wr(). Port registers are a region of the ENETC memory map which are only accessible from the PCIe Physical Function. They are not accessible from the Virtual Functions. Moreover, attempting to access these registers crashes the kernel: $ echo 1 > /sys/bus/pci/devices/0000\:00\:00.0/sriov_numvfs pci 0000:00:01.0: [1957:ef00] type 00 class 0x020001 fsl_enetc_vf 0000:00:01.0: Adding to iommu group 15 fsl_enetc_vf 0000:00:01.0: enabling device (0000 -> 0002) fsl_enetc_vf 0000:00:01.0 eno0vf0: renamed from eth0 $ tc qdisc replace dev eno0vf0 root taprio num_tc 8 map 0 1 2 3 4 5 6 7 \ queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 base-time 0 \ sched-entry S 0x7f 900000 sched-entry S 0x80 100000 flags 0x2 Unable to handle kernel paging request at virtual address ffff800009551a08 Internal error: Oops: 96000007 [#1] PREEMPT SMP pc : enetc_setup_tc_taprio+0x170/0x47c lr : enetc_setup_tc_taprio+0x16c/0x47c Call trace: enetc_setup_tc_taprio+0x170/0x47c enetc_setup_tc+0x38/0x2dc taprio_change+0x43c/0x970 taprio_init+0x188/0x1e0 qdisc_create+0x114/0x470 tc_modify_qdisc+0x1fc/0x6c0 rtnetlink_rcv_msg+0x12c/0x390 Split enetc_setup_tc() into separate functions for the PF and for the VF drivers. Also remove enetc_qos.o from being included into enetc-vf.ko, since it serves absolutely no purpose there.

In the Linux kernel, the following vulnerability has been resolved: drm/xe/client: fix deadlock in show_meminfo() There is a real deadlock as well as sleeping in atomic() bug in here, if the bo put happens to be the last ref, since bo destruction wants to grab the same spinlock and sleeping locks. Fix that by dropping the ref using xe_bo_put_deferred(), and moving the final commit outside of the lock. Dropping the lock around the put is tricky since the bo can go out of scope and delete itself from the list, making it difficult to navigate to the next list entry. (cherry picked from commit 0083b8e6f11d7662283a267d4ce7c966812ffd8a)

In the Linux kernel, the following vulnerability has been resolved: mptcp: ensure context reset on disconnect() After the blamed commit below, if the MPC subflow is already in TCP_CLOSE status or has fallback to TCP at mptcp_disconnect() time, mptcp_do_fastclose() skips setting the `send_fastclose flag` and the later __mptcp_close_ssk() does not reset anymore the related subflow context. Any later connection will be created with both the `request_mptcp` flag and the msk-level fallback status off (it is unconditionally cleared at MPTCP disconnect time), leading to a warning in subflow_data_ready(): WARNING: CPU: 26 PID: 8996 at net/mptcp/subflow.c:1519 subflow_data_ready (net/mptcp/subflow.c:1519 (discriminator 13)) Modules linked in: CPU: 26 UID: 0 PID: 8996 Comm: syz.22.39 Not tainted 6.18.0-rc7-05427-g11fc074f6c36 #1 PREEMPT(voluntary) Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 RIP: 0010:subflow_data_ready (net/mptcp/subflow.c:1519 (discriminator 13)) Code: 90 0f 0b 90 90 e9 04 fe ff ff e8 b7 1e f5 fe 89 ee bf 07 00 00 00 e8 db 19 f5 fe 83 fd 07 0f 84 35 ff ff ff e8 9d 1e f5 fe 90 <0f> 0b 90 e9 27 ff ff ff e8 8f 1e f5 fe 4c 89 e7 48 89 de e8 14 09 RSP: 0018:ffffc9002646fb30 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff88813b218000 RCX: ffffffff825c8435 RDX: ffff8881300b3580 RSI: ffffffff825c8443 RDI: 0000000000000005 RBP: 000000000000000b R08: ffffffff825c8435 R09: 000000000000000b R10: 0000000000000005 R11: 0000000000000007 R12: ffff888131ac0000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f88330af6c0(0000) GS:ffff888a93dd2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f88330aefe8 CR3: 000000010ff59000 CR4: 0000000000350ef0 Call Trace: <TASK> tcp_data_ready (net/ipv4/tcp_input.c:5356) tcp_data_queue (net/ipv4/tcp_input.c:5445) tcp_rcv_state_process (net/ipv4/tcp_input.c:7165) tcp_v4_do_rcv (net/ipv4/tcp_ipv4.c:1955) __release_sock (include/net/sock.h:1158 (discriminator 6) net/core/sock.c:3180 (discriminator 6)) release_sock (net/core/sock.c:3737) mptcp_sendmsg (net/mptcp/protocol.c:1763 net/mptcp/protocol.c:1857) inet_sendmsg (net/ipv4/af_inet.c:853 (discriminator 7)) __sys_sendto (net/socket.c:727 (discriminator 15) net/socket.c:742 (discriminator 15) net/socket.c:2244 (discriminator 15)) __x64_sys_sendto (net/socket.c:2247) do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1)) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) RIP: 0033:0x7f883326702d Address the issue setting an explicit `fastclosing` flag at fastclose time, and checking such flag after mptcp_do_fastclose().

In the Linux kernel, the following vulnerability has been resolved: pinctrl: qcom: x1e80100: Fix special pin offsets Remove the erroneus 0x100000 offset to prevent the boards from crashing on pin state setting, as well as for the intended state changes to take effect.

In the Linux kernel, the following vulnerability has been resolved: net: mana: Fix error handling in mana_create_txq/rxq's NAPI cleanup Currently napi_disable() gets called during rxq and txq cleanup, even before napi is enabled and hrtimer is initialized. It causes kernel panic. ? page_fault_oops+0x136/0x2b0 ? page_counter_cancel+0x2e/0x80 ? do_user_addr_fault+0x2f2/0x640 ? refill_obj_stock+0xc4/0x110 ? exc_page_fault+0x71/0x160 ? asm_exc_page_fault+0x27/0x30 ? __mmdrop+0x10/0x180 ? __mmdrop+0xec/0x180 ? hrtimer_active+0xd/0x50 hrtimer_try_to_cancel+0x2c/0xf0 hrtimer_cancel+0x15/0x30 napi_disable+0x65/0x90 mana_destroy_rxq+0x4c/0x2f0 mana_create_rxq.isra.0+0x56c/0x6d0 ? mana_uncfg_vport+0x50/0x50 mana_alloc_queues+0x21b/0x320 ? skb_dequeue+0x5f/0x80

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Check index for aux_rd_interval before using aux_rd_interval has size of 7 and should be checked. This fixes 3 OVERRUN and 1 INTEGER_OVERFLOW issues reported by Coverity.

In the Linux kernel, the following vulnerability has been resolved: nilfs2: protect references to superblock parameters exposed in sysfs The superblock buffers of nilfs2 can not only be overwritten at runtime for modifications/repairs, but they are also regularly swapped, replaced during resizing, and even abandoned when degrading to one side due to backing device issues. So, accessing them requires mutual exclusion using the reader/writer semaphore "nilfs->ns_sem". Some sysfs attribute show methods read this superblock buffer without the necessary mutual exclusion, which can cause problems with pointer dereferencing and memory access, so fix it.

In the Linux kernel, the following vulnerability has been resolved: dma-debug: fix a possible deadlock on radix_lock radix_lock() shouldn't be held while holding dma_hash_entry[idx].lock otherwise, there's a possible deadlock scenario when dma debug API is called holding rq_lock(): CPU0 CPU1 CPU2 dma_free_attrs() check_unmap() add_dma_entry() __schedule() //out (A) rq_lock() get_hash_bucket() (A) dma_entry_hash check_sync() (A) radix_lock() (W) dma_entry_hash dma_entry_free() (W) radix_lock() // CPU2's one (W) rq_lock() CPU1 situation can happen when it extending radix tree and it tries to wake up kswapd via wake_all_kswapd(). CPU2 situation can happen while perf_event_task_sched_out() (i.e. dma sync operation is called while deleting perf_event using etm and etr tmc which are Arm Coresight hwtracing driver backends). To remove this possible situation, call dma_entry_free() after put_hash_bucket() in check_unmap().

In the Linux kernel, the following vulnerability has been resolved: btrfs: clean up our handling of refs == 0 in snapshot delete In reada we BUG_ON(refs == 0), which could be unkind since we aren't holding a lock on the extent leaf and thus could get a transient incorrect answer. In walk_down_proc we also BUG_ON(refs == 0), which could happen if we have extent tree corruption. Change that to return -EUCLEAN. In do_walk_down() we catch this case and handle it correctly, however we return -EIO, which -EUCLEAN is a more appropriate error code. Finally in walk_up_proc we have the same BUG_ON(refs == 0), so convert that to proper error handling. Also adjust the error message so we can actually do something with the information.

In the Linux kernel, the following vulnerability has been resolved: MIPS: cevt-r4k: Don't call get_c0_compare_int if timer irq is installed This avoids warning: [ 0.118053] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:283 Caused by get_c0_compare_int on secondary CPU. We also skipped saving IRQ number to struct clock_event_device *cd as it's never used by clockevent core, as per comments it's only meant for "non CPU local devices".

In the Linux kernel, the following vulnerability has been resolved: ksmbd: Fix memory leak in get_file_all_info() In get_file_all_info(), if vfs_getattr() fails, the function returns immediately without freeing the allocated filename, leading to a memory leak. Fix this by freeing the filename before returning in this error case.

In the Linux kernel, the following vulnerability has been resolved: net: mana: Fix RX buf alloc_size alignment and atomic op panic The MANA driver's RX buffer alloc_size is passed into napi_build_skb() to create SKB. skb_shinfo(skb) is located at the end of skb, and its alignment is affected by the alloc_size passed into napi_build_skb(). The size needs to be aligned properly for better performance and atomic operations. Otherwise, on ARM64 CPU, for certain MTU settings like 4000, atomic operations may panic on the skb_shinfo(skb)->dataref due to alignment fault. To fix this bug, add proper alignment to the alloc_size calculation. Sample panic info: [ 253.298819] Unable to handle kernel paging request at virtual address ffff000129ba5cce [ 253.300900] Mem abort info: [ 253.301760] ESR = 0x0000000096000021 [ 253.302825] EC = 0x25: DABT (current EL), IL = 32 bits [ 253.304268] SET = 0, FnV = 0 [ 253.305172] EA = 0, S1PTW = 0 [ 253.306103] FSC = 0x21: alignment fault Call trace: __skb_clone+0xfc/0x198 skb_clone+0x78/0xe0 raw6_local_deliver+0xfc/0x228 ip6_protocol_deliver_rcu+0x80/0x500 ip6_input_finish+0x48/0x80 ip6_input+0x48/0xc0 ip6_sublist_rcv_finish+0x50/0x78 ip6_sublist_rcv+0x1cc/0x2b8 ipv6_list_rcv+0x100/0x150 __netif_receive_skb_list_core+0x180/0x220 netif_receive_skb_list_internal+0x198/0x2a8 __napi_poll+0x138/0x250 net_rx_action+0x148/0x330 handle_softirqs+0x12c/0x3a0

In the Linux kernel, the following vulnerability has been resolved: char: xillybus: Don't destroy workqueue from work item running on it Triggered by a kref decrement, destroy_workqueue() may be called from within a work item for destroying its own workqueue. This illegal situation is averted by adding a module-global workqueue for exclusive use of the offending work item. Other work items continue to be queued on per-device workqueues to ensure performance.

In the Linux kernel, the following vulnerability has been resolved: genirq/irqdesc: Prevent use-after-free in irq_find_at_or_after() irq_find_at_or_after() dereferences the interrupt descriptor which is returned by mt_find() while neither holding sparse_irq_lock nor RCU read lock, which means the descriptor can be freed between mt_find() and the dereference: CPU0 CPU1 desc = mt_find() delayed_free_desc(desc) irq_desc_get_irq(desc) The use-after-free is reported by KASAN: Call trace: irq_get_next_irq+0x58/0x84 show_stat+0x638/0x824 seq_read_iter+0x158/0x4ec proc_reg_read_iter+0x94/0x12c vfs_read+0x1e0/0x2c8 Freed by task 4471: slab_free_freelist_hook+0x174/0x1e0 __kmem_cache_free+0xa4/0x1dc kfree+0x64/0x128 irq_kobj_release+0x28/0x3c kobject_put+0xcc/0x1e0 delayed_free_desc+0x14/0x2c rcu_do_batch+0x214/0x720 Guard the access with a RCU read lock section.

In the Linux kernel, the following vulnerability has been resolved: scsi: mpi3mr: Avoid memcpy field-spanning write WARNING When the "storcli2 show" command is executed for eHBA-9600, mpi3mr driver prints this WARNING message: memcpy: detected field-spanning write (size 128) of single field "bsg_reply_buf->reply_buf" at drivers/scsi/mpi3mr/mpi3mr_app.c:1658 (size 1) WARNING: CPU: 0 PID: 12760 at drivers/scsi/mpi3mr/mpi3mr_app.c:1658 mpi3mr_bsg_request+0x6b12/0x7f10 [mpi3mr] The cause of the WARN is 128 bytes memcpy to the 1 byte size array "__u8 replay_buf[1]" in the struct mpi3mr_bsg_in_reply_buf. The array is intended to be a flexible length array, so the WARN is a false positive. To suppress the WARN, remove the constant number '1' from the array declaration and clarify that it has flexible length. Also, adjust the memory allocation size to match the change.

In the Linux kernel, the following vulnerability has been resolved: net: relax socket state check at accept time. Christoph reported the following splat: WARNING: CPU: 1 PID: 772 at net/ipv4/af_inet.c:761 __inet_accept+0x1f4/0x4a0 Modules linked in: CPU: 1 PID: 772 Comm: syz-executor510 Not tainted 6.9.0-rc7-g7da7119fe22b #56 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014 RIP: 0010:__inet_accept+0x1f4/0x4a0 net/ipv4/af_inet.c:759 Code: 04 38 84 c0 0f 85 87 00 00 00 41 c7 04 24 03 00 00 00 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc e8 ec b7 da fd <0f> 0b e9 7f fe ff ff e8 e0 b7 da fd 0f 0b e9 fe fe ff ff 89 d9 80 RSP: 0018:ffffc90000c2fc58 EFLAGS: 00010293 RAX: ffffffff836bdd14 RBX: 0000000000000000 RCX: ffff888104668000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: dffffc0000000000 R08: ffffffff836bdb89 R09: fffff52000185f64 R10: dffffc0000000000 R11: fffff52000185f64 R12: dffffc0000000000 R13: 1ffff92000185f98 R14: ffff88810754d880 R15: ffff8881007b7800 FS: 000000001c772880(0000) GS:ffff88811b280000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb9fcf2e178 CR3: 00000001045d2002 CR4: 0000000000770ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <TASK> inet_accept+0x138/0x1d0 net/ipv4/af_inet.c:786 do_accept+0x435/0x620 net/socket.c:1929 __sys_accept4_file net/socket.c:1969 [inline] __sys_accept4+0x9b/0x110 net/socket.c:1999 __do_sys_accept net/socket.c:2016 [inline] __se_sys_accept net/socket.c:2013 [inline] __x64_sys_accept+0x7d/0x90 net/socket.c:2013 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x58/0x100 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x4315f9 Code: fd ff 48 81 c4 80 00 00 00 e9 f1 fe ff ff 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 ab b4 fd ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffdb26d9c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002b RAX: ffffffffffffffda RBX: 0000000000400300 RCX: 00000000004315f9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 00000000006e1018 R08: 0000000000400300 R09: 0000000000400300 R10: 0000000000400300 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000040cdf0 R14: 000000000040ce80 R15: 0000000000000055 </TASK> The reproducer invokes shutdown() before entering the listener status. After commit 94062790aedb ("tcp: defer shutdown(SEND_SHUTDOWN) for TCP_SYN_RECV sockets"), the above causes the child to reach the accept syscall in FIN_WAIT1 status. Eric noted we can relax the existing assertion in __inet_accept()

In the Linux kernel, the following vulnerability has been resolved: Revert "media: v4l2-ctrls: show all owned controls in log_status" This reverts commit 9801b5b28c6929139d6fceeee8d739cc67bb2739. This patch introduced a potential deadlock scenario: [Wed May 8 10:02:06 2024] Possible unsafe locking scenario: [Wed May 8 10:02:06 2024] CPU0 CPU1 [Wed May 8 10:02:06 2024] ---- ---- [Wed May 8 10:02:06 2024] lock(vivid_ctrls:1620:(hdl_vid_cap)->_lock); [Wed May 8 10:02:06 2024] lock(vivid_ctrls:1608:(hdl_user_vid)->_lock); [Wed May 8 10:02:06 2024] lock(vivid_ctrls:1620:(hdl_vid_cap)->_lock); [Wed May 8 10:02:06 2024] lock(vivid_ctrls:1608:(hdl_user_vid)->_lock); For now just revert.

In the Linux kernel, the following vulnerability has been resolved: wifi: iwlwifi: Use request_module_nowait This appears to work around a deadlock regression that came in with the LED merge in 6.9. The deadlock happens on my system with 24 iwlwifi radios, so maybe it something like all worker threads are busy and some work that needs to complete cannot complete. [also remove unnecessary "load_module" var and now-wrong comment]

In the Linux kernel, the following vulnerability has been resolved: ublk: fix deadlock when reading partition table When one process(such as udev) opens ublk block device (e.g., to read the partition table via bdev_open()), a deadlock[1] can occur: 1. bdev_open() grabs disk->open_mutex 2. The process issues read I/O to ublk backend to read partition table 3. In __ublk_complete_rq(), blk_update_request() or blk_mq_end_request() runs bio->bi_end_io() callbacks 4. If this triggers fput() on file descriptor of ublk block device, the work may be deferred to current task's task work (see fput() implementation) 5. This eventually calls blkdev_release() from the same context 6. blkdev_release() tries to grab disk->open_mutex again 7. Deadlock: same task waiting for a mutex it already holds The fix is to run blk_update_request() and blk_mq_end_request() with bottom halves disabled. This forces blkdev_release() to run in kernel work-queue context instead of current task work context, and allows ublk server to make forward progress, and avoids the deadlock. [axboe: rewrite comment in ublk]

In the Linux kernel, the following vulnerability has been resolved: net/smc: fix neighbour and rtable leak in smc_ib_find_route() In smc_ib_find_route(), the neighbour found by neigh_lookup() and rtable resolved by ip_route_output_flow() are not released or put before return. It may cause the refcount leak, so fix it.

In the Linux kernel, the following vulnerability has been resolved: mm: gup: stop abusing try_grab_folio A kernel warning was reported when pinning folio in CMA memory when launching SEV virtual machine. The splat looks like: [ 464.325306] WARNING: CPU: 13 PID: 6734 at mm/gup.c:1313 __get_user_pages+0x423/0x520 [ 464.325464] CPU: 13 PID: 6734 Comm: qemu-kvm Kdump: loaded Not tainted 6.6.33+ #6 [ 464.325477] RIP: 0010:__get_user_pages+0x423/0x520 [ 464.325515] Call Trace: [ 464.325520] <TASK> [ 464.325523] ? __get_user_pages+0x423/0x520 [ 464.325528] ? __warn+0x81/0x130 [ 464.325536] ? __get_user_pages+0x423/0x520 [ 464.325541] ? report_bug+0x171/0x1a0 [ 464.325549] ? handle_bug+0x3c/0x70 [ 464.325554] ? exc_invalid_op+0x17/0x70 [ 464.325558] ? asm_exc_invalid_op+0x1a/0x20 [ 464.325567] ? __get_user_pages+0x423/0x520 [ 464.325575] __gup_longterm_locked+0x212/0x7a0 [ 464.325583] internal_get_user_pages_fast+0xfb/0x190 [ 464.325590] pin_user_pages_fast+0x47/0x60 [ 464.325598] sev_pin_memory+0xca/0x170 [kvm_amd] [ 464.325616] sev_mem_enc_register_region+0x81/0x130 [kvm_amd] Per the analysis done by yangge, when starting the SEV virtual machine, it will call pin_user_pages_fast(..., FOLL_LONGTERM, ...) to pin the memory. But the page is in CMA area, so fast GUP will fail then fallback to the slow path due to the longterm pinnalbe check in try_grab_folio(). The slow path will try to pin the pages then migrate them out of CMA area. But the slow path also uses try_grab_folio() to pin the page, it will also fail due to the same check then the above warning is triggered. In addition, the try_grab_folio() is supposed to be used in fast path and it elevates folio refcount by using add ref unless zero. We are guaranteed to have at least one stable reference in slow path, so the simple atomic add could be used. The performance difference should be trivial, but the misuse may be confusing and misleading. Redefined try_grab_folio() to try_grab_folio_fast(), and try_grab_page() to try_grab_folio(), and use them in the proper paths. This solves both the abuse and the kernel warning. The proper naming makes their usecase more clear and should prevent from abusing in the future. peterx said: : The user will see the pin fails, for gpu-slow it further triggers the WARN : right below that failure (as in the original report): : : folio = try_grab_folio(page, page_increm - 1, : foll_flags); : if (WARN_ON_ONCE(!folio)) { <------------------------ here : /* : * Release the 1st page ref if the : * folio is problematic, fail hard. : */ : gup_put_folio(page_folio(page), 1, : foll_flags); : ret = -EFAULT; : goto out; : } [1] https://lore.kernel.org/linux-mm/1719478388-31917-1-git-send-email-yangge1116@126.com/ [shy828301@gmail.com: fix implicit declaration of function try_grab_folio_fast]

In the Linux kernel, the following vulnerability has been resolved: media: tc358743: register v4l2 async device only after successful setup Ensure the device has been setup correctly before registering the v4l2 async device, thus allowing userspace to access.

A race condition in the x86 KVM subsystem in the Linux kernel through 6.1-rc6 allows guest OS users to cause a denial of service (host OS crash or host OS memory corruption) when nested virtualisation and the TDP MMU are enabled.

In the Linux kernel, the following vulnerability has been resolved: drm/nouveau: prime: fix refcount underflow Calling nouveau_bo_ref() on a nouveau_bo without initializing it (and hence the backing ttm_bo) leads to a refcount underflow. Instead of calling nouveau_bo_ref() in the unwind path of drm_gem_object_init(), clean things up manually. (cherry picked from commit 1b93f3e89d03cfc576636e195466a0d728ad8de5)

IBM Financial Transaction Manager for SWIFT Services for Multiplatforms 3.2.4 could allow an authenticated user to lock additional RM authorizations, resulting in a denial of service on displaying or managing these authorizations. IBM X-Force ID: 240034.

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: Forward soft recovery errors to userspace As we discussed before[1], soft recovery should be forwarded to userspace, or we can get into a really bad state where apps will keep submitting hanging command buffers cascading us to a hard reset. 1: https://lore.kernel.org/all/bf23d5ed-9a6b-43e7-84ee-8cbfd0d60f18@froggi.es/ (cherry picked from commit 434967aadbbbe3ad9103cc29e9a327de20fdba01)

In the Linux kernel, the following vulnerability has been resolved: wifi: iwlwifi: read txq->read_ptr under lock If we read txq->read_ptr without lock, we can read the same value twice, then obtain the lock, and reclaim from there to two different places, but crucially reclaim the same entry twice, resulting in the WARN_ONCE() a little later. Fix that by reading txq->read_ptr under lock.

In the Linux kernel, the following vulnerability has been resolved: virtio_net: Fix napi_skb_cache_put warning After the commit bdacf3e34945 ("net: Use nested-BH locking for napi_alloc_cache.") was merged, the following warning began to appear: WARNING: CPU: 5 PID: 1 at net/core/skbuff.c:1451 napi_skb_cache_put+0x82/0x4b0 __warn+0x12f/0x340 napi_skb_cache_put+0x82/0x4b0 napi_skb_cache_put+0x82/0x4b0 report_bug+0x165/0x370 handle_bug+0x3d/0x80 exc_invalid_op+0x1a/0x50 asm_exc_invalid_op+0x1a/0x20 __free_old_xmit+0x1c8/0x510 napi_skb_cache_put+0x82/0x4b0 __free_old_xmit+0x1c8/0x510 __free_old_xmit+0x1c8/0x510 __pfx___free_old_xmit+0x10/0x10 The issue arises because virtio is assuming it's running in NAPI context even when it's not, such as in the netpoll case. To resolve this, modify virtnet_poll_tx() to only set NAPI when budget is available. Same for virtnet_poll_cleantx(), which always assumed that it was in a NAPI context.

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix racy bitfield write in btrfs_clear_space_info_full() From the memory-barriers.txt document regarding memory barrier ordering guarantees: (*) These guarantees do not apply to bitfields, because compilers often generate code to modify these using non-atomic read-modify-write sequences. Do not attempt to use bitfields to synchronize parallel algorithms. (*) Even in cases where bitfields are protected by locks, all fields in a given bitfield must be protected by one lock. If two fields in a given bitfield are protected by different locks, the compiler's non-atomic read-modify-write sequences can cause an update to one field to corrupt the value of an adjacent field. btrfs_space_info has a bitfield sharing an underlying word consisting of the fields full, chunk_alloc, and flush: struct btrfs_space_info { struct btrfs_fs_info * fs_info; /* 0 8 */ struct btrfs_space_info * parent; /* 8 8 */ ... int clamp; /* 172 4 */ unsigned int full:1; /* 176: 0 4 */ unsigned int chunk_alloc:1; /* 176: 1 4 */ unsigned int flush:1; /* 176: 2 4 */ ... Therefore, to be safe from parallel read-modify-writes losing a write to one of the bitfield members protected by a lock, all writes to all the bitfields must use the lock. They almost universally do, except for btrfs_clear_space_info_full() which iterates over the space_infos and writes out found->full = 0 without a lock. Imagine that we have one thread completing a transaction in which we finished deleting a block_group and are thus calling btrfs_clear_space_info_full() while simultaneously the data reclaim ticket infrastructure is running do_async_reclaim_data_space(): T1 T2 btrfs_commit_transaction btrfs_clear_space_info_full data_sinfo->full = 0 READ: full:0, chunk_alloc:0, flush:1 do_async_reclaim_data_space(data_sinfo) spin_lock(&space_info->lock); if(list_empty(tickets)) space_info->flush = 0; READ: full: 0, chunk_alloc:0, flush:1 MOD/WRITE: full: 0, chunk_alloc:0, flush:0 spin_unlock(&space_info->lock); return; MOD/WRITE: full:0, chunk_alloc:0, flush:1 and now data_sinfo->flush is 1 but the reclaim worker has exited. This breaks the invariant that flush is 0 iff there is no work queued or running. Once this invariant is violated, future allocations that go into __reserve_bytes() will add tickets to space_info->tickets but will see space_info->flush is set to 1 and not queue the work. After this, they will block forever on the resulting ticket, as it is now impossible to kick the worker again. I also confirmed by looking at the assembly of the affected kernel that it is doing RMW operations. For example, to set the flush (3rd) bit to 0, the assembly is: andb $0xfb,0x60(%rbx) and similarly for setting the full (1st) bit to 0: andb $0xfe,-0x20(%rax) So I think this is really a bug on practical systems. I have observed a number of systems in this exact state, but am currently unable to reproduce it. Rather than leaving this footgun lying around for the future, take advantage of the fact that there is room in the struct anyway, and that it is already quite large and simply change the three bitfield members to bools. This avoids writes to space_info->full having any effect on ---truncated---