NULL Pointer Dereference

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix sysfs interface lifetime The current nilfs2 sysfs support has issues with the timing of creation and deletion of sysfs entries, potentially leading to null pointer dereferences, use-after-free, and lockdep warnings. Some of the sysfs attributes for nilfs2 per-filesystem instance refer to metadata file "cpfile", "sufile", or "dat", but nilfs_sysfs_create_device_group that creates those attributes is executed before the inodes for these metadata files are loaded, and nilfs_sysfs_delete_device_group which deletes these sysfs entries is called after releasing their metadata file inodes. Therefore, access to some of these sysfs attributes may occur outside of the lifetime of these metadata files, resulting in inode NULL pointer dereferences or use-after-free. In addition, the call to nilfs_sysfs_create_device_group() is made during the locking period of the semaphore "ns_sem" of nilfs object, so the shrinker call caused by the memory allocation for the sysfs entries, may derive lock dependencies "ns_sem" -> (shrinker) -> "locks acquired in nilfs_evict_inode()". Since nilfs2 may acquire "ns_sem" deep in the call stack holding other locks via its error handler __nilfs_error(), this causes lockdep to report circular locking. This is a false positive and no circular locking actually occurs as no inodes exist yet when nilfs_sysfs_create_device_group() is called. Fortunately, the lockdep warnings can be resolved by simply moving the call to nilfs_sysfs_create_device_group() out of "ns_sem". This fixes these sysfs issues by revising where the device's sysfs interface is created/deleted and keeping its lifetime within the lifetime of the metadata files above.Show less

In the Linux kernel, the following vulnerability has been resolved: media: platform: mediatek: vpu: fix NULL ptr dereference If pdev is NULL, then it is still dereferenced. This fixes this smatch warning: drivers/media/platform/mediatek/vpu/mtk_vpu.c:570 vpu_load_firmware() warn: address of NULL pointer 'pdev'Show less

In the Linux kernel, the following vulnerability has been resolved: blk-cgroup: Reinit blkg_iostat_set after clearing in blkcg_reset_stats() When blkg_alloc() is called to allocate a blkcg_gq structure with the associated blkg_iostat_set's, there are 2 fields within blkg_iostat_set that requires proper initialization - blkg & sync. The former field was introduced by commit 3b8cc6298724 ("blk-cgroup: Optimize blkcg_rstat_flush()") while the later one was introduced by commit f73316482977 ("blk-cgroup: reimplement basic IO stats using cgroup rstat"). Unfortunately those fields in the blkg_iostat_set's are not properly re-initialized when they are cleared in v1's blkcg_reset_stats(). This can lead to a kernel panic due to NULL pointer access of the blkg pointer. The missing initialization of sync is less problematic and can be a problem in a debug kernel due to missing lockdep initialization. Fix these problems by re-initializing them after memory clearing.Show less

In the Linux kernel, the following vulnerability has been resolved: rcu: Protect rcu_print_task_exp_stall() ->exp_tasks access For kernels built with CONFIG_PREEMPT_RCU=y, the following scenario can result in a NULL-pointer dereference: CPU1 CPU2 rcu_preempt_deferred_qs_irqrestore rcu_print_task_exp_stall if (special.b.blocked) READ_ONCE(rnp->exp_tasks) != NULL raw_spin_lock_rcu_node np = rcu_next_node_entry(t, rnp) if (&t->rcu_node_entry == rnp->exp_tasks) WRITE_ONCE(rnp->exp_tasks, np) .... raw_spin_unlock_irqrestore_rcu_node raw_spin_lock_irqsave_rcu_node t = list_entry(rnp->exp_tasks->prev, struct task_struct, rcu_node_entry) (if rnp->exp_tasks is NULL, this will dereference a NULL pointer) The problem is that CPU2 accesses the rcu_node structure's->exp_tasks field without holding the rcu_node structure's ->lock and CPU2 did not observe CPU1's change to rcu_node structure's ->exp_tasks in time. Therefore, if CPU1 sets rcu_node structure's->exp_tasks pointer to NULL, then CPU2 might dereference that NULL pointer. This commit therefore holds the rcu_node structure's ->lock while accessing that structure's->exp_tasks field. [ paulmck: Apply Frederic Weisbecker feedback. ]Show less

In the Linux kernel, the following vulnerability has been resolved: parisc: led: Fix potential null-ptr-deref in start_task() start_task() calls create_singlethread_workqueue() and not checked the ret value, which may return NULL. And a null-ptr-deref may happen: start_task() create_singlethread_workqueue() # failed, led_wq is NULL queue_delayed_work() queue_delayed_work_on() __queue_delayed_work() # warning here, but continue __queue_work() # access wq->flags, null-ptr-deref Check the ret value and return -ENOMEM if it is NULL.Show less

In the Linux kernel, the following vulnerability has been resolved: net: If sock is dead don't access sock's sk_wq in sk_stream_wait_memory Fixes the below NULL pointer dereference: [...] [ 14.471200] Call Trace: [ 14.471562] <TASK> [ 14.471882] lock_acquire+0x245/0x2e0 [ 14.472416] ? remove_wait_queue+0x12/0x50 [ 14.473014] ? _raw_spin_lock_irqsave+0x17/0x50 [ 14.473681] _raw_spin_lock_irqsave+0x3d/0x50 [ 14.474318] ? remove_wait_queue+0x12/0x50 [ 14.474907] remove_wait_queue+0x12/0x50 [ 14.475480] sk_stream_wait_memory+0x20d/0x340 [ 14.476127] ? do_wait_intr_irq+0x80/0x80 [ 14.476704] do_tcp_sendpages+0x287/0x600 [ 14.477283] tcp_bpf_push+0xab/0x260 [ 14.477817] tcp_bpf_sendmsg_redir+0x297/0x500 [ 14.478461] ? __local_bh_enable_ip+0x77/0xe0 [ 14.479096] tcp_bpf_send_verdict+0x105/0x470 [ 14.479729] tcp_bpf_sendmsg+0x318/0x4f0 [ 14.480311] sock_sendmsg+0x2d/0x40 [ 14.480822] ____sys_sendmsg+0x1b4/0x1c0 [ 14.481390] ? copy_msghdr_from_user+0x62/0x80 [ 14.482048] ___sys_sendmsg+0x78/0xb0 [ 14.482580] ? vmf_insert_pfn_prot+0x91/0x150 [ 14.483215] ? __do_fault+0x2a/0x1a0 [ 14.483738] ? do_fault+0x15e/0x5d0 [ 14.484246] ? __handle_mm_fault+0x56b/0x1040 [ 14.484874] ? lock_is_held_type+0xdf/0x130 [ 14.485474] ? find_held_lock+0x2d/0x90 [ 14.486046] ? __sys_sendmsg+0x41/0x70 [ 14.486587] __sys_sendmsg+0x41/0x70 [ 14.487105] ? intel_pmu_drain_pebs_core+0x350/0x350 [ 14.487822] do_syscall_64+0x34/0x80 [ 14.488345] entry_SYSCALL_64_after_hwframe+0x63/0xcd [...] The test scenario has the following flow: thread1 thread2 ----------- --------------- tcp_bpf_sendmsg tcp_bpf_send_verdict tcp_bpf_sendmsg_redir sock_close tcp_bpf_push_locked __sock_release tcp_bpf_push //inet_release do_tcp_sendpages sock->ops->release sk_stream_wait_memory // tcp_close sk_wait_event sk->sk_prot->close release_sock(__sk); *** lock_sock(sk); __tcp_close sock_orphan(sk) sk->sk_wq = NULL release_sock **** lock_sock(__sk); remove_wait_queue(sk_sleep(sk), &wait); sk_sleep(sk) //NULL pointer dereference &rcu_dereference_raw(sk->sk_wq)->wait While waiting for memory in thread1, the socket is released with its wait queue because thread2 has closed it. This caused by tcp_bpf_send_verdict didn't increase the f_count of psock->sk_redir->sk_socket->file in thread1. We should check if SOCK_DEAD flag is set on wakeup in sk_stream_wait_memory before accessing the wait queue.Show less

In the Linux kernel, the following vulnerability has been resolved: net/tunnel: wait until all sk_user_data reader finish before releasing the sock There is a race condition in vxlan that when deleting a vxlan device during receiving packets, there is a possibility that the sock is released after getting vxlan_sock vs from sk_user_data. Then in later vxlan_ecn_decapsulate(), vxlan_get_sk_family() we will got NULL pointer dereference. e.g. #0 [ffffa25ec6978a38] machine_kexec at ffffffff8c669757 #1 [ffffa25ec6978a90] __crash_kexec at ffffffff8c7c0a4d #2 [ffffa25ec6978b58] crash_kexec at ffffffff8c7c1c48 #3 [ffffa25ec6978b60] oops_end at ffffffff8c627f2b #4 [ffffa25ec6978b80] page_fault_oops at ffffffff8c678fcb #5 [ffffa25ec6978bd8] exc_page_fault at ffffffff8d109542 #6 [ffffa25ec6978c00] asm_exc_page_fault at ffffffff8d200b62 [exception RIP: vxlan_ecn_decapsulate+0x3b] RIP: ffffffffc1014e7b RSP: ffffa25ec6978cb0 RFLAGS: 00010246 RAX: 0000000000000008 RBX: ffff8aa000888000 RCX: 0000000000000000 RDX: 000000000000000e RSI: ffff8a9fc7ab803e RDI: ffff8a9fd1168700 RBP: ffff8a9fc7ab803e R8: 0000000000700000 R9: 00000000000010ae R10: ffff8a9fcb748980 R11: 0000000000000000 R12: ffff8a9fd1168700 R13: ffff8aa000888000 R14: 00000000002a0000 R15: 00000000000010ae ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 #7 [ffffa25ec6978ce8] vxlan_rcv at ffffffffc10189cd [vxlan] #8 [ffffa25ec6978d90] udp_queue_rcv_one_skb at ffffffff8cfb6507 #9 [ffffa25ec6978dc0] udp_unicast_rcv_skb at ffffffff8cfb6e45 #10 [ffffa25ec6978dc8] __udp4_lib_rcv at ffffffff8cfb8807 #11 [ffffa25ec6978e20] ip_protocol_deliver_rcu at ffffffff8cf76951 #12 [ffffa25ec6978e48] ip_local_deliver at ffffffff8cf76bde #13 [ffffa25ec6978ea0] __netif_receive_skb_one_core at ffffffff8cecde9b #14 [ffffa25ec6978ec8] process_backlog at ffffffff8cece139 #15 [ffffa25ec6978f00] __napi_poll at ffffffff8ceced1a #16 [ffffa25ec6978f28] net_rx_action at ffffffff8cecf1f3 #17 [ffffa25ec6978fa0] __softirqentry_text_start at ffffffff8d4000ca #18 [ffffa25ec6978ff0] do_softirq at ffffffff8c6fbdc3 Reproducer: https://github.com/Mellanox/ovs-tests/blob/master/test-ovs-vxlan-remove-tunnel-during-traffic.sh Fix this by waiting for all sk_user_data reader to finish before releasing the sock.Show less

In the Linux kernel, the following vulnerability has been resolved: drivers/md/md-bitmap: check the return value of md_bitmap_get_counter() Check the return value of md_bitmap_get_counter() in case it returns NULL pointer, which will result in a null pointer dereference. v2: update the check to include other dereferenceShow less

In the Linux kernel, the following vulnerability has been resolved: mm: kmem: fix a NULL pointer dereference in obj_stock_flush_required() KCSAN found an issue in obj_stock_flush_required(): stock->cached_objcg can be reset between the check and dereference: ================================================================== BUG: KCSAN: data-race in drain_all_stock / drain_obj_stock write to 0xffff888237c2a2f8 of 8 bytes by task 19625 on cpu 0: drain_obj_stock+0x408/0x4e0 mm/memcontrol.c:3306 refill_obj_stock+0x9c/0x1e0 mm/memcontrol.c:3340 obj_cgroup_uncharge+0xe/0x10 mm/memcontrol.c:3408 memcg_slab_free_hook mm/slab.h:587 [inline] __cache_free mm/slab.c:3373 [inline] __do_kmem_cache_free mm/slab.c:3577 [inline] kmem_cache_free+0x105/0x280 mm/slab.c:3602 __d_free fs/dcache.c:298 [inline] dentry_free fs/dcache.c:375 [inline] __dentry_kill+0x422/0x4a0 fs/dcache.c:621 dentry_kill+0x8d/0x1e0 dput+0x118/0x1f0 fs/dcache.c:913 __fput+0x3bf/0x570 fs/file_table.c:329 ____fput+0x15/0x20 fs/file_table.c:349 task_work_run+0x123/0x160 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xcf/0xe0 kernel/entry/common.c:171 exit_to_user_mode_prepare+0x6a/0xa0 kernel/entry/common.c:203 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:296 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd read to 0xffff888237c2a2f8 of 8 bytes by task 19632 on cpu 1: obj_stock_flush_required mm/memcontrol.c:3319 [inline] drain_all_stock+0x174/0x2a0 mm/memcontrol.c:2361 try_charge_memcg+0x6d0/0xd10 mm/memcontrol.c:2703 try_charge mm/memcontrol.c:2837 [inline] mem_cgroup_charge_skmem+0x51/0x140 mm/memcontrol.c:7290 sock_reserve_memory+0xb1/0x390 net/core/sock.c:1025 sk_setsockopt+0x800/0x1e70 net/core/sock.c:1525 udp_lib_setsockopt+0x99/0x6c0 net/ipv4/udp.c:2692 udp_setsockopt+0x73/0xa0 net/ipv4/udp.c:2817 sock_common_setsockopt+0x61/0x70 net/core/sock.c:3668 __sys_setsockopt+0x1c3/0x230 net/socket.c:2271 __do_sys_setsockopt net/socket.c:2282 [inline] __se_sys_setsockopt net/socket.c:2279 [inline] __x64_sys_setsockopt+0x66/0x80 net/socket.c:2279 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd value changed: 0xffff8881382d52c0 -> 0xffff888138893740 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 19632 Comm: syz-executor.0 Not tainted 6.3.0-rc2-syzkaller-00387-g534293368afa #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023 Fix it by using READ_ONCE()/WRITE_ONCE() for all accesses to stock->cached_objcg.Show less

In the Linux kernel, the following vulnerability has been resolved: drm/mediatek: dp: Only trigger DRM HPD events if bridge is attached The MediaTek DisplayPort interface bridge driver starts its interrupts as soon as its probed. However when the interrupts trigger the bridge might not have been attached to a DRM device. As drm_helper_hpd_irq_event() does not check whether the passed in drm_device is valid or not, a NULL pointer passed in results in a kernel NULL pointer dereference in it. Check whether the bridge is attached and only trigger an HPD event if it is.Show less

In the Linux kernel, the following vulnerability has been resolved: wifi: mwifiex: avoid possible NULL skb pointer dereference In 'mwifiex_handle_uap_rx_forward()', always check the value returned by 'skb_copy()' to avoid potential NULL pointer dereference in 'mwifiex_uap_queue_bridged_pkt()', and drop original skb in case of copying failure. Found by Linux Verification Center (linuxtesting.org) with SVACE.Show less

In the Linux kernel, the following vulnerability has been resolved: net/smc: Reset connection when trying to use SMCRv2 fails. We found a crash when using SMCRv2 with 2 Mellanox ConnectX-4. It can be reproduced by: - smc_run nginx - smc_run wrk -t 32 -c 500 -d 30 http://<ip>:<port> BUG: kernel NULL pointer dereference, address: 0000000000000014 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 8000000108713067 P4D 8000000108713067 PUD 151127067 PMD 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 4 PID: 2441 Comm: kworker/4:249 Kdump: loaded Tainted: G W E 6.4.0-rc1+ #42 Workqueue: smc_hs_wq smc_listen_work [smc] RIP: 0010:smc_clc_send_confirm_accept+0x284/0x580 [smc] RSP: 0018:ffffb8294b2d7c78 EFLAGS: 00010a06 RAX: ffff8f1873238880 RBX: ffffb8294b2d7dc8 RCX: 0000000000000000 RDX: 00000000000000b4 RSI: 0000000000000001 RDI: 0000000000b40c00 RBP: ffffb8294b2d7db8 R08: ffff8f1815c5860c R09: 0000000000000000 R10: 0000000000000400 R11: 0000000000000000 R12: ffff8f1846f56180 R13: ffff8f1815c5860c R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8f1aefd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000014 CR3: 00000001027a0001 CR4: 00000000003706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ? mlx5_ib_map_mr_sg+0xa1/0xd0 [mlx5_ib] ? smcr_buf_map_link+0x24b/0x290 [smc] ? __smc_buf_create+0x4ee/0x9b0 [smc] smc_clc_send_accept+0x4c/0xb0 [smc] smc_listen_work+0x346/0x650 [smc] ? __schedule+0x279/0x820 process_one_work+0x1e5/0x3f0 worker_thread+0x4d/0x2f0 ? __pfx_worker_thread+0x10/0x10 kthread+0xe5/0x120 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x2c/0x50 </TASK> During the CLC handshake, server sequentially tries available SMCRv2 and SMCRv1 devices in smc_listen_work(). If an SMCRv2 device is found. SMCv2 based link group and link will be assigned to the connection. Then assumed that some buffer assignment errors happen later in the CLC handshake, such as RMB registration failure, server will give up SMCRv2 and try SMCRv1 device instead. But the resources assigned to the connection won't be reset. When server tries SMCRv1 device, the connection creation process will be executed again. Since conn->lnk has been assigned when trying SMCRv2, it will not be set to the correct SMCRv1 link in smcr_lgr_conn_assign_link(). So in such situation, conn->lgr points to correct SMCRv1 link group but conn->lnk points to the SMCRv2 link mistakenly. Then in smc_clc_send_confirm_accept(), conn->rmb_desc->mr[link->link_idx] will be accessed. Since the link->link_idx is not correct, the related MR may not have been initialized, so crash happens. | Try SMCRv2 device first | |-> conn->lgr: assign existed SMCRv2 link group; | |-> conn->link: assign existed SMCRv2 link (link_idx may be 1 in SMC_LGR_SYMMETRIC); | |-> sndbuf & RMB creation fails, quit; | | Try SMCRv1 device then | |-> conn->lgr: create SMCRv1 link group and assign; | |-> conn->link: keep SMCRv2 link mistakenly; | |-> sndbuf & RMB creation succeed, only RMB->mr[link_idx = 0] | initialized. | | Then smc_clc_send_confirm_accept() accesses | conn->rmb_desc->mr[conn->link->link_idx, which is 1], then crash. v This patch tries to fix this by cleaning conn->lnk before assigning link. In addition, it is better to reset the connection and clean the resources assigned if trying SMCRv2 failed in buffer creation or registration.Show less

In the Linux kernel, the following vulnerability has been resolved: md/raid10: fix null-ptr-deref of mreplace in raid10_sync_request There are two check of 'mreplace' in raid10_sync_request(). In the first check, 'need_replace' will be set and 'mreplace' will be used later if no-Faulty 'mreplace' exists, In the second check, 'mreplace' will be set to NULL if it is Faulty, but 'need_replace' will not be changed accordingly. null-ptr-deref occurs if Faulty is set between two check. Fix it by merging two checks into one. And replace 'need_replace' with 'mreplace' because their values are always the same.Show less

In the Linux kernel, the following vulnerability has been resolved: nvme: fix multipath crash caused by flush request when blktrace is enabled The flush request initialized by blk_kick_flush has NULL bio, and it may be dealt with nvme_end_req during io completion. When blktrace is enabled, nvme_trace_bio_complete with multipath activated trying to access NULL pointer bio from flush request results in the following crash: [ 2517.831677] BUG: kernel NULL pointer dereference, address: 000000000000001a [ 2517.835213] #PF: supervisor read access in kernel mode [ 2517.838724] #PF: error_code(0x0000) - not-present page [ 2517.842222] PGD 7b2d51067 P4D 0 [ 2517.845684] Oops: 0000 [#1] SMP NOPTI [ 2517.849125] CPU: 2 PID: 732 Comm: kworker/2:1H Kdump: loaded Tainted: G S 5.15.67-0.cl9.x86_64 #1 [ 2517.852723] Hardware name: XFUSION 2288H V6/BC13MBSBC, BIOS 1.13 07/27/2022 [ 2517.856358] Workqueue: nvme_tcp_wq nvme_tcp_io_work [nvme_tcp] [ 2517.859993] RIP: 0010:blk_add_trace_bio_complete+0x6/0x30 [ 2517.863628] Code: 1f 44 00 00 48 8b 46 08 31 c9 ba 04 00 10 00 48 8b 80 50 03 00 00 48 8b 78 50 e9 e5 fe ff ff 0f 1f 44 00 00 41 54 49 89 f4 55 <0f> b6 7a 1a 48 89 d5 e8 3e 1c 2b 00 48 89 ee 4c 89 e7 5d 89 c1 ba [ 2517.871269] RSP: 0018:ff7f6a008d9dbcd0 EFLAGS: 00010286 [ 2517.875081] RAX: ff3d5b4be00b1d50 RBX: 0000000002040002 RCX: ff3d5b0a270f2000 [ 2517.878966] RDX: 0000000000000000 RSI: ff3d5b0b021fb9f8 RDI: 0000000000000000 [ 2517.882849] RBP: ff3d5b0b96a6fa00 R08: 0000000000000001 R09: 0000000000000000 [ 2517.886718] R10: 000000000000000c R11: 000000000000000c R12: ff3d5b0b021fb9f8 [ 2517.890575] R13: 0000000002000000 R14: ff3d5b0b021fb1b0 R15: 0000000000000018 [ 2517.894434] FS: 0000000000000000(0000) GS:ff3d5b42bfc80000(0000) knlGS:0000000000000000 [ 2517.898299] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 2517.902157] CR2: 000000000000001a CR3: 00000004f023e005 CR4: 0000000000771ee0 [ 2517.906053] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 2517.909930] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 2517.913761] PKRU: 55555554 [ 2517.917558] Call Trace: [ 2517.921294] <TASK> [ 2517.924982] nvme_complete_rq+0x1c3/0x1e0 [nvme_core] [ 2517.928715] nvme_tcp_recv_pdu+0x4d7/0x540 [nvme_tcp] [ 2517.932442] nvme_tcp_recv_skb+0x4f/0x240 [nvme_tcp] [ 2517.936137] ? nvme_tcp_recv_pdu+0x540/0x540 [nvme_tcp] [ 2517.939830] tcp_read_sock+0x9c/0x260 [ 2517.943486] nvme_tcp_try_recv+0x65/0xa0 [nvme_tcp] [ 2517.947173] nvme_tcp_io_work+0x64/0x90 [nvme_tcp] [ 2517.950834] process_one_work+0x1e8/0x390 [ 2517.954473] worker_thread+0x53/0x3c0 [ 2517.958069] ? process_one_work+0x390/0x390 [ 2517.961655] kthread+0x10c/0x130 [ 2517.965211] ? set_kthread_struct+0x40/0x40 [ 2517.968760] ret_from_fork+0x1f/0x30 [ 2517.972285] </TASK> To avoid this situation, add a NULL check for req->bio before calling trace_block_bio_complete.Show less

In the Linux kernel, the following vulnerability has been resolved: media: mediatek: vcodec: Can't set dst buffer to done when lat decode error Core thread will call v4l2_m2m_buf_done to set dst buffer done for lat architecture. If lat call v4l2_m2m_buf_done_and_job_finish to free dst buffer when lat decode error, core thread will access kernel NULL pointer dereference, then crash.Show less

In the Linux kernel, the following vulnerability has been resolved: md: fix a crash in mempool_free There's a crash in mempool_free when running the lvm test shell/lvchange-rebuild-raid.sh. The reason for the crash is this: * super_written calls atomic_dec_and_test(&mddev->pending_writes) and wake_up(&mddev->sb_wait). Then it calls rdev_dec_pending(rdev, mddev) and bio_put(bio). * so, the process that waited on sb_wait and that is woken up is racing with bio_put(bio). * if the process wins the race, it calls bioset_exit before bio_put(bio) is executed. * bio_put(bio) attempts to free a bio into a destroyed bio set - causing a crash in mempool_free. We fix this bug by moving bio_put before atomic_dec_and_test. We also move rdev_dec_pending before atomic_dec_and_test as suggested by Neil Brown. The function md_end_flush has a similar bug - we must call bio_put before we decrement the number of in-progress bios. BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 11557f0067 P4D 11557f0067 PUD 0 Oops: 0002 [#1] PREEMPT SMP CPU: 0 PID: 73 Comm: kworker/0:1 Not tainted 6.1.0-rc3 #5 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Workqueue: kdelayd flush_expired_bios [dm_delay] RIP: 0010:mempool_free+0x47/0x80 Code: 48 89 ef 5b 5d ff e0 f3 c3 48 89 f7 e8 32 45 3f 00 48 63 53 08 48 89 c6 3b 53 04 7d 2d 48 8b 43 10 8d 4a 01 48 89 df 89 4b 08 <48> 89 2c d0 e8 b0 45 3f 00 48 8d 7b 30 5b 5d 31 c9 ba 01 00 00 00 RSP: 0018:ffff88910036bda8 EFLAGS: 00010093 RAX: 0000000000000000 RBX: ffff8891037b65d8 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000202 RDI: ffff8891037b65d8 RBP: ffff8891447ba240 R08: 0000000000012908 R09: 00000000003d0900 R10: 0000000000000000 R11: 0000000000173544 R12: ffff889101a14000 R13: ffff8891562ac300 R14: ffff889102b41440 R15: ffffe8ffffa00d05 FS: 0000000000000000(0000) GS:ffff88942fa00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000001102e99000 CR4: 00000000000006b0 Call Trace: <TASK> clone_endio+0xf4/0x1c0 [dm_mod] clone_endio+0xf4/0x1c0 [dm_mod] __submit_bio+0x76/0x120 submit_bio_noacct_nocheck+0xb6/0x2a0 flush_expired_bios+0x28/0x2f [dm_delay] process_one_work+0x1b4/0x300 worker_thread+0x45/0x3e0 ? rescuer_thread+0x380/0x380 kthread+0xc2/0x100 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x1f/0x30 </TASK> Modules linked in: brd dm_delay dm_raid dm_mod af_packet uvesafb cfbfillrect cfbimgblt cn cfbcopyarea fb font fbdev tun autofs4 binfmt_misc configfs ipv6 virtio_rng virtio_balloon rng_core virtio_net pcspkr net_failover failover qemu_fw_cfg button mousedev raid10 raid456 libcrc32c async_raid6_recov async_memcpy async_pq raid6_pq async_xor xor async_tx raid1 raid0 md_mod sd_mod t10_pi crc64_rocksoft crc64 virtio_scsi scsi_mod evdev psmouse bsg scsi_common [last unloaded: brd] CR2: 0000000000000000 ---[ end trace 0000000000000000 ]---Show less

In the Linux kernel, the following vulnerability has been resolved: mm: /proc/pid/smaps_rollup: fix no vma's null-deref Commit 258f669e7e88 ("mm: /proc/pid/smaps_rollup: convert to single value seq_file") introduced a null-deref if there are no vma's in the task in show_smaps_rollup.Show less

Dragonfly is an open source P2P-based file distribution and image acceleration system. Prior to 2.1.0, the first return value of a function is dereferenced even when the function returns an error. This can result in a nil dereference, and cause code to panic. This vulnerability is fixed in 2.1.0.Show less

In the Linux kernel, the following vulnerability has been resolved: block: be a bit more careful in checking for NULL bdev while polling Wei reports a crash with an application using polled IO: PGD 14265e067 P4D 14265e067 PUD 47ec50067 PMD 0 Oops: 0000 [#1] SMP CPU: 0 PID: 21915 Comm: iocore_0 Kdump: loaded Tainted: G S 5.12.0-0_fbk12_clang_7346_g1bb6f2e7058f #1 Hardware name: Wiwynn Delta Lake MP T8/Delta Lake-Class2, BIOS Y3DLM08 04/10/2022 RIP: 0010:bio_poll+0x25/0x200 Code: 0f 1f 44 00 00 0f 1f 44 00 00 55 41 57 41 56 41 55 41 54 53 48 83 ec 28 65 48 8b 04 25 28 00 00 00 48 89 44 24 20 48 8b 47 08 <48> 8b 80 70 02 00 00 4c 8b 70 50 8b 6f 34 31 db 83 fd ff 75 25 65 RSP: 0018:ffffc90005fafdf8 EFLAGS: 00010292 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 74b43cd65dd66600 RDX: 0000000000000003 RSI: ffffc90005fafe78 RDI: ffff8884b614e140 RBP: ffff88849964df78 R08: 0000000000000000 R09: 0000000000000008 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88849964df00 R13: ffffc90005fafe78 R14: ffff888137d3c378 R15: 0000000000000001 FS: 00007fd195000640(0000) GS:ffff88903f400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000270 CR3: 0000000466121001 CR4: 00000000007706f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: iocb_bio_iopoll+0x1d/0x30 io_do_iopoll+0xac/0x250 __se_sys_io_uring_enter+0x3c5/0x5a0 ? __x64_sys_write+0x89/0xd0 do_syscall_64+0x2d/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x94f225d Code: 24 cc 00 00 00 41 8b 84 24 d0 00 00 00 c1 e0 04 83 e0 10 41 09 c2 8b 33 8b 53 04 4c 8b 43 18 4c 63 4b 0c b8 aa 01 00 00 0f 05 <85> c0 0f 88 85 00 00 00 29 03 45 84 f6 0f 84 88 00 00 00 41 f6 c7 RSP: 002b:00007fd194ffcd88 EFLAGS: 00000202 ORIG_RAX: 00000000000001aa RAX: ffffffffffffffda RBX: 00007fd194ffcdc0 RCX: 00000000094f225d RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000007 RBP: 00007fd194ffcdb0 R08: 0000000000000000 R09: 0000000000000008 R10: 0000000000000001 R11: 0000000000000202 R12: 00007fd269d68030 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000 which is due to bio->bi_bdev being NULL. This can happen if we have two tasks doing polled IO, and task B ends up completing IO from task A if they are sharing a poll queue. If task B completes the IO and puts the bio into our cache, then it can allocate that bio again before task A is done polling for it. As that would necessitate a preempt between the two tasks, it's enough to just be a bit more careful in checking for whether or not bio->bi_bdev is NULL.Show less