In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Disable PSR-SU on Parade 08-01 TCON too Stuart Hayhurst has found that both at bootup and fullscreen VA-API video is leading to black screens for around 1 second and kernel WARNING [1] traces when calling dmub_psr_enable() with Parade 08-01 TCON. These symptoms all go away with PSR-SU disabled for this TCON, so disable it for now while DMUB traces [2] from the failure can be analyzed and the failure state properly root caused. (cherry picked from commit afb634a6823d8d9db23c5fb04f79c5549349628b)

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix race between laundromat and free_stateid There is a race between laundromat handling of revoked delegations and a client sending free_stateid operation. Laundromat thread finds that delegation has expired and needs to be revoked so it marks the delegation stid revoked and it puts it on a reaper list but then it unlock the state lock and the actual delegation revocation happens without the lock. Once the stid is marked revoked a racing free_stateid processing thread does the following (1) it calls list_del_init() which removes it from the reaper list and (2) frees the delegation stid structure. The laundromat thread ends up not calling the revoke_delegation() function for this particular delegation but that means it will no release the lock lease that exists on the file. Now, a new open for this file comes in and ends up finding that lease list isn't empty and calls nfsd_breaker_owns_lease() which ends up trying to derefence a freed delegation stateid. Leading to the followint use-after-free KASAN warning: kernel: ================================================================== kernel: BUG: KASAN: slab-use-after-free in nfsd_breaker_owns_lease+0x140/0x160 [nfsd] kernel: Read of size 8 at addr ffff0000e73cd0c8 by task nfsd/6205 kernel: kernel: CPU: 2 UID: 0 PID: 6205 Comm: nfsd Kdump: loaded Not tainted 6.11.0-rc7+ #9 kernel: Hardware name: Apple Inc. Apple Virtualization Generic Platform, BIOS 2069.0.0.0.0 08/03/2024 kernel: Call trace: kernel: dump_backtrace+0x98/0x120 kernel: show_stack+0x1c/0x30 kernel: dump_stack_lvl+0x80/0xe8 kernel: print_address_description.constprop.0+0x84/0x390 kernel: print_report+0xa4/0x268 kernel: kasan_report+0xb4/0xf8 kernel: __asan_report_load8_noabort+0x1c/0x28 kernel: nfsd_breaker_owns_lease+0x140/0x160 [nfsd] kernel: nfsd_file_do_acquire+0xb3c/0x11d0 [nfsd] kernel: nfsd_file_acquire_opened+0x84/0x110 [nfsd] kernel: nfs4_get_vfs_file+0x634/0x958 [nfsd] kernel: nfsd4_process_open2+0xa40/0x1a40 [nfsd] kernel: nfsd4_open+0xa08/0xe80 [nfsd] kernel: nfsd4_proc_compound+0xb8c/0x2130 [nfsd] kernel: nfsd_dispatch+0x22c/0x718 [nfsd] kernel: svc_process_common+0x8e8/0x1960 [sunrpc] kernel: svc_process+0x3d4/0x7e0 [sunrpc] kernel: svc_handle_xprt+0x828/0xe10 [sunrpc] kernel: svc_recv+0x2cc/0x6a8 [sunrpc] kernel: nfsd+0x270/0x400 [nfsd] kernel: kthread+0x288/0x310 kernel: ret_from_fork+0x10/0x20 This patch proposes a fixed that's based on adding 2 new additional stid's sc_status values that help coordinate between the laundromat and other operations (nfsd4_free_stateid() and nfsd4_delegreturn()). First to make sure, that once the stid is marked revoked, it is not removed by the nfsd4_free_stateid(), the laundromat take a reference on the stateid. Then, coordinating whether the stid has been put on the cl_revoked list or we are processing FREE_STATEID and need to make sure to remove it from the list, each check that state and act accordingly. If laundromat has added to the cl_revoke list before the arrival of FREE_STATEID, then nfsd4_free_stateid() knows to remove it from the list. If nfsd4_free_stateid() finds that operations arrived before laundromat has placed it on cl_revoke list, it marks the state freed and then laundromat will no longer add it to the list. Also, for nfsd4_delegreturn() when looking for the specified stid, we need to access stid that are marked removed or freeable, it means the laundromat has started processing it but hasn't finished and this delegreturn needs to return nfserr_deleg_revoked and not nfserr_bad_stateid. The latter will not trigger a FREE_STATEID and the lack of it will leave this stid on the cl_revoked list indefinitely.

In the Linux kernel, the following vulnerability has been resolved: ASoC: qcom: Fix NULL Dereference in asoc_qcom_lpass_cpu_platform_probe() A devm_kzalloc() in asoc_qcom_lpass_cpu_platform_probe() could possibly return NULL pointer. NULL Pointer Dereference may be triggerred without addtional check. Add a NULL check for the returned pointer.

In the Linux kernel, the following vulnerability has been resolved: x86: fix user address masking non-canonical speculation issue It turns out that AMD has a "Meltdown Lite(tm)" issue with non-canonical accesses in kernel space. And so using just the high bit to decide whether an access is in user space or kernel space ends up with the good old "leak speculative data" if you have the right gadget using the result: CVE-2020-12965 “Transient Execution of Non-Canonical Accesses“ Now, the kernel surrounds the access with a STAC/CLAC pair, and those instructions end up serializing execution on older Zen architectures, which closes the speculation window. But that was true only up until Zen 5, which renames the AC bit [1]. That improves performance of STAC/CLAC a lot, but also means that the speculation window is now open. Note that this affects not just the new address masking, but also the regular valid_user_address() check used by access_ok(), and the asm version of the sign bit check in the get_user() helpers. It does not affect put_user() or clear_user() variants, since there's no speculative result to be used in a gadget for those operations.

In the Linux kernel, the following vulnerability has been resolved: iommu/vt-d: Fix incorrect pci_for_each_dma_alias() for non-PCI devices Previously, the domain_context_clear() function incorrectly called pci_for_each_dma_alias() to set up context entries for non-PCI devices. This could lead to kernel hangs or other unexpected behavior. Add a check to only call pci_for_each_dma_alias() for PCI devices. For non-PCI devices, domain_context_clear_one() is called directly.

In the Linux kernel, the following vulnerability has been resolved: arm64: probes: Remove broken LDR (literal) uprobe support The simulate_ldr_literal() and simulate_ldrsw_literal() functions are unsafe to use for uprobes. Both functions were originally written for use with kprobes, and access memory with plain C accesses. When uprobes was added, these were reused unmodified even though they cannot safely access user memory. There are three key problems: 1) The plain C accesses do not have corresponding extable entries, and thus if they encounter a fault the kernel will treat these as unintentional accesses to user memory, resulting in a BUG() which will kill the kernel thread, and likely lead to further issues (e.g. lockup or panic()). 2) The plain C accesses are subject to HW PAN and SW PAN, and so when either is in use, any attempt to simulate an access to user memory will fault. Thus neither simulate_ldr_literal() nor simulate_ldrsw_literal() can do anything useful when simulating a user instruction on any system with HW PAN or SW PAN. 3) The plain C accesses are privileged, as they run in kernel context, and in practice can access a small range of kernel virtual addresses. The instructions they simulate have a range of +/-1MiB, and since the simulated instructions must itself be a user instructions in the TTBR0 address range, these can address the final 1MiB of the TTBR1 acddress range by wrapping downwards from an address in the first 1MiB of the TTBR0 address range. In contemporary kernels the last 8MiB of TTBR1 address range is reserved, and accesses to this will always fault, meaning this is no worse than (1). Historically, it was theoretically possible for the linear map or vmemmap to spill into the final 8MiB of the TTBR1 address range, but in practice this is extremely unlikely to occur as this would require either: * Having enough physical memory to fill the entire linear map all the way to the final 1MiB of the TTBR1 address range. * Getting unlucky with KASLR randomization of the linear map such that the populated region happens to overlap with the last 1MiB of the TTBR address range. ... and in either case if we were to spill into the final page there would be larger problems as the final page would alias with error pointers. Practically speaking, (1) and (2) are the big issues. Given there have been no reports of problems since the broken code was introduced, it appears that no-one is relying on probing these instructions with uprobes. Avoid these issues by not allowing uprobes on LDR (literal) and LDRSW (literal), limiting the use of simulate_ldr_literal() and simulate_ldrsw_literal() to kprobes. Attempts to place uprobes on LDR (literal) and LDRSW (literal) will be rejected as arm_probe_decode_insn() will return INSN_REJECTED. In future we can consider introducing working uprobes support for these instructions, but this will require more significant work.

In the Linux kernel, the following vulnerability has been resolved: scsi: ufs: core: Set SDEV_OFFLINE when UFS is shut down There is a history of deadlock if reboot is performed at the beginning of booting. SDEV_QUIESCE was set for all LU's scsi_devices by UFS shutdown, and at that time the audio driver was waiting on blk_mq_submit_bio() holding a mutex_lock while reading the fw binary. After that, a deadlock issue occurred while audio driver shutdown was waiting for mutex_unlock of blk_mq_submit_bio(). To solve this, set SDEV_OFFLINE for all LUs except WLUN, so that any I/O that comes down after a UFS shutdown will return an error. [ 31.907781]I[0: swapper/0: 0] 1 130705007 1651079834 11289729804 0 D( 2) 3 ffffff882e208000 * init [device_shutdown] [ 31.907793]I[0: swapper/0: 0] Mutex: 0xffffff8849a2b8b0: owner[0xffffff882e28cb00 kworker/6:0 :49] [ 31.907806]I[0: swapper/0: 0] Call trace: [ 31.907810]I[0: swapper/0: 0] __switch_to+0x174/0x338 [ 31.907819]I[0: swapper/0: 0] __schedule+0x5ec/0x9cc [ 31.907826]I[0: swapper/0: 0] schedule+0x7c/0xe8 [ 31.907834]I[0: swapper/0: 0] schedule_preempt_disabled+0x24/0x40 [ 31.907842]I[0: swapper/0: 0] __mutex_lock+0x408/0xdac [ 31.907849]I[0: swapper/0: 0] __mutex_lock_slowpath+0x14/0x24 [ 31.907858]I[0: swapper/0: 0] mutex_lock+0x40/0xec [ 31.907866]I[0: swapper/0: 0] device_shutdown+0x108/0x280 [ 31.907875]I[0: swapper/0: 0] kernel_restart+0x4c/0x11c [ 31.907883]I[0: swapper/0: 0] __arm64_sys_reboot+0x15c/0x280 [ 31.907890]I[0: swapper/0: 0] invoke_syscall+0x70/0x158 [ 31.907899]I[0: swapper/0: 0] el0_svc_common+0xb4/0xf4 [ 31.907909]I[0: swapper/0: 0] do_el0_svc+0x2c/0xb0 [ 31.907918]I[0: swapper/0: 0] el0_svc+0x34/0xe0 [ 31.907928]I[0: swapper/0: 0] el0t_64_sync_handler+0x68/0xb4 [ 31.907937]I[0: swapper/0: 0] el0t_64_sync+0x1a0/0x1a4 [ 31.908774]I[0: swapper/0: 0] 49 0 11960702 11236868007 0 D( 2) 6 ffffff882e28cb00 * kworker/6:0 [__bio_queue_enter] [ 31.908783]I[0: swapper/0: 0] Call trace: [ 31.908788]I[0: swapper/0: 0] __switch_to+0x174/0x338 [ 31.908796]I[0: swapper/0: 0] __schedule+0x5ec/0x9cc [ 31.908803]I[0: swapper/0: 0] schedule+0x7c/0xe8 [ 31.908811]I[0: swapper/0: 0] __bio_queue_enter+0xb8/0x178 [ 31.908818]I[0: swapper/0: 0] blk_mq_submit_bio+0x194/0x67c [ 31.908827]I[0: swapper/0: 0] __submit_bio+0xb8/0x19c

In the Linux kernel, the following vulnerability has been resolved: net: fec: don't save PTP state if PTP is unsupported Some platforms (such as i.MX25 and i.MX27) do not support PTP, so on these platforms fec_ptp_init() is not called and the related members in fep are not initialized. However, fec_ptp_save_state() is called unconditionally, which causes the kernel to panic. Therefore, add a condition so that fec_ptp_save_state() is not called if PTP is not supported.

In the Linux kernel, the following vulnerability has been resolved: nouveau/dmem: Fix vulnerability in migrate_to_ram upon copy error The `nouveau_dmem_copy_one` function ensures that the copy push command is sent to the device firmware but does not track whether it was executed successfully. In the case of a copy error (e.g., firmware or hardware failure), the copy push command will be sent via the firmware channel, and `nouveau_dmem_copy_one` will likely report success, leading to the `migrate_to_ram` function returning a dirty HIGH_USER page to the user. This can result in a security vulnerability, as a HIGH_USER page that may contain sensitive or corrupted data could be returned to the user. To prevent this vulnerability, we allocate a zero page. Thus, in case of an error, a non-dirty (zero) page will be returned to the user.

In the Linux kernel, the following vulnerability has been resolved: RDMA/mad: Improve handling of timed out WRs of mad agent Current timeout handler of mad agent acquires/releases mad_agent_priv lock for every timed out WRs. This causes heavy locking contention when higher no. of WRs are to be handled inside timeout handler. This leads to softlockup with below trace in some use cases where rdma-cm path is used to establish connection between peer nodes Trace: ----- BUG: soft lockup - CPU#4 stuck for 26s! [kworker/u128:3:19767] CPU: 4 PID: 19767 Comm: kworker/u128:3 Kdump: loaded Tainted: G OE ------- --- 5.14.0-427.13.1.el9_4.x86_64 #1 Hardware name: Dell Inc. PowerEdge R740/01YM03, BIOS 2.4.8 11/26/2019 Workqueue: ib_mad1 timeout_sends [ib_core] RIP: 0010:__do_softirq+0x78/0x2ac RSP: 0018:ffffb253449e4f98 EFLAGS: 00000246 RAX: 00000000ffffffff RBX: 0000000000000000 RCX: 000000000000001f RDX: 000000000000001d RSI: 000000003d1879ab RDI: fff363b66fd3a86b RBP: ffffb253604cbcd8 R08: 0000009065635f3b R09: 0000000000000000 R10: 0000000000000040 R11: ffffb253449e4ff8 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000040 FS: 0000000000000000(0000) GS:ffff8caa1fc80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd9ec9db900 CR3: 0000000891934006 CR4: 00000000007706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <IRQ> ? show_trace_log_lvl+0x1c4/0x2df ? show_trace_log_lvl+0x1c4/0x2df ? __irq_exit_rcu+0xa1/0xc0 ? watchdog_timer_fn+0x1b2/0x210 ? __pfx_watchdog_timer_fn+0x10/0x10 ? __hrtimer_run_queues+0x127/0x2c0 ? hrtimer_interrupt+0xfc/0x210 ? __sysvec_apic_timer_interrupt+0x5c/0x110 ? sysvec_apic_timer_interrupt+0x37/0x90 ? asm_sysvec_apic_timer_interrupt+0x16/0x20 ? __do_softirq+0x78/0x2ac ? __do_softirq+0x60/0x2ac __irq_exit_rcu+0xa1/0xc0 sysvec_call_function_single+0x72/0x90 </IRQ> <TASK> asm_sysvec_call_function_single+0x16/0x20 RIP: 0010:_raw_spin_unlock_irq+0x14/0x30 RSP: 0018:ffffb253604cbd88 EFLAGS: 00000247 RAX: 000000000001960d RBX: 0000000000000002 RCX: ffff8cad2a064800 RDX: 000000008020001b RSI: 0000000000000001 RDI: ffff8cad5d39f66c RBP: ffff8cad5d39f600 R08: 0000000000000001 R09: 0000000000000000 R10: ffff8caa443e0c00 R11: ffffb253604cbcd8 R12: ffff8cacb8682538 R13: 0000000000000005 R14: ffffb253604cbd90 R15: ffff8cad5d39f66c cm_process_send_error+0x122/0x1d0 [ib_cm] timeout_sends+0x1dd/0x270 [ib_core] process_one_work+0x1e2/0x3b0 ? __pfx_worker_thread+0x10/0x10 worker_thread+0x50/0x3a0 ? __pfx_worker_thread+0x10/0x10 kthread+0xdd/0x100 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x29/0x50 </TASK> Simplified timeout handler by creating local list of timed out WRs and invoke send handler post creating the list. The new method acquires/ releases lock once to fetch the list and hence helps to reduce locking contetiong when processing higher no. of WRs

In the Linux kernel, the following vulnerability has been resolved: thermal: intel: int340x: processor: Fix warning during module unload The processor_thermal driver uses pcim_device_enable() to enable a PCI device, which means the device will be automatically disabled on driver detach. Thus there is no need to call pci_disable_device() again on it. With recent PCI device resource management improvements, e.g. commit f748a07a0b64 ("PCI: Remove legacy pcim_release()"), this problem is exposed and triggers the warining below. [ 224.010735] proc_thermal_pci 0000:00:04.0: disabling already-disabled device [ 224.010747] WARNING: CPU: 8 PID: 4442 at drivers/pci/pci.c:2250 pci_disable_device+0xe5/0x100 ... [ 224.010844] Call Trace: [ 224.010845] <TASK> [ 224.010847] ? show_regs+0x6d/0x80 [ 224.010851] ? __warn+0x8c/0x140 [ 224.010854] ? pci_disable_device+0xe5/0x100 [ 224.010856] ? report_bug+0x1c9/0x1e0 [ 224.010859] ? handle_bug+0x46/0x80 [ 224.010862] ? exc_invalid_op+0x1d/0x80 [ 224.010863] ? asm_exc_invalid_op+0x1f/0x30 [ 224.010867] ? pci_disable_device+0xe5/0x100 [ 224.010869] ? pci_disable_device+0xe5/0x100 [ 224.010871] ? kfree+0x21a/0x2b0 [ 224.010873] pcim_disable_device+0x20/0x30 [ 224.010875] devm_action_release+0x16/0x20 [ 224.010878] release_nodes+0x47/0xc0 [ 224.010880] devres_release_all+0x9f/0xe0 [ 224.010883] device_unbind_cleanup+0x12/0x80 [ 224.010885] device_release_driver_internal+0x1ca/0x210 [ 224.010887] driver_detach+0x4e/0xa0 [ 224.010889] bus_remove_driver+0x6f/0xf0 [ 224.010890] driver_unregister+0x35/0x60 [ 224.010892] pci_unregister_driver+0x44/0x90 [ 224.010894] proc_thermal_pci_driver_exit+0x14/0x5f0 [processor_thermal_device_pci] ... [ 224.010921] ---[ end trace 0000000000000000 ]--- Remove the excess pci_disable_device() calls. [ rjw: Subject and changelog edits ]

In the Linux kernel, the following vulnerability has been resolved: dm vdo: don't refer to dedupe_context after releasing it Clear the dedupe_context pointer in a data_vio whenever ownership of the context is lost, so that vdo can't examine it accidentally.

In the Linux kernel, the following vulnerability has been resolved: drm/xe/oa: Fix overflow in oa batch buffer By default xe_bb_create_job() appends a MI_BATCH_BUFFER_END to batch buffer, this is not a problem if batch buffer is only used once but oa reuses the batch buffer for the same metric and at each call it appends a MI_BATCH_BUFFER_END, printing the warning below and then overflowing. [ 381.072016] ------------[ cut here ]------------ [ 381.072019] xe 0000:00:02.0: [drm] Assertion `bb->len * 4 + bb_prefetch(q->gt) <= size` failed! platform: LUNARLAKE subplatform: 1 graphics: Xe2_LPG / Xe2_HPG 20.04 step B0 media: Xe2_LPM / Xe2_HPM 20.00 step B0 tile: 0 VRAM 0 B GT: 0 type 1 So here checking if batch buffer already have MI_BATCH_BUFFER_END if not append it. v2: - simply fix, suggestion from Ashutosh (cherry picked from commit 9ba0e0f30ca42a98af3689460063edfb6315718a)

In the Linux kernel, the following vulnerability has been resolved: unicode: Don't special case ignorable code points We don't need to handle them separately. Instead, just let them decompose/casefold to themselves.

In the Linux kernel, the following vulnerability has been resolved: bpf: support non-r10 register spill/fill to/from stack in precision tracking Use instruction (jump) history to record instructions that performed register spill/fill to/from stack, regardless if this was done through read-only r10 register, or any other register after copying r10 into it *and* potentially adjusting offset. To make this work reliably, we push extra per-instruction flags into instruction history, encoding stack slot index (spi) and stack frame number in extra 10 bit flags we take away from prev_idx in instruction history. We don't touch idx field for maximum performance, as it's checked most frequently during backtracking. This change removes basically the last remaining practical limitation of precision backtracking logic in BPF verifier. It fixes known deficiencies, but also opens up new opportunities to reduce number of verified states, explored in the subsequent patches. There are only three differences in selftests' BPF object files according to veristat, all in the positive direction (less states). File Program Insns (A) Insns (B) Insns (DIFF) States (A) States (B) States (DIFF) -------------------------------------- ------------- --------- --------- ------------- ---------- ---------- ------------- test_cls_redirect_dynptr.bpf.linked3.o cls_redirect 2987 2864 -123 (-4.12%) 240 231 -9 (-3.75%) xdp_synproxy_kern.bpf.linked3.o syncookie_tc 82848 82661 -187 (-0.23%) 5107 5073 -34 (-0.67%) xdp_synproxy_kern.bpf.linked3.o syncookie_xdp 85116 84964 -152 (-0.18%) 5162 5130 -32 (-0.62%) Note, I avoided renaming jmp_history to more generic insn_hist to minimize number of lines changed and potential merge conflicts between bpf and bpf-next trees. Notice also cur_hist_entry pointer reset to NULL at the beginning of instruction verification loop. This pointer avoids the problem of relying on last jump history entry's insn_idx to determine whether we already have entry for current instruction or not. It can happen that we added jump history entry because current instruction is_jmp_point(), but also we need to add instruction flags for stack access. In this case, we don't want to entries, so we need to reuse last added entry, if it is present. Relying on insn_idx comparison has the same ambiguity problem as the one that was fixed recently in [0], so we avoid that. [0] https://patchwork.kernel.org/project/netdevbpf/patch/20231110002638.4168352-3-andrii@kernel.org/

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix uninitialized pointer free in add_inode_ref() The add_inode_ref() function does not initialize the "name" struct when it is declared. If any of the following calls to "read_one_inode() returns NULL, dir = read_one_inode(root, parent_objectid); if (!dir) { ret = -ENOENT; goto out; } inode = read_one_inode(root, inode_objectid); if (!inode) { ret = -EIO; goto out; } then "name.name" would be freed on "out" before being initialized. out: ... kfree(name.name); This issue was reported by Coverity with CID 1526744.

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix uninitialized pointer free on read_alloc_one_name() error The function read_alloc_one_name() does not initialize the name field of the passed fscrypt_str struct if kmalloc fails to allocate the corresponding buffer. Thus, it is not guaranteed that fscrypt_str.name is initialized when freeing it. This is a follow-up to the linked patch that fixes the remaining instances of the bug introduced by commit e43eec81c516 ("btrfs: use struct qstr instead of name and namelen pairs").

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix user-after-free from session log off There is racy issue between smb2 session log off and smb2 session setup. It will cause user-after-free from session log off. This add session_lock when setting SMB2_SESSION_EXPIRED and referece count to session struct not to free session while it is being used.

In the Linux kernel, the following vulnerability has been resolved: tcp: fix mptcp DSS corruption due to large pmtu xmit Syzkaller was able to trigger a DSS corruption: TCP: request_sock_subflow_v4: Possible SYN flooding on port [::]:20002. Sending cookies. ------------[ cut here ]------------ WARNING: CPU: 0 PID: 5227 at net/mptcp/protocol.c:695 __mptcp_move_skbs_from_subflow+0x20a9/0x21f0 net/mptcp/protocol.c:695 Modules linked in: CPU: 0 UID: 0 PID: 5227 Comm: syz-executor350 Not tainted 6.11.0-syzkaller-08829-gaf9c191ac2a0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 RIP: 0010:__mptcp_move_skbs_from_subflow+0x20a9/0x21f0 net/mptcp/protocol.c:695 Code: 0f b6 dc 31 ff 89 de e8 b5 dd ea f5 89 d8 48 81 c4 50 01 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc e8 98 da ea f5 90 <0f> 0b 90 e9 47 ff ff ff e8 8a da ea f5 90 0f 0b 90 e9 99 e0 ff ff RSP: 0018:ffffc90000006db8 EFLAGS: 00010246 RAX: ffffffff8ba9df18 RBX: 00000000000055f0 RCX: ffff888030023c00 RDX: 0000000000000100 RSI: 00000000000081e5 RDI: 00000000000055f0 RBP: 1ffff110062bf1ae R08: ffffffff8ba9cf12 R09: 1ffff110062bf1b8 R10: dffffc0000000000 R11: ffffed10062bf1b9 R12: 0000000000000000 R13: dffffc0000000000 R14: 00000000700cec61 R15: 00000000000081e5 FS: 000055556679c380(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020287000 CR3: 0000000077892000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <IRQ> move_skbs_to_msk net/mptcp/protocol.c:811 [inline] mptcp_data_ready+0x29c/0xa90 net/mptcp/protocol.c:854 subflow_data_ready+0x34a/0x920 net/mptcp/subflow.c:1490 tcp_data_queue+0x20fd/0x76c0 net/ipv4/tcp_input.c:5283 tcp_rcv_established+0xfba/0x2020 net/ipv4/tcp_input.c:6237 tcp_v4_do_rcv+0x96d/0xc70 net/ipv4/tcp_ipv4.c:1915 tcp_v4_rcv+0x2dc0/0x37f0 net/ipv4/tcp_ipv4.c:2350 ip_protocol_deliver_rcu+0x22e/0x440 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x341/0x5f0 net/ipv4/ip_input.c:233 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314 __netif_receive_skb_one_core net/core/dev.c:5662 [inline] __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5775 process_backlog+0x662/0x15b0 net/core/dev.c:6107 __napi_poll+0xcb/0x490 net/core/dev.c:6771 napi_poll net/core/dev.c:6840 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:6962 handle_softirqs+0x2c5/0x980 kernel/softirq.c:554 do_softirq+0x11b/0x1e0 kernel/softirq.c:455 </IRQ> <TASK> __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:382 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline] __dev_queue_xmit+0x1764/0x3e80 net/core/dev.c:4451 dev_queue_xmit include/linux/netdevice.h:3094 [inline] neigh_hh_output include/net/neighbour.h:526 [inline] neigh_output include/net/neighbour.h:540 [inline] ip_finish_output2+0xd41/0x1390 net/ipv4/ip_output.c:236 ip_local_out net/ipv4/ip_output.c:130 [inline] __ip_queue_xmit+0x118c/0x1b80 net/ipv4/ip_output.c:536 __tcp_transmit_skb+0x2544/0x3b30 net/ipv4/tcp_output.c:1466 tcp_transmit_skb net/ipv4/tcp_output.c:1484 [inline] tcp_mtu_probe net/ipv4/tcp_output.c:2547 [inline] tcp_write_xmit+0x641d/0x6bf0 net/ipv4/tcp_output.c:2752 __tcp_push_pending_frames+0x9b/0x360 net/ipv4/tcp_output.c:3015 tcp_push_pending_frames include/net/tcp.h:2107 [inline] tcp_data_snd_check net/ipv4/tcp_input.c:5714 [inline] tcp_rcv_established+0x1026/0x2020 net/ipv4/tcp_input.c:6239 tcp_v4_do_rcv+0x96d/0xc70 net/ipv4/tcp_ipv4.c:1915 sk_backlog_rcv include/net/sock.h:1113 [inline] __release_sock+0x214/0x350 net/core/sock.c:3072 release_sock+0x61/0x1f0 net/core/sock.c:3626 mptcp_push_ ---truncated---

In the Linux kernel, the following vulnerability has been resolved: blk-rq-qos: fix crash on rq_qos_wait vs. rq_qos_wake_function race We're seeing crashes from rq_qos_wake_function that look like this: BUG: unable to handle page fault for address: ffffafe180a40084 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 100000067 P4D 100000067 PUD 10027c067 PMD 10115d067 PTE 0 Oops: Oops: 0002 [#1] PREEMPT SMP PTI CPU: 17 UID: 0 PID: 0 Comm: swapper/17 Not tainted 6.12.0-rc3-00013-geca631b8fe80 #11 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 RIP: 0010:_raw_spin_lock_irqsave+0x1d/0x40 Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 41 54 9c 41 5c fa 65 ff 05 62 97 30 4c 31 c0 ba 01 00 00 00 <f0> 0f b1 17 75 0a 4c 89 e0 41 5c c3 cc cc cc cc 89 c6 e8 2c 0b 00 RSP: 0018:ffffafe180580ca0 EFLAGS: 00010046 RAX: 0000000000000000 RBX: ffffafe180a3f7a8 RCX: 0000000000000011 RDX: 0000000000000001 RSI: 0000000000000003 RDI: ffffafe180a40084 RBP: 0000000000000000 R08: 00000000001e7240 R09: 0000000000000011 R10: 0000000000000028 R11: 0000000000000888 R12: 0000000000000002 R13: ffffafe180a40084 R14: 0000000000000000 R15: 0000000000000003 FS: 0000000000000000(0000) GS:ffff9aaf1f280000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffafe180a40084 CR3: 000000010e428002 CR4: 0000000000770ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <IRQ> try_to_wake_up+0x5a/0x6a0 rq_qos_wake_function+0x71/0x80 __wake_up_common+0x75/0xa0 __wake_up+0x36/0x60 scale_up.part.0+0x50/0x110 wb_timer_fn+0x227/0x450 ... So rq_qos_wake_function() calls wake_up_process(data->task), which calls try_to_wake_up(), which faults in raw_spin_lock_irqsave(&p->pi_lock). p comes from data->task, and data comes from the waitqueue entry, which is stored on the waiter's stack in rq_qos_wait(). Analyzing the core dump with drgn, I found that the waiter had already woken up and moved on to a completely unrelated code path, clobbering what was previously data->task. Meanwhile, the waker was passing the clobbered garbage in data->task to wake_up_process(), leading to the crash. What's happening is that in between rq_qos_wake_function() deleting the waitqueue entry and calling wake_up_process(), rq_qos_wait() is finding that it already got a token and returning. The race looks like this: rq_qos_wait() rq_qos_wake_function() ============================================================== prepare_to_wait_exclusive() data->got_token = true; list_del_init(&curr->entry); if (data.got_token) break; finish_wait(&rqw->wait, &data.wq); ^- returns immediately because list_empty_careful(&wq_entry->entry) is true ... return, go do something else ... wake_up_process(data->task) (NO LONGER VALID!)-^ Normally, finish_wait() is supposed to synchronize against the waker. But, as noted above, it is returning immediately because the waitqueue entry has already been removed from the waitqueue. The bug is that rq_qos_wake_function() is accessing the waitqueue entry AFTER deleting it. Note that autoremove_wake_function() wakes the waiter and THEN deletes the waitqueue entry, which is the proper order. Fix it by swapping the order. We also need to use list_del_init_careful() to match the list_empty_careful() in finish_wait().