Linux

In the Linux kernel, the following vulnerability has been resolved: KVM: Don't WARN if memory is dirtied without a vCPU when the VM is dying When marking a page dirty, complain about not having a running/loaded vCPU if and only if the VM is still alive, i.e. its refcount is non-zero. This will allow fixing a memory leak for x86 SEV-ES guests without hitting what is effectively a false positive on the WARN. For some SEV-ES VM-Exits, KVM keeps a writable mapping of a guest page across an exit to userspace, and typically unmaps the page on the next KVM_RUN. But if userspace never calls KVM_RUN after such an exit, then KVM needs to unmap the page when the vCPU is destroyed, which in turn triggers the WARN about not having a running vCPU. Alternatively, SEV-ES could temporarily load the vCPU to suppress the WARN, as is done in nested_vmx_free_vcpu() (but for completely unrelated reasons; suppressing WARN from nested_put_vmcs12_pages() is pure happenstance). But loading a vCPU during destruction is gross (ideally nVMX code would be cleaned up), risks complicating the SEV-ES code (KVM would need to ensure the temporarily load()+put() only runs when the vCPU isn't already loaded), and is ultimately pointless. The motivation for the WARN is to guard against KVM dirtying guest memory without pushing the corresponding GFN to the active vCPU's dirty ring, e.g. to ensure userspace doesn't miss a dirty page. But for the VM's refcount to reach zero, there can't be _any_ userspace mappings to the dirty ring, as mapping the dirty ring requires doing mmap() on the vCPU FD. I.e. if userspace had a valid mapping for the dirty ring, then the vCPU file and thus the owning VM would still be alive. And so since userspace can't possibly reach the dirty ring, whether or not KVM technically "misses" a push to the dirty ring is irrelevant.Show less

In the Linux kernel, the following vulnerability has been resolved: agp/amd64: Fix broken error propagation in agp_amd64_probe() A NULL pointer dereference was observed in the AMD64 AGP driver when running in a virtualized environment (e.g. qemu/kvm) without a physical AMD northbridge. The crash occurs in amd64_fetch_size() when attempting to dereference the pointer returned by node_to_amd_nb(0). The root cause of this crash is broken error propagation in agp_amd64_probe(): When no AMD northbridges are found, cache_nbs() correctly returns -ENODEV. However, the probe function erroneously checks the return value against exactly -1, rather than < 0. As a result, the hardware absence error is masked, allowing the driver to improperly proceed with initialization. It eventually calls agp_add_bridge(), which invokes amd64_fetch_size(). Since the hardware does not exist, node_to_amd_nb(0) returns NULL, leading to a General Protection Fault (GPF) when accessing its ->misc member. Fix the issue by correcting the error check in agp_amd64_probe() to abort properly when cache_nbs() returns any negative error code. This prevents the driver from erroneously proceeding without hardware, thereby avoiding the subsequent NULL pointer dereference at its source.Show less

In the Linux kernel, the following vulnerability has been resolved: net: mana: Use pci_name() for debugfs directory naming Use pci_name(pdev) for the per-device debugfs directory instead of hardcoded "0" for PFs and pci_slot_name(pdev->slot) for VFs. The previous approach had two issues: 1. pci_slot_name() dereferences pdev->slot, which can be NULL for VFs in environments like generic VFIO passthrough or nested KVM, causing a NULL pointer dereference. 2. Multiple PFs would all use "0", and VFs across different PCI domains or buses could share the same slot name, leading to -EEXIST errors from debugfs_create_dir(). pci_name(pdev) returns the unique BDF address, is always valid, and is unique across the system.Show less

In the Linux kernel, the following vulnerability has been resolved: net: dsa: remove redundant netdev_lock_ops() from conduit ethtool ops DSA replaces the conduit (master) device's ethtool_ops with its own wrappers that aggregate stats from both the conduit and DSA switch ports. Taking the lock again inside the DSA wrappers causes a deadlock. Stumbled upon this when booting qemu with fbnic and CONFIG_NET_DSA_LOOP=y (which looks like some kind of testing device that auto-populates the ports of eth0). `ethtool -i` is enough to deadlock. This means we have basically zero coverage for DSA stuff with real ops locked devs. Remove the redundant netdev_lock_ops()/netdev_unlock_ops() calls from the DSA conduit ethtool wrappers.Show less

In the Linux kernel, the following vulnerability has been resolved: vfio/pci: Clean up DMABUFs before disabling function On device shutdown, make vfio_pci_core_close_device() call vfio_pci_dma_buf_cleanup() before the function is disabled via vfio_pci_core_disable(). This ensures that all access via DMABUFs is revoked before the function's BARs become inaccessible. This fixes an issue where, if the function is disabled first, a tiny window exists in which the function's MSE is cleared and yet BARs could still be accessed via the DMABUF. The resources would also be freed and up for grabs by a different driver.Show less

In the Linux kernel, the following vulnerability has been resolved: io_uring/napi: cap busy_poll_to 10 msec Currently there's no cap on the maximum amount of time that napi is allowed to poll if no events are found, which can lead to kernel complaints on a task being stuck as there's no conditional rescheduling done within that loop. Just cap it to 10 msec in total, that's already way above any kind of sane value that will reap any benefits, yet low enough that it's nowhere near being able to trigger preemption complaints.Show less

In the Linux kernel, the following vulnerability has been resolved: nilfs2: reject zero bd_oblocknr in nilfs_ioctl_mark_blocks_dirty() nilfs_ioctl_mark_blocks_dirty() uses bd_oblocknr to detect dead blocks by comparing it with the current block number bd_blocknr. If they differ, the block is considered dead and skipped. However, bd_oblocknr should never be 0 since block 0 typically stores the primary superblock and is never a valid GC target block. A corrupted ioctl request with bd_oblocknr set to 0 causes the comparison to incorrectly match when the lookup returns -ENOENT and sets bd_blocknr to 0, bypassing the dead block check and calling nilfs_bmap_mark() on a non-existent block. This causes nilfs_btree_do_lookup() to return -ENOENT, triggering the WARN_ON(ret == -ENOENT). Fix this by rejecting ioctl requests with bd_oblocknr set to 0 at the beginning of each iteration. [ryusuke: slightly modified the commit message and comments for accuracy]Show less

In the Linux kernel, the following vulnerability has been resolved: blk-wbt: remove WARN_ON_ONCE from wbt_init_enable_default() wbt_init_enable_default() uses WARN_ON_ONCE to check for failures from wbt_alloc() and wbt_init(). However, both are expected failure paths: - wbt_alloc() can return NULL under memory pressure (-ENOMEM) - wbt_init() can fail with -EBUSY if wbt is already registered syzbot triggers this by injecting memory allocation failures during MTD partition creation via ioctl(BLKPG), causing a spurious warning. wbt_init_enable_default() is a best-effort initialization called from blk_register_queue() with a void return type. Failure simply means the disk operates without writeback throttling, which is harmless. Replace WARN_ON_ONCE with plain if-checks, consistent with how wbt_set_lat() in the same file already handles these failures. Add a pr_warn() for the wbt_init() failure to retain diagnostic information without triggering a full stack trace.Show less

In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7925: prevent NULL pointer dereference in mt7925_tx_check_aggr() Move the NULL check for 'sta' before dereferencing it to prevent a possible crash.Show less

In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7921: Place upper limit on station AID Any station configured with an AID over 20 causes a firmware crash. This situation occurred in our testing using an AP interface on 7922 hardware, with a modified hostapd, sourced from Mediatek's OpenWRT feeds. In stock hostapd, station AIDs begin counting at 1, and this configuration is prevented with an upper limit on associated stations. However, the modified hostapd began allocation at 65, which caused the firmware to crash. This fix does not allow these AIDs to work, but will prevent the firmware crash. This crash was only seen on IFTYPE_AP interfaces, and the fix does not appear to have an effect on IFTYPE_STATION behavior.Show less

In the Linux kernel, the following vulnerability has been resolved: drm/amd/ras: Fix NULL deref in ras_core_ras_interrupt_detected() Fixes a NULL pointer dereference when ras_core is NULL and ras_core->dev is accessed in the error path. Reported by: Dan Carpenter <dan.carpenter@linaro.org>Show less

In the Linux kernel, the following vulnerability has been resolved: drm/amd/ras: Fix NULL deref in ras_core_get_utc_second_timestamp() ras_core_get_utc_second_timestamp() retrieves the current UTC timestamp (in seconds since the Unix epoch) through a platform-specific RAS system callback and is used for timestamping RAS error events. The function checks ras_core in the conditional statement before calling the sys_fn callback. However, when the condition fails, the function prints an error message using ras_core->dev. If ras_core is NULL, this can lead to a potential NULL pointer dereference when accessing ras_core->dev. Add an early NULL check for ras_core at the beginning of the function and return 0 when the pointer is not valid. This prevents the dereference and makes the control flow clearer.Show less

In the Linux kernel, the following vulnerability has been resolved: padata: Put CPU offline callback in ONLINE section to allow failure syzbot reported the following warning: DEAD callback error for CPU1 WARNING: kernel/cpu.c:1463 at _cpu_down+0x759/0x1020 kernel/cpu.c:1463, CPU#0: syz.0.1960/14614 at commit 4ae12d8bd9a8 ("Merge tag 'kbuild-fixes-7.0-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux") which tglx traced to padata_cpu_dead() given it's the only sub-CPUHP_TEARDOWN_CPU callback that returns an error. Failure isn't allowed in hotplug states before CPUHP_TEARDOWN_CPU so move the CPU offline callback to the ONLINE section where failure is possible.Show less

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Avoid NULL dereference in dc_dmub_srv error paths In dc_dmub_srv_log_diagnostic_data() and dc_dmub_srv_enable_dpia_trace(). Both functions check: if (!dc_dmub_srv || !dc_dmub_srv->dmub) and then call DC_LOG_ERROR() inside that block. DC_LOG_ERROR() uses dc_dmub_srv->ctx internally. So if dc_dmub_srv is NULL, the logging itself can dereference a NULL pointer and cause a crash. Fix this by splitting the checks. First check if dc_dmub_srv is NULL and return immediately. Then check dc_dmub_srv->dmub and log the error only when dc_dmub_srv is valid. Fixes the below: ../display/dc/dc_dmub_srv.c:962 dc_dmub_srv_log_diagnostic_data() error: we previously assumed 'dc_dmub_srv' could be null (see line 961) ../display/dc/dc_dmub_srv.c:1167 dc_dmub_srv_enable_dpia_trace() error: we previously assumed 'dc_dmub_srv' could be null (see line 1166)Show less

In the Linux kernel, the following vulnerability has been resolved: iommu/riscv: Remove overflows on the invalidation path Since RISC-V supports a sign extended page table it should support a gather->end of ULONG_MAX, but if this happens it will infinite loop because of the overflow. Also avoid overflow computing the length by moving the +1 to the other side of the <Show less

In the Linux kernel, the following vulnerability has been resolved: fuse: fix uninit-value in fuse_dentry_revalidate() fuse_dentry_revalidate() may be called with a dentry that didn't had ->d_time initialised. The issue was found with KMSAN, where lookup_open() calls __d_alloc(), followed by d_revalidate(), as shown below: ===================================================== BUG: KMSAN: uninit-value in fuse_dentry_revalidate+0x150/0x13d0 fs/fuse/dir.c:394 fuse_dentry_revalidate+0x150/0x13d0 fs/fuse/dir.c:394 d_revalidate fs/namei.c:1030 [inline] lookup_open fs/namei.c:4405 [inline] open_last_lookups fs/namei.c:4583 [inline] path_openat+0x1614/0x64c0 fs/namei.c:4827 do_file_open+0x2aa/0x680 fs/namei.c:4859 [...] Uninit was created at: slab_post_alloc_hook mm/slub.c:4466 [inline] slab_alloc_node mm/slub.c:4788 [inline] kmem_cache_alloc_lru_noprof+0x382/0x1280 mm/slub.c:4807 __d_alloc+0x55/0xa00 fs/dcache.c:1740 d_alloc_parallel+0x99/0x2740 fs/dcache.c:2604 lookup_open fs/namei.c:4398 [inline] open_last_lookups fs/namei.c:4583 [inline] path_openat+0x135f/0x64c0 fs/namei.c:4827 do_file_open+0x2aa/0x680 fs/namei.c:4859 [...] =====================================================Show less

In the Linux kernel, the following vulnerability has been resolved: soc/tegra: cbb: Fix cross-fabric target timeout lookup When a fabric receives an error interrupt, the error may have occurred on a different fabric. The target timeout lookup was using the wrong base address (cbb->regs) with offsets from a different fabric's target map, causing a kernel page fault. Unable to handle kernel paging request at virtual address ffff80000954cc00 pc : tegra234_cbb_get_tmo_slv+0xc/0x28 Call trace: tegra234_cbb_get_tmo_slv+0xc/0x28 print_err_notifier+0x6c0/0x7d0 tegra234_cbb_isr+0xe4/0x1b4 Add tegra234_cbb_get_fabric() to look up the correct fabric device using fab_id, and use its base address for accessing target timeout registers.Show less

In the Linux kernel, the following vulnerability has been resolved: ocfs2/dlm: fix off-by-one in dlm_match_regions() region comparison The local-vs-remote region comparison loop uses '<=' instead of '<', causing it to read one entry past the valid range of qr_regions. The other loops in the same function correctly use '<'. Fix the loop condition to use '<' for consistency and correctness.Show less

In the Linux kernel, the following vulnerability has been resolved: power: supply: max77705: Free allocated workqueue and fix removal order Use devm interface for allocating workqueue to fix two bugs at the same time: 1. Driver leaks the memory on remove(), because the workqueue is not destroyed. 2. Driver allocates workqueue and then registers interrupt handlers with devm interface. This means that probe error paths will not use a reversed order, but first destroy the workqueue and then, via devm release handlers, free the interrupt. The interrupt handler schedules work on this exact workqueue, thus if interrupt is hit in this short time window - after destroying workqueue, but before devm() frees the interrupt - the schedulled work will lead to use of freed memory. Change is not equivalent in the workqueue itself: use non-legacy API which does not set (__WQ_LEGACY | WQ_MEM_RECLAIM). The workqueue is used to update power supply (power_supply_changed()) status, thus there is no point to run it for memory reclaim. Note that dev_name() is not directly used in second argument to prevent possible unlikely parsing any "%" character in device name as format.Show less

In the Linux kernel, the following vulnerability has been resolved: pinctrl: pinconf-generic: Fully validate 'pinmux' property The pinconf_generic_parse_dt_pinmux() assumes that the 'pinmux' property is not empty when present. This might be not true. With that, the allocator will give a special value in return and not NULL which lead to the crash when trying to access that (invalid) memory. Fix that by fully validating 'pinmux' value, including its length.Show less