Linux Linux Kernel vulnerabilities

In the Linux kernel, the following vulnerability has been resolved: ntfs3: fix circular locking dependency in run_unpack_ex Syzbot reported a circular locking dependency between wnd->rw_lock (sbi->used.bitmap) and ni->file.run_lock. The deadlock scenario: 1. ntfs_extend_mft() takes ni->file.run_lock then wnd->rw_lock. 2. run_unpack_ex() takes wnd->rw_lock then tries to acquire ni->file.run_lock inside ntfs_refresh_zone(). This creates an AB-BA deadlock. Fix this by using down_read_trylock() instead of down_read() when acquiring run_lock in run_unpack_ex(). If the lock is contended, skip ntfs_refresh_zone() - the MFT zone will be refreshed on the next MFT operation. This breaks the circular dependency since we never block waiting for run_lock while holding wnd->rw_lock.

In the Linux kernel, the following vulnerability has been resolved: pstore: ram_core: fix incorrect success return when vmap() fails In persistent_ram_vmap(), vmap() may return NULL on failure. If offset is non-zero, adding offset_in_page(start) causes the function to return a non-NULL pointer even though the mapping failed. persistent_ram_buffer_map() therefore incorrectly returns success. Subsequent access to prz->buffer may dereference an invalid address and cause crashes. Add proper NULL checking for vmap() failures.

In the Linux kernel, the following vulnerability has been resolved: fbcon: check return value of con2fb_acquire_newinfo() If fbcon_open() fails when called from con2fb_acquire_newinfo() then info->fbcon_par pointer remains NULL which is later dereferenced. Add check for return value of the function con2fb_acquire_newinfo() to avoid it. Found by Linux Verification Center (linuxtesting.org) with SVACE.

In the Linux kernel, the following vulnerability has been resolved: io_uring/zcrx: fix user_ref race between scrub and refill paths The io_zcrx_put_niov_uref() function uses a non-atomic check-then-decrement pattern (atomic_read followed by separate atomic_dec) to manipulate user_refs. This is serialized against other callers by rq_lock, but io_zcrx_scrub() modifies the same counter with atomic_xchg() WITHOUT holding rq_lock. On SMP systems, the following race exists: CPU0 (refill, holds rq_lock) CPU1 (scrub, no rq_lock) put_niov_uref: atomic_read(uref) - 1 // window opens atomic_xchg(uref, 0) - 1 return_niov_freelist(niov) [PUSH #1] // window closes atomic_dec(uref) - wraps to -1 returns true return_niov(niov) return_niov_freelist(niov) [PUSH #2: DOUBLE-FREE] The same niov is pushed to the freelist twice, causing free_count to exceed nr_iovs. Subsequent freelist pushes then perform an out-of-bounds write (a u32 value) past the kvmalloc'd freelist array into the adjacent slab object. Fix this by replacing the non-atomic read-then-dec in io_zcrx_put_niov_uref() with an atomic_try_cmpxchg loop that atomically tests and decrements user_refs. This makes the operation safe against concurrent atomic_xchg from scrub without requiring scrub to acquire rq_lock. [pavel: removed a warning and a comment]

In the Linux kernel, the following vulnerability has been resolved: fs/buffer: add alert in try_to_free_buffers() for folios without buffers try_to_free_buffers() can be called on folios with no buffers attached when filemap_release_folio() is invoked on a folio belonging to a mapping with AS_RELEASE_ALWAYS set but no release_folio operation defined. In such cases, folio_needs_release() returns true because of the AS_RELEASE_ALWAYS flag, but the folio has no private buffer data. This causes try_to_free_buffers() to call drop_buffers() on a folio with no buffers, leading to a null pointer dereference. Adding a check in try_to_free_buffers() to return early if the folio has no buffers attached, with WARN_ON_ONCE() to alert about the misconfiguration. This provides defensive hardening.

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: fix NULL pointer issue buffer funcs If SDMA block not enabled, buffer_funcs will not initialize, fix the null pointer issue if buffer_funcs not initialized.

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu/ras: Move ras data alloc before bad page check In the rare event if eeprom has only invalid address entries, allocation is skipped, this causes following NULL pointer issue [ 547.103445] BUG: kernel NULL pointer dereference, address: 0000000000000010 [ 547.118897] #PF: supervisor read access in kernel mode [ 547.130292] #PF: error_code(0x0000) - not-present page [ 547.141689] PGD 124757067 P4D 0 [ 547.148842] Oops: 0000 [#1] PREEMPT SMP NOPTI [ 547.158504] CPU: 49 PID: 8167 Comm: cat Tainted: G OE 6.8.0-38-generic #38-Ubuntu [ 547.177998] Hardware name: Supermicro AS -8126GS-TNMR/H14DSG-OD, BIOS 1.7 09/12/2025 [ 547.195178] RIP: 0010:amdgpu_ras_sysfs_badpages_read+0x2f2/0x5d0 [amdgpu] [ 547.210375] Code: e8 63 78 82 c0 45 31 d2 45 3b 75 08 48 8b 45 a0 73 44 44 89 f1 48 8b 7d 88 48 89 ca 48 c1 e2 05 48 29 ca 49 8b 4d 00 48 01 d1 <48> 83 79 10 00 74 17 49 63 f2 48 8b 49 08 41 83 c2 01 48 8d 34 76 [ 547.252045] RSP: 0018:ffa0000067287ac0 EFLAGS: 00010246 [ 547.263636] RAX: ff11000167c28130 RBX: ff11000127600000 RCX: 0000000000000000 [ 547.279467] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ff11000125b1c800 [ 547.295298] RBP: ffa0000067287b50 R08: 0000000000000000 R09: 0000000000000000 [ 547.311129] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 547.326959] R13: ff11000217b1de00 R14: 0000000000000000 R15: 0000000000000092 [ 547.342790] FS: 0000746e59d14740(0000) GS:ff11017dfda80000(0000) knlGS:0000000000000000 [ 547.360744] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 547.373489] CR2: 0000000000000010 CR3: 000000019585e001 CR4: 0000000000f71ef0 [ 547.389321] PKRU: 55555554 [ 547.395316] Call Trace: [ 547.400737] <TASK> [ 547.405386] ? show_regs+0x6d/0x80 [ 547.412929] ? __die+0x24/0x80 [ 547.419697] ? page_fault_oops+0x99/0x1b0 [ 547.428588] ? do_user_addr_fault+0x2ee/0x6b0 [ 547.438249] ? exc_page_fault+0x83/0x1b0 [ 547.446949] ? asm_exc_page_fault+0x27/0x30 [ 547.456225] ? amdgpu_ras_sysfs_badpages_read+0x2f2/0x5d0 [amdgpu] [ 547.470040] ? mas_wr_modify+0xcd/0x140 [ 547.478548] sysfs_kf_bin_read+0x63/0xb0 [ 547.487248] kernfs_file_read_iter+0xa1/0x190 [ 547.496909] kernfs_fop_read_iter+0x25/0x40 [ 547.506182] vfs_read+0x255/0x390 This also result in space left assigned to negative values. Moving data alloc call before bad page check resolves both the issue.

In the Linux kernel, the following vulnerability has been resolved: jfs: nlink overflow in jfs_rename If nlink is maximal for a directory (-1) and inside that directory you perform a rename for some child directory (not moving from the parent), then the nlink of the first directory is first incremented and later decremented. Normally this is fine, but when nlink = -1 this causes a wrap around to 0, and then drop_nlink issues a warning. After applying the patch syzbot no longer issues any warnings. I also ran some basic fs tests to look for any regressions.

In the Linux kernel, the following vulnerability has been resolved: misc: bcm_vk: Fix possible null-pointer dereferences in bcm_vk_read() In the function bcm_vk_read(), the pointer entry is checked, indicating that it can be NULL. If entry is NULL and rc is set to -EMSGSIZE, the following code may cause null-pointer dereferences: struct vk_msg_blk tmp_msg = entry->to_h_msg[0]; set_msg_id(&tmp_msg, entry->usr_msg_id); tmp_msg.size = entry->to_h_blks - 1; To prevent these possible null-pointer dereferences, copy to_h_msg, usr_msg_id, and to_h_blks from iter into temporary variables, and return these temporary variables to the application instead of accessing them through a potentially NULL entry.

In the Linux kernel, the following vulnerability has been resolved: misc: ti_fpc202: fix a potential memory leak in probe function Use for_each_child_of_node_scoped() to simplify the code and ensure the device node reference is automatically released when the loop scope ends.

In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: handle attr_set_size() errors when truncating files If attr_set_size() fails while truncating down, the error is silently ignored and the inode may be left in an inconsistent state.

In the Linux kernel, the following vulnerability has been resolved: memory: mtk-smi: fix device leaks on common probe Make sure to drop the reference taken when looking up the SMI device during common probe on late probe failure (e.g. probe deferral) and on driver unbind.

In the Linux kernel, the following vulnerability has been resolved: memory: mtk-smi: fix device leak on larb probe Make sure to drop the reference taken when looking up the SMI device during larb probe on late probe failure (e.g. probe deferral) and on driver unbind.

In the Linux kernel, the following vulnerability has been resolved: ASoC: SOF: ipc4-topology: Correct the allocation size for bytes controls The size of the data behind of scontrol->ipc_control_data for bytes controls is: [1] sizeof(struct sof_ipc4_control_data) + // kernel only struct [2] sizeof(struct sof_abi_hdr)) + payload The max_size specifies the size of [2] and it is coming from topology. Change the function to take this into account and allocate adequate amount of memory behind scontrol->ipc_control_data. With the change we will allocate [1] amount more memory to be able to hold the full size of data.

In the Linux kernel, the following vulnerability has been resolved: net: qrtr: Drop the MHI auto_queue feature for IPCR DL channels MHI stack offers the 'auto_queue' feature, which allows the MHI stack to auto queue the buffers for the RX path (DL channel). Though this feature simplifies the client driver design, it introduces race between the client drivers and the MHI stack. For instance, with auto_queue, the 'dl_callback' for the DL channel may get called before the client driver is fully probed. This means, by the time the dl_callback gets called, the client driver's structures might not be initialized, leading to NULL ptr dereference. Currently, the drivers have to workaround this issue by initializing the internal structures before calling mhi_prepare_for_transfer_autoqueue(). But even so, there is a chance that the client driver's internal code path may call the MHI queue APIs before mhi_prepare_for_transfer_autoqueue() is called, leading to similar NULL ptr dereference. This issue has been reported on the Qcom X1E80100 CRD machines affecting boot. So to properly fix all these races, drop the MHI 'auto_queue' feature altogether and let the client driver (QRTR) manage the RX buffers manually. In the QRTR driver, queue the RX buffers based on the ring length during probe and recycle the buffers in 'dl_callback' once they are consumed. This also warrants removing the setting of 'auto_queue' flag from controller drivers. Currently, this 'auto_queue' feature is only enabled for IPCR DL channel. So only the QRTR client driver requires the modification.

In the Linux kernel, the following vulnerability has been resolved: rpmsg: core: fix race in driver_override_show() and use core helper The driver_override_show function reads the driver_override string without holding the device_lock. However, the store function modifies and frees the string while holding the device_lock. This creates a race condition where the string can be freed by the store function while being read by the show function, leading to a use-after-free. To fix this, replace the rpmsg_string_attr macro with explicit show and store functions. The new driver_override_store uses the standard driver_set_override helper. Since the introduction of driver_set_override, the comments in include/linux/rpmsg.h have stated that this helper must be used to set or clear driver_override, but the implementation was not updated until now. Because driver_set_override modifies and frees the string while holding the device_lock, the new driver_override_show now correctly holds the device_lock during the read operation to prevent the race. Additionally, since rpmsg_string_attr has only ever been used for driver_override, removing the macro simplifies the code.

In the Linux kernel, the following vulnerability has been resolved: wifi: rtw88: Use devm_kmemdup() in rtw_set_supported_band() Simplify the code by using device managed memory allocations. This also fixes a memory leak in rtw_register_hw(). The supported bands were not freed in the error path. Copied from commit 145df52a8671 ("wifi: rtw89: Convert rtw89_core_set_supported_band to use devm_*").

In the Linux kernel, the following vulnerability has been resolved: most: core: fix resource leak in most_register_interface error paths The function most_register_interface() did not correctly release resources if it failed early (before registering the device). In these cases, it returned an error code immediately, leaking the memory allocated for the interface. Fix this by initializing the device early via device_initialize() and calling put_device() on all error paths. The most_register_interface() is expected to call put_device() on error which frees the resources allocated in the caller. The put_device() either calls release_mdev() or dim2_release(), depending on the caller. Switch to using device_add() instead of device_register() to handle the split initialization.

In the Linux kernel, the following vulnerability has been resolved: hfsplus: ensure sb->s_fs_info is always cleaned up When hfsplus was converted to the new mount api a bug was introduced by changing the allocation pattern of sb->s_fs_info. If setup_bdev_super() fails after a new superblock has been allocated by sget_fc(), but before hfsplus_fill_super() takes ownership of the filesystem-specific s_fs_info data it was leaked. Fix this by freeing sb->s_fs_info in hfsplus_kill_super().

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: annotate data-races around hdev->req_status __hci_cmd_sync_sk() sets hdev->req_status under hdev->req_lock: hdev->req_status = HCI_REQ_PEND; However, several other functions read or write hdev->req_status without holding any lock: - hci_send_cmd_sync() reads req_status in hci_cmd_work (workqueue) - hci_cmd_sync_complete() reads/writes from HCI event completion - hci_cmd_sync_cancel() / hci_cmd_sync_cancel_sync() read/write - hci_abort_conn() reads in connection abort path Since __hci_cmd_sync_sk() runs on hdev->req_workqueue while hci_send_cmd_sync() runs on hdev->workqueue, these are different workqueues that can execute concurrently on different CPUs. The plain C accesses constitute a data race. Add READ_ONCE()/WRITE_ONCE() annotations on all concurrent accesses to hdev->req_status to prevent potential compiler optimizations that could affect correctness (e.g., load fusing in the wait_event condition or store reordering).

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix zero size inode with non-zero size after log replay When logging that an inode exists, as part of logging a new name or logging new dir entries for a directory, we always set the generation of the logged inode item to 0. This is to signal during log replay (in overwrite_item()), that we should not set the i_size since we only logged that an inode exists, so the i_size of the inode in the subvolume tree must be preserved (as when we log new names or that an inode exists, we don't log extents). This works fine except when we have already logged an inode in full mode or it's the first time we are logging an inode created in a past transaction, that inode has a new i_size of 0 and then we log a new name for the inode (due to a new hardlink or a rename), in which case we log an i_size of 0 for the inode and a generation of 0, which causes the log replay code to not update the inode's i_size to 0 (in overwrite_item()). An example scenario: mkdir /mnt/dir xfs_io -f -c "pwrite 0 64K" /mnt/dir/foo sync xfs_io -c "truncate 0" -c "fsync" /mnt/dir/foo ln /mnt/dir/foo /mnt/dir/bar xfs_io -c "fsync" /mnt/dir <power fail> After log replay the file remains with a size of 64K. This is because when we first log the inode, when we fsync file foo, we log its current i_size of 0, and then when we create a hard link we log again the inode in exists mode (LOG_INODE_EXISTS) but we set a generation of 0 for the inode item we add to the log tree, so during log replay overwrite_item() sees that the generation is 0 and i_size is 0 so we skip updating the inode's i_size from 64K to 0. Fix this by making sure at fill_inode_item() we always log the real generation of the inode if it was logged in the current transaction with the i_size we logged before. Also if an inode created in a previous transaction is logged in exists mode only, make sure we log the i_size stored in the inode item located from the commit root, so that if we log multiple times that the inode exists we get the correct i_size. A test case for fstests will follow soon.