NULL Pointer Dereference

In the Linux kernel, the following vulnerability has been resolved: firmware: stratix10-rsu: Fix NULL deref on rsu_send_msg() timeout in probe rsu_send_msg() can return -ETIMEDOUT when wait_for_completion_interruptible_timeout() fires while the SMC call is still pending. In stratix10_rsu_probe(), the error paths for COMMAND_RSU_DCMF_VERSION, COMMAND_RSU_DCMF_STATUS, COMMAND_RSU_MAX_RETRY and COMMAND_RSU_GET_SPT_TABLE call stratix10_svc_free_channel() - which sets chan->scl to NULL - but then fall through and queue the next request on the same channel. The next svc kthread that runs will dereference pdata->chan->scl in its receive callback path, triggering a NULL pointer dereference identical to the one fixed by commit c45f7263100c ("firmware: stratix10-rsu: Fix NULL pointer dereference when RSU is disabled") for the COMMAND_RSU_STATUS path. Apply the same cleanup pattern to the remaining failure paths: remove the async client, free the channel, and return early so no further messages are queued on a channel whose scl has been cleared. While at it, clean up stratix10_rsu_probe() in two ways without changing behavior: - Drop redundant zero-initialization of fields already cleared by devm_kzalloc(): client.receive_cb, status.* and spt0/1_address (INVALID_SPT_ADDRESS is 0x0). - Replace five identical 3-line error-cleanup blocks (stratix10_svc_remove_async_client() + stratix10_svc_free_channel() + return ret) with goto labels (remove_async_client, free_channel), matching the standard kernel resource-unwinding pattern and making it easier to extend the probe sequence without forgetting matching cleanup. Also move init_completion() next to mutex_init() so sync-primitive initialization is grouped before anything that could trigger a callback. --- v2: Add a minor clean-up of the function stratix10_rsu_probe() to have a centralize exit for all the rsu_send_async_msg() and rsu_send_msg().Show less

In the Linux kernel, the following vulnerability has been resolved: bnxt_en: Fix NULL pointer dereference PCIe errors detected by a Root Port or Downstream Port cause error recovery services to run on all subordinate devices regardless of administrative state. The .error_detected() callback, bnxt_io_error_detected(), disables and synchronizes IRQs via bnxt_disable_int_sync(), which calls bnxt_cp_num_to_irq_num() to map completion rings to IRQs using bp->bnapi. Since bp->bnapi is allocated on NIC open and freed on NIC close, PCIe error recovery on a closed NIC can dereference a NULL pointer. Check if bp->bnapi is NULL before disabling and synchronizing IRQs.Show less

In the Linux kernel, the following vulnerability has been resolved: iomap: avoid potential null folio->mapping deref during error reporting When a buffered read fails, iomap_finish_folio_read() reports the error with fserror_report_io(folio->mapping->host, ...). This is called after ifs->read_bytes_pending has been decremented by the bytes attempted to be read. For a folio split across multiple read completions, the folio is only guaranteed to stay locked while read_bytes_pending > 0. Once iomap_finish_folio_read() decrements read_bytes_pending, another in-flight read can complete and end the read on the folio, which unlocks it. This allows truncate logic to run and detach the folio (set folio->mapping to NULL). The error reporting path then can dereference a NULL folio->mapping. As reported by Sam Sun, this is the race that can occur: CPU0: failed completion CPU1: final completion CPU2: truncate ----------------------- ---------------------- -------------- read_bytes_pending -= len finished = false /* preempted before fserror_report_io() */ read_bytes_pending -= len finished = true folio_end_read() truncate clears folio->mapping fserror_report_io( folio->mapping->host, ...) ^ NULL deref Fix this by reporting the error first before decrementing ifs->read_bytes_pending.Show less

In the Linux kernel, the following vulnerability has been resolved: locking/rtmutex: Skip remove_waiter() when waiter is not enqueued syzbot triggered the following splat in remove_waiter() via FUTEX_CMP_REQUEUE_PI: KASAN: null-ptr-deref in range [0x0000000000000a88-0x0000000000000a8f] class_raw_spinlock_constructor remove_waiter+0x159/0x1200 kernel/locking/rtmutex.c:1561 rt_mutex_start_proxy_lock+0x103/0x120 futex_requeue+0x10e4/0x20d0 __x64_sys_futex+0x34f/0x4d0 task_blocks_on_rt_mutex() does not arm the waiter upon deadlock detection, leaving waiter->task nil, where 3bfdc63936dd ("rtmutex: Use waiter::task instead of current in remove_waiter()") made this fatal. Furthermore, rt_mutex_start_proxy_lock() should not be calling into remove_waiter() upon a successfully grabbing the rtmutex. 1a1fb985f2e2 ("futex: Handle early deadlock return correctly"), moved the remove_waiter() out of __rt_mutex_start_proxy_lock() (where 'ret' was only ever 0 or < 0) into the wrapper. Tighten this check to account for try_to_take_rt_mutex().Show less

In the Linux kernel, the following vulnerability has been resolved: misc: fastrpc: Fix NULL pointer dereference in rpmsg callback A NULL pointer dereference was observed on Hawi at boot when the DSP sends a glink message before fastrpc_rpmsg_probe() has completed initialization: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000178 pc : _raw_spin_lock_irqsave+0x34/0x8c lr : fastrpc_rpmsg_callback+0x3c/0xcc [fastrpc] ... Call trace: _raw_spin_lock_irqsave+0x34/0x8c (P) fastrpc_rpmsg_callback+0x3c/0xcc [fastrpc] qcom_glink_native_rx+0x538/0x6a4 qcom_glink_smem_intr+0x14/0x24 [qcom_glink_smem] The faulting address 0x178 corresponds to the lock variable inside struct fastrpc_channel_ctx, confirming that cctx is NULL when fastrpc_rpmsg_callback() attempts to take the spinlock. There are two issues here. First, dev_set_drvdata() is called before spin_lock_init() and idr_init(), leaving a window where the callback can retrieve a valid cctx pointer but operate on an uninitialized spinlock. Second, the rpmsg channel becomes live as soon as the driver is bound, so fastrpc_rpmsg_callback() can fire before dev_set_drvdata() is called at all, resulting in dev_get_drvdata() returning NULL. Fix both issues by moving all cctx initialization ahead of dev_set_drvdata() so the structure is fully initialized before it becomes visible to the callback, and add a NULL check in fastrpc_rpmsg_callback() as a guard against any remaining window.Show less

In the Linux kernel, the following vulnerability has been resolved: mmc: dw_mmc-rockchip: Add missing private data for very old controllers The really old controllers (rk2928, rk3066, rk3188) do not support UHS speeds at all, and thus never handled phase data. For that reason it never had a parse_dt callback and no driver private data at all. Commit ff6f0286c896 ("mmc: dw_mmc-rockchip: Add memory clock auto-gating support") makes the private data sort of mandatory, because the init function checks whether phases are configured internally or through the clock controller. This results in the old SoCs then experiencing NULL-pointer dereferences when they try to access that private-data struct. While we could have if (priv) conditionals in all places, it's way less cluttery to just give the old types their private-data struct.Show less

In the Linux kernel, the following vulnerability has been resolved: drm/amdkfd: fix NULL dereference in get_queue_ids() When usr_queue_id_array is NULL and num_queues is non-zero, get_queue_ids() returns NULL. The callers check only IS_ERR() on the return value; since IS_ERR(NULL) == false the check passes, and suspend_queues() calls q_array_invalidate() which immediately dereferences NULL while iterating num_queues times. Userspace can trigger this via kfd_ioctl_set_debug_trap() by supplying num_queues > 0 with a zero queue_array_ptr, causing a kernel panic. A NULL usr_queue_id_array with num_queues == 0 is a legitimate no-op (q_array_invalidate never executes, and resume_queues already guards all queue_ids dereferences behind a NULL check). Return ERR_PTR(-EINVAL) only when num_queues is non-zero and the pointer is absent; both callers already propagate IS_ERR() returns correctly to userspace. (cherry picked from commit f165a82cdf503884bb1797771c61b2fcc72113d4)Show less

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Fix NULL deref and buffer over-read in SDP debugfs [Why & How] dp_sdp_message_debugfs_write() dereferences connector->base.state->crtc without checking for NULL. A connector can be connected but not bound to any CRTC (e.g. after hot-plug before the next atomic commit), causing a kernel crash when writing to the sdp_message debugfs node. The function also ignores the user-provided size argument and always passes 36 bytes to copy_from_user(), reading past the user buffer when size < 36. Fix both issues by: - Returning -ENODEV when connector->base.state or state->crtc is NULL - Clamping write_size to min(size, sizeof(data)) (cherry picked from commit 6ab4c36a522842ff70474a1c0af2e40e50fc8300)Show less

In the Linux kernel, the following vulnerability has been resolved: bpf: Use RCU-safe iteration in dev_map_redirect_multi() SKB path The DEVMAP_HASH branch in dev_map_redirect_multi() uses hlist_for_each_entry_safe() to iterate hash buckets, but this function runs under RCU protection (called from xdp_do_generic_redirect_map() in softirq context). Concurrent writers (__dev_map_hash_update_elem, dev_map_hash_delete_elem) modify the list using RCU primitives (hlist_add_head_rcu, hlist_del_rcu). hlist_for_each_entry_safe() performs plain pointer dereferences without rcu_dereference(), missing the acquire barrier needed to pair with writers' rcu_assign_pointer(). On weakly-ordered architectures (ARM64, POWER), a reader can observe a partially-constructed node. It also defeats CONFIG_PROVE_RCU lockdep validation and KCSAN data-race detection. Replace with hlist_for_each_entry_rcu() using rcu_read_lock_bh_held() as the lockdep condition, consistent with the rcu_dereference_check() used in the DEVMAP (non-hash) branch of the same functions. Also fix the same incorrect lockdep_is_held(&dtab->index_lock) condition in dev_map_enqueue_multi(), where the lock is not held either.Show less

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_ldisc: Clear HCI_UART_PROTO_INIT on error When hci_register_dev() fails in hci_uart_register_dev() HCI_UART_PROTO_INIT is not cleared before calling hu->proto->close(hu) and setting hu->hdev to NULL. This means incoming UART data will reach the protocol-specific recv handler in hci_uart_tty_receive() after resources are freed. Clear HCI_UART_PROTO_INIT with a write lock before calling hu->proto->close() and setting hu->hdev to NULL. The write lock ensures all active readers have completed and no new reader can enter the protocol recv path before resources are freed. This allows the protocol-specific recv functions to remove the "HCI_UART_REGISTERED" guard without risking a null pointer dereference if hci_register_dev() fails.Show less

In the Linux kernel, the following vulnerability has been resolved: net, bpf: fix null-ptr-deref in xdp_master_redirect() for down master syzkaller reported a kernel panic in bond_rr_gen_slave_id() reached via xdp_master_redirect(). Full decoded trace: https://syzkaller.appspot.com/bug?extid=80e046b8da2820b6ba73 bond_rr_gen_slave_id() dereferences bond->rr_tx_counter, a per-CPU counter that bonding only allocates in bond_open() when the mode is round-robin. If the bond device was never brought up, rr_tx_counter stays NULL. The XDP redirect path can still reach that code on a bond that was never opened: bpf_master_redirect_enabled_key is a global static key, so as soon as any bond device has native XDP attached, the XDP_TX -> xdp_master_redirect() interception is enabled for every slave system-wide. The path xdp_master_redirect() -> bond_xdp_get_xmit_slave() -> bond_xdp_xmit_roundrobin_slave_get() -> bond_rr_gen_slave_id() then runs against a bond that has no rr_tx_counter and crashes. Fix this in the generic xdp_master_redirect() by refusing to call into the master's ->ndo_xdp_get_xmit_slave() when the master device is not up. IFF_UP is only set after ->ndo_open() has successfully returned, so this reliably excludes masters whose XDP state has not been fully initialized. Drop the frame with XDP_ABORTED so the exception is visible via trace_xdp_exception() rather than silently falling through. This is not specific to bonding: any current or future master that defers XDP state allocation to ->ndo_open() is protected.Show less

In the Linux kernel, the following vulnerability has been resolved: drm/sun4i: backend: fix error pointer dereference The function drm_atomic_get_plane_state() can return an error pointer and is not checked for it. Add error pointer check. Detected by Smatch: drivers/gpu/drm/sun4i/sun4i_backend.c:496 sun4i_backend_atomic_check() error: 'plane_state' dereferencing possible ERR_PTR()Show less

In the Linux kernel, the following vulnerability has been resolved: dm cache: fix null-deref with concurrent writes in passthrough mode In passthrough mode, when dm-cache starts to invalidate a cache entry and bio prison cell lock fails due to concurrent write to the same cached block, mg->cell remains NULL. The error path in invalidate_complete() attempts to unlock and free the cell unconditionally, causing a NULL pointer dereference: KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 UID: 0 PID: 134 Comm: fio Not tainted 6.19.0-rc7 #3 PREEMPT RIP: 0010:dm_cell_unlock_v2+0x3f/0x210 <snip> Call Trace: invalidate_complete+0xef/0x430 map_bio+0x130f/0x1a10 cache_map+0x320/0x6b0 __map_bio+0x458/0x510 dm_submit_bio+0x40e/0x16d0 __submit_bio+0x419/0x870 <snip> Reproduce steps: 1. Create a cache device dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" dmsetup create cdata --table "0 131072 linear /dev/sdc 8192" dmsetup create corig --table "0 262144 linear /dev/sdc 262144" dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct dmsetup create cache --table "0 262144 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" 2. Promote the first data block into cache fio --filename=/dev/mapper/cache --name=populate --rw=write --bs=4k \ --direct=1 --size=64k 3. Reload the cache into passthrough mode dmsetup suspend cache dmsetup reload cache --table "0 262144 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 passthrough smq 0" dmsetup resume cache 4. Write to the first cached block concurrently fio --filename=/dev/mapper/cache --name test --rw=randwrite --bs=4k \ --randrepeat=0 --direct=1 --numjobs=2 --size 64k Fix by checking if mg->cell is valid before attempting to unlock it.Show less

In the Linux kernel, the following vulnerability has been resolved: drm/bridge: cadence: cdns-mhdp8546-core: Set the mhdp connector earlier in atomic_enable() In case if we get errors in cdns_mhdp_link_up() or cdns_mhdp_reg_read() in atomic_enable, we will go to cdns_mhdp_modeset_retry_fn() and will hit NULL pointer while trying to access the mutex. We need the connector to be set before that. Unlike in legacy cases with flag !DRM_BRIDGE_ATTACH_NO_CONNECTOR, we do not have connector initialised in bridge_attach(), so add the mhdp->connector_ptr in device structure to handle both cases with DRM_BRIDGE_ATTACH_NO_CONNECTOR and !DRM_BRIDGE_ATTACH_NO_CONNECTOR, set it in atomic_enable() earlier to avoid possible NULL pointer dereference in recovery paths like modeset_retry_fn() with the DRM_BRIDGE_ATTACH_NO_CONNECTOR flag set.Show less

In the Linux kernel, the following vulnerability has been resolved: gfs2: prevent NULL pointer dereference during unmount When flushing out outstanding glock work during an unmount, gfs2_log_flush() can be called when sdp->sd_jdesc has already been deallocated and sdp->sd_jdesc is NULL. Commit 35264909e9d1 ("gfs2: Fix NULL pointer dereference in gfs2_log_flush") added a check for that to gfs2_log_flush() itself, but it missed the sdp->sd_jdesc dereference in gfs2_log_release(). Fix that.Show less

In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: Fix af_unix null-ptr-deref in proto update unix_stream_connect() sets sk_state (`WRITE_ONCE(sk->sk_state, TCP_ESTABLISHED)`) _before_ it assigns a peer (`unix_peer(sk) = newsk`). sk_state == TCP_ESTABLISHED makes sock_map_sk_state_allowed() believe that socket is properly set up, which would include having a defined peer. IOW, there's a window when unix_stream_bpf_update_proto() can be called on socket which still has unix_peer(sk) == NULL. CPU0 bpf CPU1 connect -------- ------------ WRITE_ONCE(sk->sk_state, TCP_ESTABLISHED) sock_map_sk_state_allowed(sk) ... sk_pair = unix_peer(sk) sock_hold(sk_pair) sock_hold(newsk) smp_mb__after_atomic() unix_peer(sk) = newsk BUG: kernel NULL pointer dereference, address: 0000000000000080 RIP: 0010:unix_stream_bpf_update_proto+0xa0/0x1b0 Call Trace: sock_map_link+0x564/0x8b0 sock_map_update_common+0x6e/0x340 sock_map_update_elem_sys+0x17d/0x240 __sys_bpf+0x26db/0x3250 __x64_sys_bpf+0x21/0x30 do_syscall_64+0x6b/0x3a0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Initial idea was to move peer assignment _before_ the sk_state update[1], but that involved an additional memory barrier, and changing the hot path was rejected. Then a NULL check during proto update in unix_stream_bpf_update_proto() was considered[2], but the follow-up discussion[3] focused on the root cause, i.e. sockmap update taking a wrong lock. Or, more specifically, missing unix_state_lock()[4]. In the end it was concluded that teaching sockmap about the af_unix locking would be unnecessarily complex[5]. Complexity aside, since BPF_PROG_TYPE_SCHED_CLS and BPF_PROG_TYPE_SCHED_ACT are allowed to update sockmaps, sock_map_update_elem() taking the unix lock, as it is currently implemented in unix_state_lock(): spin_lock(&unix_sk(s)->lock), would be problematic. unix_state_lock() taken in a process context, followed by a softirq-context TC BPF program attempting to take the same spinlock -- deadlock[6]. This way we circled back to the peer check idea[2]. [1]: https://lore.kernel.org/netdev/ba5c50aa-1df4-40c2-ab33-a72022c5a32e@rbox.co/ [2]: https://lore.kernel.org/netdev/20240610174906.32921-1-kuniyu@amazon.com/ [3]: https://lore.kernel.org/netdev/7603c0e6-cd5b-452b-b710-73b64bd9de26@linux.dev/ [4]: https://lore.kernel.org/netdev/CAAVpQUA+8GL_j63CaKb8hbxoL21izD58yr1NvhOhU=j+35+3og@mail.gmail.com/ [5]: https://lore.kernel.org/bpf/CAAVpQUAHijOMext28Gi10dSLuMzGYh+jK61Ujn+fZ-wvcODR2A@mail.gmail.com/ [6]: https://lore.kernel.org/bpf/dd043c69-4d03-46fe-8325-8f97101435cf@linux.dev/ Summary of scenarios where af_unix/stream connect() may race a sockmap update: 1. connect() vs. bpf(BPF_MAP_UPDATE_ELEM), i.e. sock_map_update_elem_sys() Implemented NULL check is sufficient. Once assigned, socket peer won't be released until socket fd is released. And that's not an issue because sock_map_update_elem_sys() bumps fd refcnf. 2. connect() vs BPF program doing update Update restricted per verifier.c:may_update_sockmap() to BPF_PROG_TYPE_TRACING/BPF_TRACE_ITER BPF_PROG_TYPE_SOCK_OPS (bpf_sock_map_update() only) BPF_PROG_TYPE_SOCKET_FILTER BPF_PROG_TYPE_SCHED_CLS BPF_PROG_TYPE_SCHED_ACT BPF_PROG_TYPE_XDP BPF_PROG_TYPE_SK_REUSEPORT BPF_PROG_TYPE_FLOW_DISSECTOR BPF_PROG_TYPE_SK_LOOKUP Plus one more race to consider: CPU0 bpf CPU1 connect -------- ------------ WRITE_ONCE(sk->sk_state, TCP_ESTABLISHED) sock_map_sk_state_allowed(sk) sock_hold(newsk) smp_mb__after_atomic() ---truncated---Show less

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix NULL deref in map_kptr_match_type for scalar regs Commit ab6c637ad027 ("bpf: Fix a bpf_kptr_xchg() issue with local kptr") refactored map_kptr_match_type() to branch on btf_is_kernel() before checking base_type(). A scalar register stored into a kptr slot has no btf, so the btf_is_kernel(reg->btf) call dereferences NULL. Move the base_type() != PTR_TO_BTF_ID guard before any reg->btf access.Show less

In the Linux kernel, the following vulnerability has been resolved: usb: typec: Fix error pointer dereference The variable tps->partner is checked for an error pointer and then if it is, it sends an error message but does not return and then immediately dereferenced a few lines below: tps->partner = typec_register_partner(tps->port, &desc); if (IS_ERR(tps->partner)) dev_warn(tps->dev, "%s: failed to register partnet\n", __func__); if (desc.identity) { typec_partner_set_identity(tps->partner); cd321x->cur_partner_identity = st.partner_identity; } Add early return and fix spelling mistake in error message. Detected by Smatch: drivers/usb/typec/tipd/core.c:827 cd321x_update_work() error: 'tps->partner' dereferencing possible ERR_PTR()Show less