CVE-2026-98357 - IB/isert: wait for deferred control PDU completions before releasing the connection
CVE ID :CVE-2026-98357
Published : Oct. 6, 2026, 9:18 a.m. | 2 hours, 27 minutes ago
Description :In the Linux kernel, the following vulnerability has been resolved: IB/isert: wait for deferred control PDU completions before releasing the connection isert_send_done() hands ISTATE_SEND_TASKMGTRSP, ISTATE_SEND_REJECT and ISTATE_SEND_TEXTRSP completions off to isert_comp_wq and returns. The work item then runs isert_completion_put() -> isert_put_cmd(), which reads isert_conn->conn and takes conn->cmd_lock. Nothing orders that work item against teardown. isert_wait_conn() queues isert_release_work, which frees isert_conn, and iscsit_close_connection() frees the iscsit_conn right after it returns, so the queued work can run against freed memory. Count the deferred control PDU completions per connection and let isert_wait_conn() wait for them before the release work is queued. ISTATE_SEND_LOGOUTRSP is deliberately not counted: that branch runs iscsit_logout_post_handler(), which ends up waiting for conn->conn_wait_comp, and that completion is only sent by iscsit_close_connection() after it has called iscsit_wait_conn(). Waiting for it here would deadlock. Its wait stays the existing isert_wait4logout(). The splat below is from a kernel with tracing printk()s and an msleep(200) injected into isert_do_control_comp() to widen the window: BUG: KASAN: slab-use-after-free in isert_put_cmd+0x53d/0x620 Read of size 8 at addr ffff8881054f1038 by task kworker/u17:1/182 CPU: 0 UID: 0 PID: 182 Comm: kworker/u17:1 Tainted: G B 7.2.0-rc5-TWIDE-gb8babf08acc7 #1 PREEMPT(lazy) Tainted: [B]=BAD_PAGE Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Workqueue: isert_comp_wq isert_do_control_comp Call Trace:
dump_stack_lvl+0x53/0x70
print_report+0xd0/0x630
? __pfx__raw_spin_lock_irqsave+0x10/0x10
? _raw_spin_unlock_irqrestore+0x3e/0x70
? isert_put_cmd+0x53d/0x620
kasan_report+0xce/0x100
? isert_put_cmd+0x53d/0x620
isert_put_cmd+0x53d/0x620
? isert_completion_put+0x305/0x330
? isert_do_control_comp+0x2ef/0x310
process_one_work+0x633/0x1030
? assign_work+0x11d/0x370
worker_thread+0x45b/0xd10
? __pfx_worker_thread+0x10/0x10
? __pfx_worker_thread+0x10/0x10
kthread+0x2c6/0x3b0
? recalc_sigpending+0x15c/0x1e0
? __pfx_kthread+0x10/0x10
ret_from_fork+0x36e/0x5a0
? __pfx_ret_from_fork+0x10/0x10
? __switch_to+0x572/0xdd0
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
Allocated by task 48:
kasan_save_stack+0x33/0x60
kasan_save_track+0x14/0x30
__kasan_kmalloc+0x8f/0xa0
__kmalloc_cache_noprof+0x158/0x370
isert_cma_handler+0x1e3/0x2ae0
cma_cm_event_handler+0x3e/0x240
cma_ib_req_handler+0x17d9/0x4490
cm_process_work+0x41/0x330
cm_work_handler+0x5727/0xc160
process_one_work+0x633/0x1030
worker_thread+0x45b/0xd10
kthread+0x2c6/0x3b0
ret_from_fork+0x36e/0x5a0
ret_from_fork_asm+0x1a/0x30
Freed by task 184:
kasan_save_stack+0x33/0x60
kasan_save_track+0x14/0x30
kasan_save_free_info+0x3b/0x60
__kasan_slab_free+0x43/0x70
kfree+0x121/0x380
iscsit_close_connection+0x7cf/0x1e60
iscsit_take_action_for_connection_exit+0x1b6/0x360
iscsi_target_tx_thread+0x472/0x690
kthread+0x2c6/0x3b0
ret_from_fork+0x36e/0x5a0
ret_from_fork_asm+0x1a/0x30
Severity: 0.0 | NA
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Published : Oct. 6, 2026, 9:18 a.m. | 2 hours, 27 minutes ago
Description :In the Linux kernel, the following vulnerability has been resolved: IB/isert: wait for deferred control PDU completions before releasing the connection isert_send_done() hands ISTATE_SEND_TASKMGTRSP, ISTATE_SEND_REJECT and ISTATE_SEND_TEXTRSP completions off to isert_comp_wq and returns. The work item then runs isert_completion_put() -> isert_put_cmd(), which reads isert_conn->conn and takes conn->cmd_lock. Nothing orders that work item against teardown. isert_wait_conn() queues isert_release_work, which frees isert_conn, and iscsit_close_connection() frees the iscsit_conn right after it returns, so the queued work can run against freed memory. Count the deferred control PDU completions per connection and let isert_wait_conn() wait for them before the release work is queued. ISTATE_SEND_LOGOUTRSP is deliberately not counted: that branch runs iscsit_logout_post_handler(), which ends up waiting for conn->conn_wait_comp, and that completion is only sent by iscsit_close_connection() after it has called iscsit_wait_conn(). Waiting for it here would deadlock. Its wait stays the existing isert_wait4logout(). The splat below is from a kernel with tracing printk()s and an msleep(200) injected into isert_do_control_comp() to widen the window: BUG: KASAN: slab-use-after-free in isert_put_cmd+0x53d/0x620 Read of size 8 at addr ffff8881054f1038 by task kworker/u17:1/182 CPU: 0 UID: 0 PID: 182 Comm: kworker/u17:1 Tainted: G B 7.2.0-rc5-TWIDE-gb8babf08acc7 #1 PREEMPT(lazy) Tainted: [B]=BAD_PAGE Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Workqueue: isert_comp_wq isert_do_control_comp Call Trace:
Severity: 0.0 | NA
Visit the link for more details, such as CVSS details, affected products, timeline, and more...