7.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Richard Patel commit 89a9e003a2ef73f67dff03dfd59e0a5474b56b0b upstream. irq_thread() registers irq_thread_dtor() as exit task_work using a stack-allocated callback_head. On normal interrupt thread exit, this work gets cancelled and never runs. On x86, an abnormal interrupt thread exit (e.g. handler oops) discards the stack, including the callback_head, while that callback_head is still pending. By the time exit_task_work() runs, the stack memory formerly backing callback_head is already clobbered. irq_thread() <-- on_exit_work allocated ** IRQ handler faults ** oops_end() rewind_stack_and_make_dead() <-- on_exit_work freed make_task_dead() do_exit(SIGSEGV) ... exit_shm() <-- on_exit_work clobbered ... exit_task_work() <-- stack use-after-free exit_shm()+0x30 <-- wild jump to return addr Thus, a benign threaded IRQ oops (e.g. a NULL pointer deref) is turned into a wild jump. This is caught by kernel IBT: ** first fault ** Oops: general protection fault, kernel NULL pointer dereference 0x3c0: 0000 [#1] SMP NOPTI ... ** second fault ** Missing ENDBR: exit_shm+0x30/0x1c0 kernel BUG at arch/x86/kernel/cet.c:133! ... ? task_work_run+0x5c/0x90 ? do_exit+0x209/0x460 ? rewind_stack_and_make_dead+0x16/0x20 ... note: irq/165-AudioDS[1427] exited with irqs disabled Fixing recursive fault but reboot is needed! Fix this by storing the callback_head in struct irqaction. The irqaction is only freed once irq_thread_dtor() finishes. Fixes: 2deb4be28077 ("x86/dumpstack: When OOPSing, rewind the stack before do_exit()") Signed-off-by: Richard Patel Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20261009145842.1616117-3-ripatel@wii.dev Signed-off-by: Greg Kroah-Hartman --- include/linux/interrupt.h | 2 ++ kernel/irq/manage.c | 9 ++++----- 2 files changed, 6 insertions(+), 5 deletions(-) --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -119,6 +119,7 @@ typedef irqreturn_t (*irq_handler_t)(int * @thread_flags: flags related to @thread * @thread_mask: bitmask for keeping track of @thread activity * @dir: pointer to the proc/irq/NN/name entry + * @thread_dtor: task_work for @thread irregular exit cleanup */ struct irqaction { irq_handler_t handler; @@ -137,6 +138,7 @@ struct irqaction { unsigned long thread_mask; const char *name; struct proc_dir_entry *dir; + struct callback_head thread_dtor; } ____cacheline_internodealigned_in_smp; extern irqreturn_t no_action(int cpl, void *dev_id); --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -1201,9 +1201,9 @@ static void __irq_thread_dtor(struct irq irq_finalize_oneshot(desc, action); } -static void irq_thread_dtor(struct callback_head *unused) +static void irq_thread_dtor(struct callback_head *work) { - struct irqaction *action = kthread_data(current); + struct irqaction *action = container_of(work, struct irqaction, thread_dtor); __irq_thread_dtor(action); clear_and_wake_up_bit(IRQTF_EXIT_WORK, &action->thread_flags); @@ -1250,7 +1250,6 @@ static void wake_up_and_wait_for_irq_thr */ static int irq_thread(void *data) { - struct callback_head on_exit_work; struct irqaction *action = data; struct irq_desc *desc = irq_to_desc(action->irq); irqreturn_t (*handler_fn)(struct irq_desc *desc, @@ -1270,8 +1269,8 @@ static int irq_thread(void *data) handler_fn = irq_thread_fn; set_bit(IRQTF_EXIT_WORK, &action->thread_flags); - init_task_work(&on_exit_work, irq_thread_dtor); - task_work_add(current, &on_exit_work, TWA_NONE); + init_task_work(&action->thread_dtor, irq_thread_dtor); + task_work_add(current, &action->thread_dtor, TWA_NONE); while (!irq_wait_for_interrupt(desc, action)) { irqreturn_t action_ret;