From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793831485; b=hAKYUkDdU5WUl1jujZqNm39g8eoR+SCknhBEIaRZ+hoL9Z3FwXA5ZEM7k/+/9n4EikgG pUqrE4ndkuX2Fa16SSnIYl/TyZbUYhFlq0A+ckh4JHuNiW93EDCV+cwg1VJcxNmncXUpo fL2Klh1uaW4+Y+INfDb2WuL23X75pyaXAk7yDbJVFAB3/lMovx2BciEZ3+Z2rZ8gW1UKa 54t6qaWkKzo1X+g1w6o2uygIsQFK5NHS3cJvmqIUccYeV0xrQHAq7qwpF6WJdRmY7Lp6d 0vt7M45lGIGuPqnjuSKqIHwDX3JFCWvbbTm8hM/dErMjgaMN+jvF1daxwsr5bxaO/3Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793831485; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=r/Fzi+K1DHOPipX7vhZDahErcgwWjefDVrmzcH4xmXs=; b=332kl2VdAdpI2eMdQVETYzKSs6EyV1FdkVe3gA5MhQFa28Y6LSD9/6Hb94KZv3oYMprU Pf8/0RP2+1ndD6/xANdFq2Ov0V6+sU25jSfdkAH5QWTDXATUQvFYYDLHq7DzjW6J4kuCK 8pI3Slu/Fmer3991odqTp2+2/YyZje+vBi3M2LrSAzT0GUM18lZNFtZH9jMa5LgmNNrDF 0oPWO7q1jt6Try8nTLX+dX72be7sSW7q4fO6WLoBMTtfO4n+NZ1eFSzqv/ggfGn+r5nB6 ZYD7x+fjZytZAB4hDSYf7JsEjk1igfJw2B4smCrpmcjxuiCVLSP5fgGi4dAw6uK/ubg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=p4j8wgqz; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0F763606B2DC; Wed, 4 Nov 2026 22:31:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=p4j8wgqz Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9D1031F000C1; Wed, 4 Nov 2026 22:31:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793831484; bh=r/Fzi+K1DHOPipX7vhZDahErcgwWjefDVrmzcH4xmXs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=p4j8wgqzHRS9f3Ww3LDqjtPA0ylUZPKhV/w/KpIdfeLuzOTWmXwYKuXvUuKWdFy7w 1Nt29KkEfTysUnvRRyx9s60/iHyScY14FVDxN998ldlQ80TnF25dejqjQ3CrUyk90W FIXlwy7m/ykTcwwPey4OKrlhevYi9YUbtwtPI6Qk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Richard Patel , Thomas Gleixner Subject: [PATCH 6.18 0715/1005] genirq: Move interrupt thread exit_work object to irqaction Date: Wed, 4 Nov 2026 16:07:28 -0500 Message-ID: <20261104211103.571491519@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-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 @@ -118,6 +118,7 @@ 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; @@ -133,6 +134,7 @@ 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 @@ -1198,9 +1198,9 @@ 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); @@ -1247,7 +1247,6 @@ 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, @@ -1264,8 +1263,8 @@ 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;