Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934893AbcJQMid (ORCPT ); Mon, 17 Oct 2016 08:38:33 -0400 Received: from mail-qt0-f193.google.com ([209.85.216.193]:34693 "EHLO mail-qt0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934860AbcJQMiR (ORCPT ); Mon, 17 Oct 2016 08:38:17 -0400 From: Corentin Labbe To: a.zummo@towertech.it, alexandre.belloni@free-electrons.com Cc: rtc-linux@googlegroups.com, linux-kernel@vger.kernel.org, Corentin Labbe Subject: [PATCH] rtc: cmos: remove all __exit_p annotations Date: Mon, 17 Oct 2016 14:36:03 +0200 Message-Id: <1476707763-9222-1-git-send-email-clabbe.montjoie@gmail.com> X-Mailer: git-send-email 2.7.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5159 Lines: 119 I got the following stack trace under qemu: [ 7.575243] BUG: unable to handle kernel NULL pointer dereference at 0000000000000010 [ 7.596098] IP: [] cmos_set_alarm+0x38/0x280 [ 7.615699] PGD 3ccbe067 [ 7.615923] PUD 3daf2067 [ 7.635156] PMD 0 [ 7.654358] Oops: 0000 [#1] SMP [ 7.673869] Modules linked in: [ 7.693235] CPU: 0 PID: 1701 Comm: hwclock Tainted: G W 4.9.0-rc1+ #24 [ 7.712455] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014 [ 7.753569] task: ffff88003d88dc40 task.stack: ffffc90000224000 [ 7.773743] RIP: 0010:[] [] cmos_set_alarm+0x38/0x280 [ 7.794893] RSP: 0018:ffffc90000227c10 EFLAGS: 00010296 [ 7.815890] RAX: 000000000000001d RBX: ffffc90000227d28 RCX: ffffffff8182be78 [ 7.836057] RDX: 0000000000000001 RSI: 0000000000000202 RDI: 0000000000000202 [ 7.856612] RBP: ffffc90000227c48 R08: 0000000000000000 R09: 0000000000000001 [ 7.877561] R10: 00000000000001c0 R11: 00000000000001c0 R12: 0000000000000000 [ 7.897072] R13: ffff88003d96f400 R14: ffff88003dac6410 R15: ffff88003dac6420 [ 7.917403] FS: 00007f77f42d9700(0000) GS:ffff88003fc00000(0000) knlGS:0000000000000000 [ 7.938293] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 7.958364] CR2: 0000000000000010 CR3: 000000003ccbb000 CR4: 00000000000006f0 [ 7.978028] Stack: [ 7.997120] ffff88003dac6000 ffff88003dac6410 0000000058049d01 ffffc90000227d28 [ 8.016993] ffff88003dac6000 ffff88003dac6410 ffff88003dac6420 ffffc90000227c98 [ 8.039505] ffffffff814f225d 0000001800227c98 000000090000002a 0000000900000011 [ 8.059985] Call Trace: [ 8.080110] [] __rtc_set_alarm+0x8d/0xa0 [ 8.099421] [] rtc_timer_enqueue+0x119/0x190 [ 8.119925] [] rtc_update_irq_enable+0xbe/0x100 [ 8.140583] [] rtc_dev_ioctl+0x3c0/0x480 [ 8.161162] [] ? user_path_at_empty+0x3a/0x50 [ 8.182717] [] do_vfs_ioctl+0x96/0x5c0 [ 8.204624] [] ? vfs_stat+0x16/0x20 [ 8.225994] [] ? SyS_newstat+0x15/0x30 [ 8.247043] [] SyS_ioctl+0x47/0x80 [ 8.267191] [] entry_SYSCALL_64_fastpath+0x1a/0xa9 [ 8.288719] Code: 6a 81 48 89 e5 41 57 41 56 41 55 49 89 fd 41 54 53 48 89 f3 48 c7 c6 20 c4 78 81 48 83 ec 10 e8 8f 00 ef ff 4d 8b a5 a0 00 00 00 <41> 8b 44 24 10 85 c0 0f 8e 2b 02 00 00 4c 89 ef 31 c0 b9 53 01 [ 8.335233] RIP [] cmos_set_alarm+0x38/0x280 [ 8.357096] RSP [ 8.379051] CR2: 0000000000000010 [ 8.401736] ---[ end trace 5cbcd83a1f225ed3 ]--- This occur only when CONFIG_DEBUG_TEST_DRIVER_REMOVE is enabled and CONFIG_RTC_DRV_CMOS builtin. When cmos_set_alarm() is called dev is NULL and so trigger the deref via cmos->irq The problem comes from that the device is removed but no remove function are called due to _exit_p(). This patch remove all _exit_p() annotation. Signed-off-by: Corentin Labbe --- drivers/rtc/rtc-cmos.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c index dd3d598..b1f3d64 100644 --- a/drivers/rtc/rtc-cmos.c +++ b/drivers/rtc/rtc-cmos.c @@ -776,7 +776,7 @@ static void cmos_do_shutdown(int rtc_irq) spin_unlock_irq(&rtc_lock); } -static void __exit cmos_do_remove(struct device *dev) +static void cmos_do_remove(struct device *dev) { struct cmos_rtc *cmos = dev_get_drvdata(dev); struct resource *ports; @@ -1129,7 +1129,7 @@ static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id) pnp_irq(pnp, 0)); } -static void __exit cmos_pnp_remove(struct pnp_dev *pnp) +static void cmos_pnp_remove(struct pnp_dev *pnp) { cmos_do_remove(&pnp->dev); } @@ -1161,7 +1161,7 @@ static struct pnp_driver cmos_pnp_driver = { .name = (char *) driver_name, .id_table = rtc_ids, .probe = cmos_pnp_probe, - .remove = __exit_p(cmos_pnp_remove), + .remove = cmos_pnp_remove, .shutdown = cmos_pnp_shutdown, /* flag ensures resume() gets called, and stops syslog spam */ @@ -1238,7 +1238,7 @@ static int __init cmos_platform_probe(struct platform_device *pdev) return cmos_do_probe(&pdev->dev, resource, irq); } -static int __exit cmos_platform_remove(struct platform_device *pdev) +static int cmos_platform_remove(struct platform_device *pdev) { cmos_do_remove(&pdev->dev); return 0; @@ -1263,7 +1263,7 @@ static void cmos_platform_shutdown(struct platform_device *pdev) MODULE_ALIAS("platform:rtc_cmos"); static struct platform_driver cmos_platform_driver = { - .remove = __exit_p(cmos_platform_remove), + .remove = cmos_platform_remove, .shutdown = cmos_platform_shutdown, .driver = { .name = driver_name, @@ -1305,7 +1305,7 @@ static int __init cmos_init(void) } module_init(cmos_init); -static void __exit cmos_exit(void) +static void cmos_exit(void) { #ifdef CONFIG_PNP if (pnp_driver_registered) -- 2.7.3