From patchwork Mon Feb 24 01:31:39 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lizhi Xu X-Patchwork-Id: 13987267 Received: from mx0b-0064b401.pphosted.com (mx0b-0064b401.pphosted.com [205.220.178.238]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2165D79D0; Mon, 24 Feb 2025 01:32:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=205.220.178.238 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740360724; cv=none; b=JR9DvBMxSH3vdOUDwagQTqgZMZvXL0hZMVl1jPkG9NFuFzgJUF6dvZ4kSt7CqalnRaw+HXBUfbU8NndQ8nAB0+sqS6PmV1YEf6O/ZSrE/PHWWepzwPT8IGpTlhnCZNX9evuL0xamxc4cJRw3cEqG7opLr6rpY8GWO/zz2d4L+HY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740360724; c=relaxed/simple; bh=hU/iFiGR6L9o4jYyZ2H8U4ri1JCZwJm07ZLk81zkexQ=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=YK6vAlBqP5s97NTxRpF4gsp5Gu1RNyhsYIHoCmhiYmpkzxH/Y5EBh5ZTyRf9LVKkzUmwKg6I/8D+GxneVgPzc3NRBUz/L0YLjORo0C8xQotYA2NZZoTq1FDrDpSnANSxfJuIH8P4Gfgg/1aUbqxEuROes4eL0VC3nU0bSWuSpes= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=windriver.com; spf=pass smtp.mailfrom=windriver.com; arc=none smtp.client-ip=205.220.178.238 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=windriver.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=windriver.com Received: from pps.filterd (m0250812.ppops.net [127.0.0.1]) by mx0a-0064b401.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 51O1PiFF006096; Mon, 24 Feb 2025 01:31:44 GMT Received: from ala-exchng01.corp.ad.wrs.com (ala-exchng01.wrs.com [147.11.82.252]) by mx0a-0064b401.pphosted.com (PPS) with ESMTPS id 44y5j89n3c-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT); Mon, 24 Feb 2025 01:31:43 +0000 (GMT) Received: from ALA-EXCHNG02.corp.ad.wrs.com (147.11.82.254) by ala-exchng01.corp.ad.wrs.com (147.11.82.252) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.43; Sun, 23 Feb 2025 17:31:42 -0800 Received: from pek-lpd-ccm6.wrs.com (147.11.136.210) by ALA-EXCHNG02.corp.ad.wrs.com (147.11.82.254) with Microsoft SMTP Server id 15.1.2507.43 via Frontend Transport; Sun, 23 Feb 2025 17:31:40 -0800 From: Lizhi Xu To: CC: , , , , , Subject: [PATCH V4] module: replace the mutex lock acquisition method Date: Mon, 24 Feb 2025 09:31:39 +0800 Message-ID: <20250224013139.3994500-1-lizhi.xu@windriver.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Proofpoint-ORIG-GUID: Q3VP6zGX7_9NaR7a49ieimNowjOSrx6f X-Proofpoint-GUID: Q3VP6zGX7_9NaR7a49ieimNowjOSrx6f X-Authority-Analysis: v=2.4 cv=U+ZoDfru c=1 sm=1 tr=0 ts=67bbcbff cx=c_pps a=/ZJR302f846pc/tyiSlYyQ==:117 a=/ZJR302f846pc/tyiSlYyQ==:17 a=T2h4t0Lz3GQA:10 a=edf1wS77AAAA:8 a=hSkVLCK3AAAA:8 a=t7CeM3EgAAAA:8 a=yXnsfAS9q4kqkkg8_WUA:9 a=DcSpbTIhAlouE1Uv7lRv:22 a=cQPPKAXgyycSBL8etih5:22 a=FdTzh2GWekK77mhwV6Dw:22 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1057,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-02-23_11,2025-02-20_02,2024-11-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 phishscore=0 adultscore=0 malwarescore=0 lowpriorityscore=0 mlxscore=0 spamscore=0 impostorscore=0 mlxlogscore=999 clxscore=1015 bulkscore=0 suspectscore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.21.0-2502100000 definitions=main-2502240009 syzbot reported a deadlock in lock_system_sleep. [1] The write operation to "/sys/module/hibernate/parameters/compressor" conflicts with the registration of ieee80211 device, resulting in a deadlock in the lock param_lock. Replace the method of acquiring the lock system_transition_mutex with trylock, it is arguably better to fail a write to the module param with -EBUSY than to fail ieee80211_register_hw() IMV. Since this is not a kthread path and it doesn't call set_freezable() on itself anywhere, mutex_trylock(&system_transition_mutex) can be called from here directly. [1] syz-executor895/5833 is trying to acquire lock: ffffffff8e0828c8 (system_transition_mutex){+.+.}-{4:4}, at: lock_system_sleep+0x87/0xa0 kernel/power/main.c:56 but task is already holding lock: ffffffff8e07dc68 (param_lock){+.+.}-{4:4}, at: kernel_param_lock kernel/params.c:607 [inline] ffffffff8e07dc68 (param_lock){+.+.}-{4:4}, at: param_attr_store+0xe6/0x300 kernel/params.c:586 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (param_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730 ieee80211_rate_control_ops_get net/mac80211/rate.c:220 [inline] rate_control_alloc net/mac80211/rate.c:266 [inline] ieee80211_init_rate_ctrl_alg+0x18d/0x6b0 net/mac80211/rate.c:1015 ieee80211_register_hw+0x20cd/0x4060 net/mac80211/main.c:1531 mac80211_hwsim_new_radio+0x304e/0x54e0 drivers/net/wireless/virtual/mac80211_hwsim.c:5558 init_mac80211_hwsim+0x432/0x8c0 drivers/net/wireless/virtual/mac80211_hwsim.c:6910 do_one_initcall+0x128/0x700 init/main.c:1257 do_initcall_level init/main.c:1319 [inline] do_initcalls init/main.c:1335 [inline] do_basic_setup init/main.c:1354 [inline] kernel_init_freeable+0x5c7/0x900 init/main.c:1568 kernel_init+0x1c/0x2b0 init/main.c:1457 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #2 (rtnl_mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730 wg_pm_notification drivers/net/wireguard/device.c:80 [inline] wg_pm_notification+0x49/0x180 drivers/net/wireguard/device.c:64 notifier_call_chain+0xb7/0x410 kernel/notifier.c:85 notifier_call_chain_robust kernel/notifier.c:120 [inline] blocking_notifier_call_chain_robust kernel/notifier.c:345 [inline] blocking_notifier_call_chain_robust+0xc9/0x170 kernel/notifier.c:333 pm_notifier_call_chain_robust+0x27/0x60 kernel/power/main.c:102 snapshot_open+0x189/0x2b0 kernel/power/user.c:77 misc_open+0x35a/0x420 drivers/char/misc.c:179 chrdev_open+0x237/0x6a0 fs/char_dev.c:414 do_dentry_open+0x735/0x1c40 fs/open.c:956 vfs_open+0x82/0x3f0 fs/open.c:1086 do_open fs/namei.c:3830 [inline] path_openat+0x1e88/0x2d80 fs/namei.c:3989 do_filp_open+0x20c/0x470 fs/namei.c:4016 do_sys_openat2+0x17a/0x1e0 fs/open.c:1428 do_sys_open fs/open.c:1443 [inline] __do_sys_openat fs/open.c:1459 [inline] __se_sys_openat fs/open.c:1454 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1454 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 ((pm_chain_head).rwsem){++++}-{4:4}: down_read+0x9a/0x330 kernel/locking/rwsem.c:1524 blocking_notifier_call_chain_robust kernel/notifier.c:344 [inline] blocking_notifier_call_chain_robust+0xa9/0x170 kernel/notifier.c:333 pm_notifier_call_chain_robust+0x27/0x60 kernel/power/main.c:102 snapshot_open+0x189/0x2b0 kernel/power/user.c:77 misc_open+0x35a/0x420 drivers/char/misc.c:179 chrdev_open+0x237/0x6a0 fs/char_dev.c:414 do_dentry_open+0x735/0x1c40 fs/open.c:956 vfs_open+0x82/0x3f0 fs/open.c:1086 do_open fs/namei.c:3830 [inline] path_openat+0x1e88/0x2d80 fs/namei.c:3989 do_filp_open+0x20c/0x470 fs/namei.c:4016 do_sys_openat2+0x17a/0x1e0 fs/open.c:1428 do_sys_open fs/open.c:1443 [inline] __do_sys_openat fs/open.c:1459 [inline] __se_sys_openat fs/open.c:1454 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1454 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (system_transition_mutex){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3163 [inline] check_prevs_add kernel/locking/lockdep.c:3282 [inline] validate_chain kernel/locking/lockdep.c:3906 [inline] __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5228 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5851 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730 lock_system_sleep+0x87/0xa0 kernel/power/main.c:56 hibernate_compressor_param_set+0x1c/0x210 kernel/power/hibernate.c:1452 param_attr_store+0x18f/0x300 kernel/params.c:588 module_attr_store+0x55/0x80 kernel/params.c:924 sysfs_kf_write+0x117/0x170 fs/sysfs/file.c:139 kernfs_fop_write_iter+0x33d/0x500 fs/kernfs/file.c:334 new_sync_write fs/read_write.c:586 [inline] vfs_write+0x5ae/0x1150 fs/read_write.c:679 ksys_write+0x12b/0x250 fs/read_write.c:731 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: system_transition_mutex --> rtnl_mutex --> param_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(param_lock); lock(rtnl_mutex); lock(param_lock); lock(system_transition_mutex); *** DEADLOCK *** Reported-by: syzbot+ace60642828c074eb913@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=ace60642828c074eb913 Signed-off-by: Lizhi Xu --- V1 -> V2: use -EAGAIN to replace -EPERM. V2 -> V3: replace lock_system_sleep to trylock and update comments V3 -> V4: use system_transition_mutex directly kernel/power/hibernate.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index 10a01af63a80..b129ed1d25a8 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -1446,10 +1446,10 @@ static const char * const comp_alg_enabled[] = { static int hibernate_compressor_param_set(const char *compressor, const struct kernel_param *kp) { - unsigned int sleep_flags; int index, ret; - sleep_flags = lock_system_sleep(); + if (!mutex_trylock(&system_transition_mutex)) + return -EBUSY; index = sysfs_match_string(comp_alg_enabled, compressor); if (index >= 0) { @@ -1461,7 +1461,7 @@ static int hibernate_compressor_param_set(const char *compressor, ret = index; } - unlock_system_sleep(sleep_flags); + mutex_unlock(&system_transition_mutex); if (ret) pr_debug("Cannot set specified compressor %s\n",