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Wed, 31 Jan 2024 18:13:47 +0800 X-QQ-mid: xmsmtpt1706696027tp6rmpcp8 Message-ID: X-QQ-XMAILINFO: MB5+LsFw85NotdNI22+XGZPnNfUgGUiybdWJ8Eo2uGqD1sAOzjS+K3zrl/MabL epBHkLl59UKb809tdsgtCjG3f5+BG6MfUutWfga2YsYw+WUuhPUnZeLSXWA/JPRsWcN6ztcZQ4hY mygHz2YtFLxNzkFaooc27HJM4ZTMtXaHgxa6SUWskrpww65vWE9S7kFOLJyvJLdxMD2s3QAaDrt9 y5H79TPOKJ5nA//K5A0b2l+0wN3VeOwSUOLN6UOKnay+XMUPKhSdSR1hj2uXumc+JVnqOgI9yJKn SiKMLKhEPEGvaaWQIlk37AW7mvkY6L28yGs4TSm6sUwktXVw11UDXUrc6KTGrV0bd52x3a3OERqA xA5MvsYR44Tzzchh6l7NFryMvPJdDQ9w7NZKjMLp/IchHVT7drtipkgfW1g4J9OH0FqMpM3W/e7J AFDXrSdRXggl+z+V6dtldhsdmEujZcMMKmgeXe+T7Vz0zftdVipZlil78aPOX9KliHJezxbMZrA8 cEjWVvSLelR5zDtznR/Kn5b8aQrr8jXX8I2GJ00yRzpBceS9IcGucKGr6F8xbEudidhUCvuhXd6M NMedN4uGW2ntUTadODyTtRRq3RQXTMq6GZPqCnJ3Ra5i/h/5jxoN2IbYnggftNRGWhC9wRlVWUj+ cldxN3hS5TL9p1PERGDVqOkKdBejo0NmUiHuNEELOYFRFcr737GDlOqosuofTfFXD2FnwebQJkSv Ryx+pVJGoA0nNp+TALRO27g3OsNRFoOltdptw64OcsDZgPsWxdv8fBDQZQRZhKRB8bbSPsF7cODD SNw4XDpbeUDXazeBYzoaVcYehqU0JMT8WTXYddGS4kFsZv5CWumSkFSgzN5F+5dzIjVMM2eA2Pik KLKc+pnG6r/hfZ1h32VaA+Q6SwMIOur6XT6dl+8J1g5miwwXYPTmgNangcmKVkAo/a3ZrTShyvuh ucvKgoQ7cJ+/u1mrIVHdswBEoDGnhCIghaJfY2XNNOEBQuT+xmvRKEusdhTK6VjVyDfmZuL0ype2 jm0U0erWAiIsr7a0mOYpiBb83mhNQ= X-QQ-XMRINFO: Mp0Kj//9VHAxr69bL5MkOOs= From: Edward Adam Davis To: syzbot+2373f6be3e6de4f92562@syzkaller.appspotmail.com Cc: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [block?] [trace?] INFO: task hung in blk_trace_remove (2) Date: Wed, 31 Jan 2024 18:13:48 +0800 X-OQ-MSGID: <20240131101347.1111131-2-eadavis@qq.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <0000000000002b1fc7060fca3adf@google.com> References: <0000000000002b1fc7060fca3adf@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit please test task hung in blk_trace_remove #syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index d5d94510afd3..1af3c8aa78a3 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -311,7 +311,7 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, local_irq_restore(flags); } -static void blk_trace_free(struct request_queue *q, struct blk_trace *bt) +static void blk_trace_free_top(struct request_queue *q, struct blk_trace *bt) { relay_close(bt->rchan); @@ -325,11 +325,21 @@ static void blk_trace_free(struct request_queue *q, struct blk_trace *bt) } else { debugfs_remove(bt->dir); } +} + +static void blk_trace_free_bt(struct blk_trace *bt) +{ free_percpu(bt->sequence); free_percpu(bt->msg_data); kfree(bt); } +static void blk_trace_free(struct request_queue *q, struct blk_trace *bt) +{ + blk_trace_free_top(q, bt); + blk_trace_free_bt(bt); +} + static void get_probe_ref(void) { mutex_lock(&blk_probe_mutex); @@ -377,12 +387,23 @@ static int blk_trace_stop(struct blk_trace *bt) return 0; } +static void blk_trace_rcu_free(struct rcu_head *rcu) +{ + struct blk_trace *bt; + + bt = container_of(rcu, struct blk_trace, rcu); + if (bt) + blk_trace_free_bt(bt); +} + static void blk_trace_cleanup(struct request_queue *q, struct blk_trace *bt) { blk_trace_stop(bt); - synchronize_rcu(); - blk_trace_free(q, bt); + mutex_unlock(&q->debugfs_mutex); + blk_trace_free_top(q, bt); put_probe_ref(); + call_rcu(&bt->rcu, blk_trace_rcu_free); + mutex_lock(&q->debugfs_mutex); } static int __blk_trace_remove(struct request_queue *q) diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h index 122c62e561fc..5f927328b7e6 100644 --- a/include/linux/blktrace_api.h +++ b/include/linux/blktrace_api.h @@ -26,6 +26,7 @@ struct blk_trace { struct dentry *dir; struct list_head running_list; atomic_t dropped; + struct rcu_head rcu; }; extern int blk_trace_ioctl(struct block_device *, unsigned, char __user *);