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Sun, 11 Apr 2021 01:14:44 -0700 (PDT) To: Hao Sun , axboe@kernel.dk, io-uring@vger.kernel.org Cc: linux-kernel@vger.kernel.org References: From: Pavel Begunkov Autocrypt: addr=asml.silence@gmail.com; prefer-encrypt=mutual; keydata= mQINBFmKBOQBEAC76ZFxLAKpDw0bKQ8CEiYJRGn8MHTUhURL02/7n1t0HkKQx2K1fCXClbps bdwSHrhOWdW61pmfMbDYbTj6ZvGRvhoLWfGkzujB2wjNcbNTXIoOzJEGISHaPf6E2IQx1ik9 6uqVkK1OMb7qRvKH0i7HYP4WJzYbEWVyLiAxUj611mC9tgd73oqZ2pLYzGTqF2j6a/obaqha +hXuWTvpDQXqcOZJXIW43atprH03G1tQs7VwR21Q1eq6Yvy2ESLdc38EqCszBfQRMmKy+cfp W3U9Mb1w0L680pXrONcnlDBCN7/sghGeMHjGKfNANjPc+0hzz3rApPxpoE7HC1uRiwC4et83 CKnncH1l7zgeBT9Oa3qEiBlaa1ZCBqrA4dY+z5fWJYjMpwI1SNp37RtF8fKXbKQg+JuUjAa9 Y6oXeyEvDHMyJYMcinl6xCqCBAXPHnHmawkMMgjr3BBRzODmMr+CPVvnYe7BFYfoajzqzq+h EyXSl3aBf0IDPTqSUrhbmjj5OEOYgRW5p+mdYtY1cXeK8copmd+fd/eTkghok5li58AojCba jRjp7zVOLOjDlpxxiKhuFmpV4yWNh5JJaTbwCRSd04sCcDNlJj+TehTr+o1QiORzc2t+N5iJ NbILft19Izdn8U39T5oWiynqa1qCLgbuFtnYx1HlUq/HvAm+kwARAQABtDFQYXZlbCBCZWd1 bmtvdiAoc2lsZW5jZSkgPGFzbWwuc2lsZW5jZUBnbWFpbC5jb20+iQJOBBMBCAA4FiEE+6Ju PTjTbx479o3OWt5b1Glr+6UFAlmKBOQCGwMFCwkIBwIGFQgJCgsCBBYCAwECHgECF4AACgkQ Wt5b1Glr+6WxZA//QueaKHzgdnOikJ7NA/Vq8FmhRlwgtP0+E+w93kL+ZGLzS/cUCIjn2f4Q Mcutj2Neg0CcYPX3b2nJiKr5Vn0rjJ/suiaOa1h1KzyNTOmxnsqE5fmxOf6C6x+NKE18I5Jy xzLQoktbdDVA7JfB1itt6iWSNoOTVcvFyvfe5ggy6FSCcP+m1RlR58XxVLH+qlAvxxOeEr/e aQfUzrs7gqdSd9zQGEZo0jtuBiB7k98t9y0oC9Jz0PJdvaj1NZUgtXG9pEtww3LdeXP/TkFl HBSxVflzeoFaj4UAuy8+uve7ya/ECNCc8kk0VYaEjoVrzJcYdKP583iRhOLlZA6HEmn/+Gh9 4orG67HNiJlbFiW3whxGizWsrtFNLsSP1YrEReYk9j1SoUHHzsu+ZtNfKuHIhK0sU07G1OPN 2rDLlzUWR9Jc22INAkhVHOogOcc5ajMGhgWcBJMLCoi219HlX69LIDu3Y34uIg9QPZIC2jwr 24W0kxmK6avJr7+n4o8m6sOJvhlumSp5TSNhRiKvAHB1I2JB8Q1yZCIPzx+w1ALxuoWiCdwV M/azguU42R17IuBzK0S3hPjXpEi2sK/k4pEPnHVUv9Cu09HCNnd6BRfFGjo8M9kZvw360gC1 reeMdqGjwQ68o9x0R7NBRrtUOh48TDLXCANAg97wjPoy37dQE7e5Ag0EWYoE5AEQAMWS+aBV IJtCjwtfCOV98NamFpDEjBMrCAfLm7wZlmXy5I6o7nzzCxEw06P2rhzp1hIqkaab1kHySU7g dkpjmQ7Jjlrf6KdMP87mC/Hx4+zgVCkTQCKkIxNE76Ff3O9uTvkWCspSh9J0qPYyCaVta2D1 Sq5HZ8WFcap71iVO1f2/FEHKJNz/YTSOS/W7dxJdXl2eoj3gYX2UZNfoaVv8OXKaWslZlgqN jSg9wsTv1K73AnQKt4fFhscN9YFxhtgD/SQuOldE5Ws4UlJoaFX/yCoJL3ky2kC0WFngzwRF Yo6u/KON/o28yyP+alYRMBrN0Dm60FuVSIFafSqXoJTIjSZ6olbEoT0u17Rag8BxnxryMrgR dkccq272MaSS0eOC9K2rtvxzddohRFPcy/8bkX+t2iukTDz75KSTKO+chce62Xxdg62dpkZX xK+HeDCZ7gRNZvAbDETr6XI63hPKi891GeZqvqQVYR8e+V2725w+H1iv3THiB1tx4L2bXZDI DtMKQ5D2RvCHNdPNcZeldEoJwKoA60yg6tuUquvsLvfCwtrmVI2rL2djYxRfGNmFMrUDN1Xq F3xozA91q3iZd9OYi9G+M/OA01husBdcIzj1hu0aL+MGg4Gqk6XwjoSxVd4YT41kTU7Kk+/I 5/Nf+i88ULt6HanBYcY/+Daeo/XFABEBAAGJAjYEGAEIACAWIQT7om49ONNvHjv2jc5a3lvU aWv7pQUCWYoE5AIbDAAKCRBa3lvUaWv7pfmcEACKTRQ28b1y5ztKuLdLr79+T+LwZKHjX++P 4wKjEOECCcB6KCv3hP+J2GCXDOPZvdg/ZYZafqP68Yy8AZqkfa4qPYHmIdpODtRzZSL48kM8 LRzV8Rl7J3ItvzdBRxf4T/Zseu5U6ELiQdCUkPGsJcPIJkgPjO2ROG/ZtYa9DvnShNWPlp+R uPwPccEQPWO/NP4fJl2zwC6byjljZhW5kxYswGMLBwb5cDUZAisIukyAa8Xshdan6C2RZcNs rB3L7vsg/R8UCehxOH0C+NypG2GqjVejNZsc7bgV49EOVltS+GmGyY+moIzxsuLmT93rqyII 5rSbbcTLe6KBYcs24XEoo49Zm9oDA3jYvNpeYD8rDcnNbuZh9kTgBwFN41JHOPv0W2FEEWqe JsCwQdcOQ56rtezdCJUYmRAt3BsfjN3Jn3N6rpodi4Dkdli8HylM5iq4ooeb5VkQ7UZxbCWt UVMKkOCdFhutRmYp0mbv2e87IK4erwNHQRkHUkzbsuym8RVpAZbLzLPIYK/J3RTErL6Z99N2 m3J6pjwSJY/zNwuFPs9zGEnRO4g0BUbwGdbuvDzaq6/3OJLKohr5eLXNU3JkT+3HezydWm3W OPhauth7W0db74Qd49HXK0xe/aPrK+Cp+kU1HRactyNtF8jZQbhMCC8vMGukZtWaAwpjWiiH bA== Subject: Re: BUG: unable to handle kernel NULL pointer dereference in io_uring_cancel_task_requests Message-ID: <461a8447-bc48-145f-c3dc-4b049621afcc@gmail.com> Date: Sun, 11 Apr 2021 09:10:37 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 11/04/2021 04:08, Hao Sun wrote: > Hi > > When using Healer(https://github.com/SunHao-0/healer/tree/dev) to fuzz > the Linux kernel, I found a null-ptr-deref bug in > io_uring_cancel_task_requests under fault injection condition, but I'm > not sure about this. > Sorry, I do not have a reproducing program for this bug. > I hope that the stack trace information in the crash log can help you > locate the problem. Thanks Hao. io_cqring_wait() fails should not anyhow affect cancellation, so the log doesn't make sense from first sight, something strange is going on. > > Here is the details: > commit: 3b9cdafb5358eb9f3790de2f728f765fef100731 > version: linux 5.11 > git tree: upstream > Full log can be found in the attachment. > cqwait() > Fault injection log: > FAULT_INJECTION: forcing a failure. > name fail_usercopy, interval 1, probability 0, space 0, times 0 > CPU: 1 PID: 9161 Comm: executor Not tainted 5.11.0+ #5 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 > Call Trace: > __dump_stack lib/dump_stack.c:79 [inline] > dump_stack+0x137/0x194 lib/dump_stack.c:120 > fail_dump lib/fault-inject.c:52 [inline] > should_fail+0x23e/0x250 lib/fault-inject.c:146 > should_fail_usercopy+0x16/0x20 lib/fault-inject-usercopy.c:37 > _copy_from_user+0x1c/0xd0 lib/usercopy.c:14 > copy_from_user include/linux/uaccess.h:192 [inline] > set_user_sigmask+0x4b/0x110 kernel/signal.c:3015 > io_cqring_wait+0x2e3/0x8b0 fs/io_uring.c:7250 > __do_sys_io_uring_enter fs/io_uring.c:9480 [inline] > __se_sys_io_uring_enter+0x8fc/0xb70 fs/io_uring.c:9397 > __x64_sys_io_uring_enter+0x74/0x80 fs/io_uring.c:9397 > do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xae > RIP: 0033:0x46a379 > Code: f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 48 89 f8 48 > 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d > 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007f046fa19c58 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa > RAX: ffffffffffffffda RBX: 000000000078c080 RCX: 000000000046a379 > RDX: 00000000000066ab RSI: 0000000000000001 RDI: 0000000000000003 > RBP: 00007f046fa19c90 R08: 0000000020000040 R09: 0000000000000008 > R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000 > R13: 0000000000000000 R14: 000000000078c080 R15: 00007fff769deef0 > > Crash log: > BUG: kernel NULL pointer dereference, address: 0000000000000040 > #PF: supervisor read access in kernel mode > #PF: error_code(0x0000) - not-present page > PGD 49954067 P4D 49954067 PUD 45f92067 PMD 0 > Oops: 0000 [#1] PREEMPT SMP > CPU: 1 PID: 9161 Comm: executor Not tainted 5.11.0+ #5 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 > RIP: 0010:io_uring_cancel_task_requests+0x3f/0x990 fs/io_uring.c:9045 > Code: 48 8b 04 25 28 00 00 00 48 89 44 24 68 e8 89 e6 c5 ff 65 4c 8b > 34 25 00 6d 01 00 49 8d 7c 24 40 48 89 7c 24 30 e8 81 97 d6 ff <41> 8b > 5c 24 40 89 de 83 e6 02 31 ff e8 70 ea c5 ff 83 e3 02 48 89 > RSP: 0018:ffffc90002a97b48 EFLAGS: 00010246 > RAX: ffff88804b8e0d38 RBX: ffff88804b8ad700 RCX: 0000000000000764 > RDX: 0000000000000040 RSI: ffff8880409d5140 RDI: 0000000000000040 > RBP: ffff8880409d5140 R08: 0000000000000000 R09: 0000000000000043 > R10: 0001ffffffffffff R11: ffff88804b8e0280 R12: 0000000000000000 > R13: ffff8880409d5140 R14: ffff88804b8e0280 R15: ffff8880481c1800 > FS: 00007f046fa1a700(0000) GS:ffff88807ec00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000000040 CR3: 00000000479a5000 CR4: 0000000000750ee0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > PKRU: 55555554 > Call Trace: > __io_uring_files_cancel+0x9b/0x200 fs/io_uring.c:9140 > io_uring_files_cancel include/linux/io_uring.h:65 [inline] > do_exit+0x1a8/0x16d0 kernel/exit.c:780 > do_group_exit+0xc5/0x180 kernel/exit.c:922 > get_signal+0xd90/0x1470 kernel/signal.c:2773 > arch_do_signal_or_restart+0x2a/0x260 arch/x86/kernel/signal.c:811 > handle_signal_work kernel/entry/common.c:147 [inline] > exit_to_user_mode_loop kernel/entry/common.c:171 [inline] > exit_to_user_mode_prepare+0x109/0x1a0 kernel/entry/common.c:208 > __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline] > syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:301 > do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56 > entry_SYSCALL_64_after_hwframe+0x44/0xae > RIP: 0033:0x46a379 > Code: f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 48 89 f8 48 > 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d > 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007f046fa19cd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca > RAX: fffffffffffffe00 RBX: 000000000078c080 RCX: 000000000046a379 > RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000078c088 > RBP: 000000000078c088 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078c08c > R13: 0000000000000000 R14: 000000000078c080 R15: 00007fff769deef0 > Modules linked in: > Dumping ftrace buffer: > (ftrace buffer empty) > CR2: 0000000000000040 > ---[ end trace 613db1a25ecf6443 ]--- > RIP: 0010:io_uring_cancel_task_requests+0x3f/0x990 fs/io_uring.c:9045 > Code: 48 8b 04 25 28 00 00 00 48 89 44 24 68 e8 89 e6 c5 ff 65 4c 8b > 34 25 00 6d 01 00 49 8d 7c 24 40 48 89 7c 24 30 e8 81 97 d6 ff <41> 8b > 5c 24 40 89 de 83 e6 02 31 ff e8 70 ea c5 ff 83 e3 02 48 89 > RSP: 0018:ffffc90002a97b48 EFLAGS: 00010246 > RAX: ffff88804b8e0d38 RBX: ffff88804b8ad700 RCX: 0000000000000764 > RDX: 0000000000000040 RSI: ffff8880409d5140 RDI: 0000000000000040 > RBP: ffff8880409d5140 R08: 0000000000000000 R09: 0000000000000043 > R10: 0001ffffffffffff R11: ffff88804b8e0280 R12: 0000000000000000 > R13: ffff8880409d5140 R14: ffff88804b8e0280 R15: ffff8880481c1800 > FS: 00007f046fa1a700(0000) GS:ffff88807ec00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000000040 CR3: 00000000479a5000 CR4: 0000000000750ee0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > PKRU: 55555554 > -- Pavel Begunkov