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Tue, 04 Jun 2019 14:19:05 -0700 (PDT) Date: Tue, 04 Jun 2019 14:19:05 -0700 In-Reply-To: <000000000000543e45058a3cf40b@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000dac5a0058a860712@google.com> Subject: Re: possible deadlock in get_user_pages_unlocked (2) From: syzbot To: akpm@linux-foundation.org, aneesh.kumar@linux.ibm.com, dan.j.williams@intel.com, ira.weiny@intel.com, jhubbard@nvidia.com, keith.busch@intel.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, rppt@linux.ibm.com, sfr@canb.auug.org.au, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org syzbot has found a reproducer for the following crash on: HEAD commit: 56b697c6 Add linux-next specific files for 20190604 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=13241716a00000 kernel config: https://syzkaller.appspot.com/x/.config?x=4248d6bc70076f7d dashboard link: https://syzkaller.appspot.com/bug?extid=e1374b2ec8f6a25ab2e5 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=165757eea00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10dd3e86a00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+e1374b2ec8f6a25ab2e5@syzkaller.appspotmail.com IPVS: ftp: loaded support on port[0] = 21 ====================================================== WARNING: possible circular locking dependency detected 5.2.0-rc3-next-20190604 #8 Not tainted ------------------------------------------------------ syz-executor842/8767 is trying to acquire lock: 00000000badb3a6d (&mm->mmap_sem#2){++++}, at: get_user_pages_unlocked+0xfc/0x4a0 mm/gup.c:1174 but task is already holding lock: 0000000052562d44 (&sb->s_type->i_mutex_key#10){+.+.}, at: inode_trylock include/linux/fs.h:798 [inline] 0000000052562d44 (&sb->s_type->i_mutex_key#10){+.+.}, at: ext4_file_write_iter+0x246/0x1070 fs/ext4/file.c:232 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&sb->s_type->i_mutex_key#10){+.+.}: down_write+0x38/0xa0 kernel/locking/rwsem.c:66 inode_lock include/linux/fs.h:778 [inline] process_measurement+0x15ae/0x15e0 security/integrity/ima/ima_main.c:228 ima_file_mmap+0x11a/0x130 security/integrity/ima/ima_main.c:370 security_file_mprotect+0xd5/0x100 security/security.c:1426 do_mprotect_pkey+0x537/0xa30 mm/mprotect.c:550 __do_sys_mprotect mm/mprotect.c:582 [inline] __se_sys_mprotect mm/mprotect.c:579 [inline] __x64_sys_mprotect+0x78/0xb0 mm/mprotect.c:579 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&mm->mmap_sem#2){++++}: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4300 down_read+0x3f/0x1e0 kernel/locking/rwsem.c:24 get_user_pages_unlocked+0xfc/0x4a0 mm/gup.c:1174 __gup_longterm_unlocked mm/gup.c:2193 [inline] get_user_pages_fast+0x43f/0x530 mm/gup.c:2245 iov_iter_get_pages+0x2c2/0xf80 lib/iov_iter.c:1287 dio_refill_pages fs/direct-io.c:171 [inline] dio_get_page fs/direct-io.c:215 [inline] do_direct_IO fs/direct-io.c:983 [inline] do_blockdev_direct_IO+0x3f7b/0x8e00 fs/direct-io.c:1336 __blockdev_direct_IO+0xa1/0xca fs/direct-io.c:1422 ext4_direct_IO_write fs/ext4/inode.c:3782 [inline] ext4_direct_IO+0xaa7/0x1bb0 fs/ext4/inode.c:3909 generic_file_direct_write+0x20a/0x4a0 mm/filemap.c:3110 __generic_file_write_iter+0x2ee/0x630 mm/filemap.c:3293 ext4_file_write_iter+0x332/0x1070 fs/ext4/file.c:266 call_write_iter include/linux/fs.h:1870 [inline] new_sync_write+0x4d3/0x770 fs/read_write.c:483 __vfs_write+0xe1/0x110 fs/read_write.c:496 vfs_write+0x268/0x5d0 fs/read_write.c:558 ksys_write+0x14f/0x290 fs/read_write.c:611 __do_sys_write fs/read_write.c:623 [inline] __se_sys_write fs/read_write.c:620 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:620 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#10); lock(&mm->mmap_sem#2); lock(&sb->s_type->i_mutex_key#10); lock(&mm->mmap_sem#2); *** DEADLOCK *** 2 locks held by syz-executor842/8767: #0: 0000000065e8e19a (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2836 [inline] #0: 0000000065e8e19a (sb_writers#3){.+.+}, at: vfs_write+0x485/0x5d0 fs/read_write.c:557 #1: 0000000052562d44 (&sb->s_type->i_mutex_key#10){+.+.}, at: inode_trylock include/linux/fs.h:798 [inline] #1: 0000000052562d44 (&sb->s_type->i_mutex_key#10){+.+.}, at: ext4_file_write_iter+0x246/0x1070 fs/ext4/file.c:232 stack backtrace: CPU: 0 PID: 8767 Comm: syz-executor842 Not tainted 5.2.0-rc3-next-20190604 #8 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 print_circular_bug.cold+0x1cc/0x28f kernel/locking/lockdep.c:1566 check_prev_add kernel/locking/lockdep.c:2311 [inline] check_prevs_add kernel/locking/lockdep.c:2419 [inline] validate_chain kernel/locking/lockdep.c:2801 [inline] __lock_acquire+0x3755/0x5490 kernel/locking/lockdep.c:3790 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4300 down_read+0x3f/0x1e0 kernel/locking/rwsem.c:24 get_user_pages_unlocked+0xfc/0x4a0 mm/gup.c:1174 __gup_longterm_unlocked mm/gup.c:2193 [inline] get_user_pages_fast+0x43f/0x530 mm/gup.c:2245 iov_iter_get_pages+0x2c2/0xf80 lib/iov_iter.c:1287 dio_refill_pages fs/direct-io.c:171 [inline] dio_get_page fs/direct-io.c:215 [inline] do_direct_IO fs/direct-io.c:983 [inline] do_blockdev_direct_IO+0x3f7b/0x8e00 fs/direct-io.c:1336 ? 0xffffffff81000000 __blockdev_direct_IO+0xa1/0xca fs/direct-io.c:1422 ext4_direct_IO_write fs/ext4/inode.c:3782 [inline] ext4_direct_IO+0xaa7/0x1bb0 fs/ext4/inode.c:3909 generic_file_direct_write+0x20a/0x4a0 mm/filemap.c:3110 __generic_file_write_iter+0x2ee/0x630 mm/filemap.c:3293 ext4_file_write_iter+0x332/0x1070 fs/ext4/file.c:266 call_write_iter include/linux/fs.h:1870 [inline] new_sync_write+0x4d3/0x770 fs/read_write.c:483 __vfs_write+0xe1/0x110 fs/read_write.c:496 vfs_write+0x268/0x5d0 fs/read_write.c:558 ksys_write+0x14f/0x290 fs/read_write.c:611 __do_sys_write fs/read_write.c:623 [inline] __se_sys_write fs/read_write.c:620 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:620 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x440a49 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 bb 10 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffc18e28968 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00000000004a22e0 RCX: 0000000000440a49 RDX: 0000000020000012 RSI: 0000000020000000 RDI: 0000000000000005 RBP: 00000000004a2370 R08: 0000000000000012 R09: 0000000000000100 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401f90 R13: 0000000000402020 R14: 0000000000000000 R15: 0000000000000000