Hello, syzbot found the following issue on: HEAD commit: e28f0104 Merge tag 'fixes-2020-09-03' of git://git.kernel... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=11a6b859900000 kernel config: https://syzkaller.appspot.com/x/.config?x=3c5f6ce8d5b68299 dashboard link: https://syzkaller.appspot.com/bug?extid=4d428ef55ad3356698bf compiler: gcc (GCC) 10.1.0-syz 20200507 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13949019900000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14fe9e3e900000 Bisection is inconclusive: the issue happens on the oldest tested release. bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=12b6a5ae900000 final oops: https://syzkaller.appspot.com/x/report.txt?x=11b6a5ae900000 console output: https://syzkaller.appspot.com/x/log.txt?x=16b6a5ae900000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+4d428ef55ad3356698bf@xxxxxxxxxxxxxxxxxxxxxxxxx BUG: unable to handle page fault for address: ffffe8ffffc33c70 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 77000000000000 P4D 77000000000000 Oops: 0002 [#1] PREEMPT SMP KASAN CPU: 0 PID: 10445 Comm: syz-executor899 Not tainted 5.9.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:percpu_down_read_trylock include/linux/percpu-rwsem.h:82 [inline] RIP: 0010:__sb_start_write+0x16e/0x470 fs/super.c:1674 Code: 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 e3 02 00 00 41 bd 01 00 00 00 bd 01 00 00 00 48 8b 43 68 <65> ff 00 e8 aa 6b b4 ff bf 01 00 00 00 e8 e0 d5 8f ff 31 ff 65 44 RSP: 0018:ffffc9000a0bfab8 EFLAGS: 00010246 RAX: 0000607f51633c70 RBX: ffff888098be2380 RCX: ffffffff81bfdf07 RDX: 1ffff1101317c47d RSI: 0000000000000001 RDI: ffff888098be23e8 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000001 R14: 0000000000000000 R15: ffff8880854bc0b0 FS: 00007fa632ef6700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffe8ffffc33c70 CR3: 000000000011b000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: sb_start_write_trylock include/linux/fs.h:1648 [inline] touch_atime+0x152/0x370 fs/inode.c:1831 file_accessed include/linux/fs.h:2206 [inline] splice_direct_to_actor+0x762/0x980 fs/splice.c:989 do_splice_direct+0x1b3/0x280 fs/splice.c:1059 do_sendfile+0x55f/0xd40 fs/read_write.c:1540 __do_sys_sendfile64 fs/read_write.c:1601 [inline] __se_sys_sendfile64 fs/read_write.c:1587 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1587 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x446ac9 Code: Bad RIP value. RSP: 002b:00007fa632ef5d18 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00000000006dbc58 RCX: 0000000000446ac9 RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000004 RBP: 00000000006dbc50 R08: 65732f636f72702f R09: 65732f636f72702f R10: 0800000080004101 R11: 0000000000000246 R12: 00000000006dbc5c R13: 00007fa632ef5d20 R14: 00007fa632ef5d20 R15: 20c49ba5e353f7cf Modules linked in: CR2: ffffe8ffffc33c70 ---[ end trace 641e2e487fb96738 ]--- RIP: 0010:percpu_down_read_trylock include/linux/percpu-rwsem.h:82 [inline] RIP: 0010:__sb_start_write+0x16e/0x470 fs/super.c:1674 Code: 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 e3 02 00 00 41 bd 01 00 00 00 bd 01 00 00 00 48 8b 43 68 <65> ff 00 e8 aa 6b b4 ff bf 01 00 00 00 e8 e0 d5 8f ff 31 ff 65 44 RSP: 0018:ffffc9000a0bfab8 EFLAGS: 00010246 RAX: 0000607f51633c70 RBX: ffff888098be2380 RCX: ffffffff81bfdf07 RDX: 1ffff1101317c47d RSI: 0000000000000001 RDI: ffff888098be23e8 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000001 R14: 0000000000000000 R15: ffff8880854bc0b0 FS: 00007fa632ef6700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000446a9f CR3: 000000000011b000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches
