Hello, syzbot found the following issue on: HEAD commit: d03154e8 Add linux-next specific files for 20210128 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=16156808d00000 kernel config: https://syzkaller.appspot.com/x/.config?x=6953ffb584722a1 dashboard link: https://syzkaller.appspot.com/bug?extid=97ef6376738cb5104a71 compiler: gcc (GCC) 10.1.0-syz 20200507 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+97ef6376738cb5104a71@xxxxxxxxxxxxxxxxxxxxxxxxx BUG: Bad page state in process syz-executor.4 pfn:369c1 page:0000000025f15602 refcount:0 mapcount:0 mapping:0000000000000000 index:0x3d pfn:0x369c1 flags: 0xfff00000020005(locked|uptodate|mappedtodisk) raw: 00fff00000020005 dead000000000100 dead000000000122 0000000000000000 raw: 000000000000003d 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set Modules linked in: CPU: 1 PID: 24274 Comm: syz-executor.4 Not tainted 5.11.0-rc5-next-20210128-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 bad_page.cold+0x9c/0xbd mm/page_alloc.c:643 check_free_page_bad mm/page_alloc.c:1139 [inline] check_free_page mm/page_alloc.c:1149 [inline] free_pages_prepare mm/page_alloc.c:1265 [inline] free_pcp_prepare+0x300/0x400 mm/page_alloc.c:1306 free_unref_page_prepare mm/page_alloc.c:3201 [inline] free_unref_page+0x12/0x1b0 mm/page_alloc.c:3249 __put_single_page mm/swap.c:97 [inline] __put_page+0xe1/0x3e0 mm/swap.c:128 put_page include/linux/mm.h:1216 [inline] filemap_update_page mm/filemap.c:2326 [inline] filemap_get_pages+0x1312/0x1920 mm/filemap.c:2415 filemap_read+0x2c5/0xe40 mm/filemap.c:2475 generic_file_read_iter+0x397/0x4f0 mm/filemap.c:2626 ext4_file_read_iter+0x1d4/0x5d0 fs/ext4/file.c:130 call_read_iter include/linux/fs.h:1971 [inline] generic_file_splice_read+0x450/0x6c0 fs/splice.c:311 do_splice_to+0x1bf/0x250 fs/splice.c:796 splice_direct_to_actor+0x2c2/0x8c0 fs/splice.c:870 do_splice_direct+0x1b3/0x280 fs/splice.c:979 do_sendfile+0x9f0/0x1110 fs/read_write.c:1261 __do_sys_sendfile64 fs/read_write.c:1326 [inline] __se_sys_sendfile64 fs/read_write.c:1312 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1312 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45e219 Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fe714568c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045e219 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000003 RBP: 000000000119bfc8 R08: 0000000000000000 R09: 0000000000000000 R10: 00008400fffffff6 R11: 0000000000000246 R12: 000000000119bf8c R13: 00007ffd78dca10f R14: 00007fe7145699c0 R15: 000000000119bf8c --- 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.