Hello, syzbot found the following issue on: HEAD commit: cf7cd542 Add linux-next specific files for 20201104 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=14649314500000 kernel config: https://syzkaller.appspot.com/x/.config?x=e8dc0c5ac73afb92 dashboard link: https://syzkaller.appspot.com/bug?extid=46061b9b42fecc6e7d6d 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+46061b9b42fecc6e7d6d@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: slab-out-of-bounds in io_uring_show_cred+0x598/0x5f0 fs/io_uring.c:9225 Read of size 4 at addr ffff8880253d13c8 by task syz-executor.3/10456 CPU: 1 PID: 10456 Comm: syz-executor.3 Not tainted 5.10.0-rc2-next-20201104-syzkaller #0 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+0x107/0x163 lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x4c8 mm/kasan/report.c:385 __kasan_report mm/kasan/report.c:545 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562 io_uring_show_cred+0x598/0x5f0 fs/io_uring.c:9225 idr_for_each+0x113/0x220 lib/idr.c:208 __io_uring_show_fdinfo fs/io_uring.c:9272 [inline] io_uring_show_fdinfo+0x923/0xda0 fs/io_uring.c:9294 seq_show+0x4a8/0x700 fs/proc/fd.c:65 seq_read+0x432/0x1070 fs/seq_file.c:208 do_loop_readv_writev fs/read_write.c:761 [inline] do_loop_readv_writev fs/read_write.c:748 [inline] do_iter_read+0x48e/0x6e0 fs/read_write.c:803 vfs_readv+0xe5/0x150 fs/read_write.c:921 do_preadv fs/read_write.c:1013 [inline] __do_sys_preadv fs/read_write.c:1063 [inline] __se_sys_preadv fs/read_write.c:1058 [inline] __x64_sys_preadv+0x231/0x310 fs/read_write.c:1058 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45deb9 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:00007f691c7eac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 0000000000025e40 RCX: 000000000045deb9 RDX: 0000000000000333 RSI: 00000000200017c0 RDI: 0000000000000005 RBP: 000000000118c018 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bfd4 R13: 00007ffef15d676f R14: 00007f691c7eb9c0 R15: 000000000118bfd4 Allocated by task 10448: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:461 kmalloc include/linux/slab.h:552 [inline] io_register_personality fs/io_uring.c:9647 [inline] __io_uring_register fs/io_uring.c:9883 [inline] __do_sys_io_uring_register+0x10f0/0x40a0 fs/io_uring.c:9933 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff8880253d1380 which belongs to the cache kmalloc-96 of size 96 The buggy address is located 72 bytes inside of 96-byte region [ffff8880253d1380, ffff8880253d13e0) The buggy address belongs to the page: page:000000003c207268 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x253d1 flags: 0xfff00000000200(slab) raw: 00fff00000000200 ffffea0000a900c0 0000000500000005 ffff888010041780 raw: 0000000000000000 0000000080200020 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880253d1280: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc ffff8880253d1300: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc >ffff8880253d1380: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc ^ ffff8880253d1400: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc ffff8880253d1480: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc ================================================================== --- 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.
