Hello, syzbot found the following issue on: HEAD commit: fcadab74 Merge tag 'drm-fixes-2020-10-01-1' of git://anong.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=15d14513900000 kernel config: https://syzkaller.appspot.com/x/.config?x=89ab6a0c48f30b49 dashboard link: https://syzkaller.appspot.com/bug?extid=9cee17fa4a973a9e60f2 compiler: gcc (GCC) 10.1.0-syz 20200507 userspace arch: i386 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+9cee17fa4a973a9e60f2@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: double-free or invalid-free in put_files_struct fs/file.c:434 [inline] BUG: KASAN: double-free or invalid-free in put_files_struct+0x2c8/0x350 fs/file.c:426 CPU: 0 PID: 27522 Comm: syz-executor.0 Not tainted 5.9.0-rc7-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+0x198/0x1fd lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383 kasan_report_invalid_free+0x51/0x80 mm/kasan/report.c:477 __kasan_slab_free+0x107/0x120 mm/kasan/common.c:401 __cache_free mm/slab.c:3422 [inline] kmem_cache_free.part.0+0x74/0x1e0 mm/slab.c:3697 put_files_struct fs/file.c:434 [inline] put_files_struct+0x2c8/0x350 fs/file.c:426 exit_files+0x7e/0xa0 fs/file.c:458 do_exit+0xb43/0x29f0 kernel/exit.c:801 do_group_exit+0x125/0x310 kernel/exit.c:903 get_signal+0x428/0x1f00 kernel/signal.c:2757 arch_do_signal+0x82/0x2520 arch/x86/kernel/signal.c:811 exit_to_user_mode_loop kernel/entry/common.c:161 [inline] exit_to_user_mode_prepare+0x1ae/0x200 kernel/entry/common.c:192 syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:267 __do_fast_syscall_32+0x6c/0x90 arch/x86/entry/common.c:138 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:160 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf7f41549 Code: Bad RIP value. RSP: 002b:00000000f553b0cc EFLAGS: 00000296 ORIG_RAX: 0000000000000171 RAX: 0000000000090fc0 RBX: 0000000000000004 RCX: 0000000020f6f000 RDX: 00000000fffffea7 RSI: 0000000020000004 RDI: 0000000020b63fe4 RBP: 000000000000001c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 30131: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 slab_post_alloc_hook mm/slab.h:518 [inline] slab_alloc mm/slab.c:3316 [inline] kmem_cache_alloc+0x13a/0x3f0 mm/slab.c:3486 dup_fd+0x89/0xc90 fs/file.c:293 copy_files kernel/fork.c:1461 [inline] copy_process+0x1d99/0x6940 kernel/fork.c:2058 _do_fork+0xe8/0xb10 kernel/fork.c:2429 __do_sys_clone3+0x1dd/0x320 kernel/fork.c:2704 do_syscall_32_irqs_on arch/x86/entry/common.c:78 [inline] __do_fast_syscall_32+0x60/0x90 arch/x86/entry/common.c:137 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:160 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c The buggy address belongs to the object at ffff88805c9a00c0 which belongs to the cache files_cache of size 832 The buggy address is located 192 bytes to the left of 832-byte region [ffff88805c9a00c0, ffff88805c9a0400) The buggy address belongs to the page: page:00000000953999c6 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88805c9a0840 pfn:0x5c9a0 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea0002669748 ffffea0002a460c8 ffff88821bc47500 raw: ffff88805c9a0840 ffff88805c9a00c0 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88805c99ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88805c99ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88805c9a0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ^ ffff88805c9a0080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88805c9a0100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ================================================================== --- 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.
