[syzbot] general protection fault in __block_write_begin_int

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    764a5bc89b12 Merge tag 'drm-fixes-2021-07-30' of git://ano..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=169e4966300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=40eef000d7648480
dashboard link: https://syzkaller.appspot.com/bug?extid=dda2ebbaa98b7ee29c87
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1

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+dda2ebbaa98b7ee29c87@xxxxxxxxxxxxxxxxxxxxxxxxx

general protection fault, probably for non-canonical address 0xfbd59c0000000040: 0000 [#1] PREEMPT SMP KASAN
KASAN: maybe wild-memory-access in range [0xdead000000000200-0xdead000000000207]
CPU: 0 PID: 14330 Comm: syz-executor.0 Not tainted 5.14.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__block_write_begin_int+0xdf/0x1810 fs/buffer.c:1973
Code: c1 e8 03 42 80 3c 28 00 41 89 ec 0f 85 4e 16 00 00 48 8b 04 24 48 8b 58 18 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <80> 3c 02 00 0f 85 1e 16 00 00 48 8b 03 48 89 44 24 48 48 8b 04 24
RSP: 0018:ffffc900028df408 EFLAGS: 00010a02
RAX: dffffc0000000000 RBX: dead000000000200 RCX: ffffc9000a883000
RDX: 1bd5a00000000040 RSI: ffffffff81d82909 RDI: ffffea00020b8058
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: ffffffff819c2dde R11: 0000000000000000 R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000001000 R15: 0000000000001000
FS:  00007fdaaa33b700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055640707d930 CR3: 0000000030e6f000 CR4: 00000000001526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __block_write_begin fs/buffer.c:2056 [inline]
 block_write_begin+0x58/0x2e0 fs/buffer.c:2116
 generic_perform_write+0x202/0x500 mm/filemap.c:3656
 __generic_file_write_iter+0x24e/0x610 mm/filemap.c:3783
 blkdev_write_iter+0x298/0x550 fs/block_dev.c:1643
 call_write_iter include/linux/fs.h:2114 [inline]
 do_iter_readv_writev+0x46f/0x740 fs/read_write.c:740
 do_iter_write+0x188/0x670 fs/read_write.c:866
 vfs_iter_write+0x70/0xa0 fs/read_write.c:907
 iter_file_splice_write+0x723/0xc70 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x110/0x180 fs/splice.c:936
 splice_direct_to_actor+0x34b/0x8c0 fs/splice.c:891
 do_splice_direct+0x1b3/0x280 fs/splice.c:979
 do_sendfile+0x9f0/0x1120 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1311
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665e9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fdaaa33b188 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665e9
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000003
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000080006 R11: 0000000000000246 R12: 000000000056bf80
R13: 0000000000a9fb1f R14: 00007fdaaa33b300 R15: 0000000000022000
Modules linked in:
---[ end trace 525ffcbbca5b966c ]---
RIP: 0010:__block_write_begin_int+0xdf/0x1810 fs/buffer.c:1973
Code: c1 e8 03 42 80 3c 28 00 41 89 ec 0f 85 4e 16 00 00 48 8b 04 24 48 8b 58 18 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <80> 3c 02 00 0f 85 1e 16 00 00 48 8b 03 48 89 44 24 48 48 8b 04 24
RSP: 0018:ffffc900028df408 EFLAGS: 00010a02
RAX: dffffc0000000000 RBX: dead000000000200 RCX: ffffc9000a883000
RDX: 1bd5a00000000040 RSI: ffffffff81d82909 RDI: ffffea00020b8058
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: ffffffff819c2dde R11: 0000000000000000 R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000001000 R15: 0000000000001000
FS:  00007fdaaa33b700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000030e6f000 CR4: 00000000001526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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