[syzbot] [block?] BUG: unable to handle kernel NULL pointer dereference in lo_rw_aio

[syzbot] [block?] BUG: unable to handle kernel NULL pointer dereference in lo_rw_aio

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    119009db2674 Merge tag 'vfs-6.15-rc3.fixes.2' of git://git..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15c93fe4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=7a7c679f880028f0
dashboard link: https://syzkaller.appspot.com/bug?extid=6af973a3b8dfd2faefdc
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=179aeccc580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=100b5b98580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-119009db.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1cd1adb50b98/vmlinux-119009db.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d1e790c57be7/bzImage-119009db.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6af973a3b8dfd2faefdc@syzkaller.appspotmail.com

BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 0 P4D 0 
Oops: Oops: 0010 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 12 Comm: kworker/u32:0 Not tainted 6.15.0-rc2-syzkaller-00471-g119009db2674 #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: loop8 loop_rootcg_workfn
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc900000f7a38 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffffff8beceec0 RCX: ffffffff86084265
RDX: 1ffffffff17d9ddd RSI: ffffc900000f7b28 RDI: ffff8880261b3128
RBP: ffff8880261b3128 R08: 0000000000000005 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000002be0 R12: ffffc900000f7b28
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880d69b2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 000000000e180000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lo_rw_aio.isra.0+0x9c2/0xd90 drivers/block/loop.c:393
 do_req_filebacked drivers/block/loop.c:424 [inline]
 loop_handle_cmd drivers/block/loop.c:1866 [inline]
 loop_process_work+0x8a4/0x10d0 drivers/block/loop.c:1901
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
CR2: 0000000000000000
---[ end trace 0000000000000000 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc900000f7a38 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffffff8beceec0 RCX: ffffffff86084265
RDX: 1ffffffff17d9ddd RSI: ffffc900000f7b28 RDI: ffff8880261b3128
RBP: ffff8880261b3128 R08: 0000000000000005 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000002be0 R12: ffffc900000f7b28
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880d69b2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 000000000e180000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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If the report is already addressed, let syzbot know by replying with:
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#syz undup

Re: [syzbot] [block?] BUG: unable to handle kernel NULL pointer dereference in lo_rw_aio

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: unable to handle kernel NULL pointer dereference in filemap_read_folio

BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 0 P4D 0 
Oops: Oops: 0010 [#1] SMP KASAN NOPTI
CPU: 2 UID: 0 PID: 46 Comm: kworker/u32:2 Not tainted 6.15.0-rc3-syzkaller-g02ddfb981de8-dirty #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: loop8 loop_rootcg_workfn
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc90000a3f5a0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81f2b3ae
RDX: ffff88801f2bc880 RSI: ffffea0000e2d740 RDI: ffff88801fc48e00
RBP: ffffea0000e2d740 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000002be0 R12: 1ffff92000147eb5
R13: ffff88801fc48e00 R14: 0000000000000000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880d6bb2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000012f76000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 filemap_read_folio+0xc5/0x2a0 mm/filemap.c:2401
 filemap_create_folio mm/filemap.c:2536 [inline]
 filemap_get_pages+0xf39/0x1c20 mm/filemap.c:2597
 filemap_read+0x3d2/0xe90 mm/filemap.c:2702
 generic_file_read_iter+0x344/0x450 mm/filemap.c:2894
 lo_rw_aio.isra.0+0x9c2/0xd90 drivers/block/loop.c:393
 do_req_filebacked drivers/block/loop.c:424 [inline]
 loop_handle_cmd drivers/block/loop.c:1866 [inline]
 loop_process_work+0x8a4/0x10d0 drivers/block/loop.c:1901
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
CR2: 0000000000000000
---[ end trace 0000000000000000 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc90000a3f5a0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81f2b3ae
RDX: ffff88801f2bc880 RSI: ffffea0000e2d740 RDI: ffff88801fc48e00
RBP: ffffea0000e2d740 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000002be0 R12: 1ffff92000147eb5
R13: ffff88801fc48e00 R14: 0000000000000000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880d6bb2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000012f76000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


Tested on:

commit:         02ddfb98 Merge tag 'scsi-fixes' of git://git.kernel.or..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16aefd9b980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=efa83f9a6dd67d67
dashboard link: https://syzkaller.appspot.com/bug?extid=6af973a3b8dfd2faefdc
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=110efd9b980000

Re: [syzbot] [block?] BUG: unable to handle kernel NULL pointer dereference in lo_rw_aio

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+6af973a3b8dfd2faefdc@syzkaller.appspotmail.com
Tested-by: syzbot+6af973a3b8dfd2faefdc@syzkaller.appspotmail.com

Tested on:

commit:         02ddfb98 Merge tag 'scsi-fixes' of git://git.kernel.or..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14a92574580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=efa83f9a6dd67d67
dashboard link: https://syzkaller.appspot.com/bug?extid=6af973a3b8dfd2faefdc
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1411a1b3980000

Note: testing is done by a robot and is best-effort only.

Re: [syzbot] [block?] BUG: unable to handle kernel NULL pointer dereference in lo_rw_aio

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+6af973a3b8dfd2faefdc@syzkaller.appspotmail.com
Tested-by: syzbot+6af973a3b8dfd2faefdc@syzkaller.appspotmail.com

Tested on:

commit:         02ddfb98 Merge tag 'scsi-fixes' of git://git.kernel.or..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15b3fd9b980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=efa83f9a6dd67d67
dashboard link: https://syzkaller.appspot.com/bug?extid=6af973a3b8dfd2faefdc
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=13467fcf980000

Note: testing is done by a robot and is best-effort only.