Re: A null-ptr-deref bug in f2fs_write_end_io

[Chao Yu]

On 2023/5/22 11:58, butt3rflyh4ck wrote:
> OK, the attachment is a reproducer.

Thank you!

I've figured out a patch, could you please have a try w/ this patch?

https://lore.kernel.org/linux-f2fs-devel/20230522124203.3838360-1-chao@xxxxxxxxxx/

Thanks,

> Regards.
>   butt3rflyh4ck.
>
> On Fri, May 19, 2023 at 11:24 PM Chao Yu <chao@xxxxxxxxxx> wrote:
> > Hi,
> >
> > Thanks for the report, it will be helpful if you can provide a
> > reproducer.
> >
> > On 2023/5/19 15:13, butt3rflyh4ck wrote:
> > > Hi, there is a null-ptr-deref  bug in f2fs_write_end_io in
> > > fs/f2fs/data.c, I reproduce it in the latest kernel too.
> > >
> > > #Quick description
> > > When a thread always calls F2FS_IOC_RESIZE_FS to  resize fs, if resize
> > > fs is failed, f2fs kernel thread would  invoke callback function to
> > > update
> > > f2fs io info, it would call  f2fs_write_end_io and may trigger
> > > null-ptr-deref in NODE_MAPPING.
> > > ```
> > > static inline struct address_space *NODE_MAPPING(struct f2fs_sb_info *sbi)
> > > {
> > > return sbi->node_inode->i_mapping;
> > > }
> > > ```
> > > there is deref in sbi.
> > >
> > > #crash log
> > > ----------------------------------------
> > > general protection fault, probably for non-canonical address
> > > 0xdffffc0000000006: 0000 [#1] PREEMPT SMP KASAN
> > > KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
> > > CPU: 0 PID: 17 Comm: ksoftirqd/0 Not tainted 6.4.0-rc1 #18
> > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
> > > RIP: 0010:NODE_MAPPING fs/f2fs/f2fs.h:1972 [inline]
> > > RIP: 0010:f2fs_write_end_io+0x727/0x1050 fs/f2fs/data.c:370
> > > Code: 00 00 48 89 f8 48 c1 e8 03 80 3c 18 00 0f 85 b3 07 00 00 48 8b
> > > 44 24 08 4c 8b a8 60 01 00 00 49 8d 7d 30 48 89 f8 48 c1 e8 03 <80> 3c
> > > 18 00 0f 85 9c 07 00 00 4d 3b 75 30 0f 84 10 04 00 00 e8 10
> > > RSP: 0018:ffffc9000042fc78 EFLAGS: 00010216
> > > RAX: 0000000000000006 RBX: dffffc0000000000 RCX: 0000000000000100
> > > RDX: ffff888013d18000 RSI: ffffffff83a93a4d RDI: 0000000000000030
> > > RBP: ffffea00009e6900 R08: 0000000000000001 R09: 0000000000000000
> > > R10: 0000000000000000 R11: 0000000000000000 R12: ffffea00009e6900
> > > R13: 0000000000000000 R14: ffff88802a3cec48 R15: 0000000000000000
> > > FS:  0000000000000000(0000) GS:ffff88802ca00000(0000) knlGS:0000000000000000
> > > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > CR2: 0000555faf194000 CR3: 00000000251bd000 CR4: 0000000000750ef0
> > > PKRU: 55555554
> > > Call Trace:
> > >    <TASK>
> > >    bio_endio+0x5af/0x6c0 block/bio.c:1608
> > >    req_bio_endio block/blk-mq.c:761 [inline]
> > >    blk_update_request+0x5cc/0x1690 block/blk-mq.c:906
> > >    blk_mq_end_request+0x59/0x4c0 block/blk-mq.c:1023
> > >    lo_complete_rq+0x1c6/0x280 drivers/block/loop.c:370
> > >    blk_complete_reqs+0xad/0xe0 block/blk-mq.c:1101
> > >    __do_softirq+0x1d4/0x8ef kernel/softirq.c:571
> > >    run_ksoftirqd kernel/softirq.c:939 [inline]
> > >    run_ksoftirqd+0x31/0x60 kernel/softirq.c:931
> > >    smpboot_thread_fn+0x659/0x9e0 kernel/smpboot.c:164
> > >    kthread+0x33e/0x440 kernel/kthread.c:379
> > >    ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
> > >    </TASK>
> > > Modules linked in:
> > > ---[ end trace 0000000000000000 ]---
> > > RIP: 0010:NODE_MAPPING fs/f2fs/f2fs.h:1972 [inline]
> > > RIP: 0010:f2fs_write_end_io+0x727/0x1050 fs/f2fs/data.c:370
> > > Code: 00 00 48 89 f8 48 c1 e8 03 80 3c 18 00 0f 85 b3 07 00 00 48 8b
> > > 44 24 08 4c 8b a8 60 01 00 00 49 8d 7d 30 48 89 f8 48 c1 e8 03 <80> 3c
> > > 18 00 0f 85 9c 07 00 00 4d 3b 75 30 0f 84 10 04 00 00 e8 10
> > > RSP: 0018:ffffc9000042fc78 EFLAGS: 00010216
> > > RAX: 0000000000000006 RBX: dffffc0000000000 RCX: 0000000000000100
> > > RDX: ffff888013d18000 RSI: ffffffff83a93a4d RDI: 0000000000000030
> > > RBP: ffffea00009e6900 R08: 0000000000000001 R09: 0000000000000000
> > > R10: 0000000000000000 R11: 0000000000000000 R12: ffffea00009e6900
> > > R13: 0000000000000000 R14: ffff88802a3cec48 R15: 0000000000000000
> > > FS:  0000000000000000(0000) GS:ffff88802ca00000(0000) knlGS:0000000000000000
> > > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > CR2: 0000555faf194000 CR3: 00000000251bd000 CR4: 0000000000750ef0
> > > PKRU: 55555554
> > > -----------------------
> > >
> > > # new crash log in latest kernel
> > > ---------------------
> > > [  193.695164][ T8174] loop0: detected capacity change from 0 to 264192
> > > [  193.696467][ T8174] F2FS-fs (loop0): Magic Mismatch,
> > > valid(0xf2f52010) - read(0x0)
> > > [  193.696875][ T8174] F2FS-fs (loop0): Can't find valid F2FS
> > > filesystem in 2th superblock
> > > [  193.698363][ T8174] F2FS-fs (loop0): invalid crc_offset: 0
> > > [  193.700454][ T8174] F2FS-fs (loop0): Disable nat_bits due to
> > > incorrect cp_ver (4542359912962316977, 0)
> > > [  193.716594][ T8174] F2FS-fs (loop0): Try to recover 2th superblock, ret: 0
> > > [  193.717102][ T8174] F2FS-fs (loop0): Mounted with checkpoint
> > > version = 3e17dab1
> > > [  193.743330][ T8174] F2FS-fs (loop0): For resize: curseg of type 0: 46 ==> 4
> > > [  193.743904][ T8174] F2FS-fs (loop0): For resize: curseg of type 3: 52 ==> 6
> > > [  193.745690][ T8174] F2FS-fs (loop0): For resize: curseg of type 4: 50 ==> 8
> > > [  193.746108][ T8174] F2FS-fs (loop0): For resize: curseg of type 5: 48 ==> 10
> > > [  193.751857][ T8174] F2FS-fs (loop0): resize_fs failed, should run
> > > fsck to repair!
> > > [  193.780283][    C0] general protection fault, probably for
> > > non-canonical address 0xdffffc0000000006: 0000 [#1] PREEMPT SMP KASAN
> > > [  193.781027][    C0] KASAN: null-ptr-deref in range
> > > [0x0000000000000030-0x0000000000000037]
> > > [  193.781572][    C0] CPU: 0 PID: 17 Comm: ksoftirqd/0 Not tainted
> > > 6.4.0-rc2-00163-g2d1bcbc6cd70-dirty #17
> > > [  193.782201][    C0] Hardware name: QEMU Standard PC (i440FX + PIIX,
> > > 1996), BIOS 1.15.0-1 04/01/2014
> > > [  193.782727][    C0] RIP: 0010:f2fs_write_end_io+0x727/0x1050
> > > [  193.783083][    C0] Code: 00 00 48 89 f8 48 c1 e8 03 80 3c 18 00 0f
> > > 85 b3 07 00 00 48 8b 44 24 08 4c 8b a8 60 01 00 00 49 8d 7d 30 48 89
> > > f8 48 c1 e8 03 <80> 3c 18 00 0f 85 9c 07 00 00 4d 3b 75 30 0f 0
> > > [  193.784268][    C0] RSP: 0018:ffffc9000042fc78 EFLAGS: 00010216
> > > [  193.784629][    C0] RAX: 0000000000000006 RBX: dffffc0000000000
> > > RCX: 0000000000000100
> > > [  193.785109][    C0] RDX: ffff888013d18000 RSI: ffffffff83a9588d
> > > RDI: 0000000000000030
> > > [  193.785576][    C0] RBP: ffffea000143e740 R08: 0000000000000001
> > > R09: 0000000000000000
> > > [  193.786051][    C0] R10: 0000000000000000 R11: 0000000000000000
> > > R12: ffffea000143e740
> > > [  193.786571][    C0] R13: 0000000000000000 R14: ffff888041423738
> > > R15: 0000000000000000
> > > [  193.787055][    C0] FS:  0000000000000000(0000)
> > > GS:ffff88802ca00000(0000) knlGS:0000000000000000
> > > [  193.787620][    C0] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > [  193.787997][    C0] CR2: 000056056fd87000 CR3: 000000001b546000
> > > CR4: 00000000000006f0
> > > [  193.788585][    C0] Call Trace:
> > > [  193.788863][    C0]  <TASK>
> > > [  193.789115][    C0]  ? bio_uninit+0x1b7/0x410
> > > [  193.789509][    C0]  ? f2fs_write_end+0xa80/0xa80
> > > [  193.790053][    C0]  bio_endio+0x5af/0x6c0
> > > [  193.790522][    C0]  blk_update_request+0x5cc/0x1690
> > > [  193.791171][    C0]  blk_mq_end_request+0x59/0x4c0
> > > [  193.791695][    C0]  lo_complete_rq+0x1c6/0x280
> > > [  193.792247][    C0]  blk_complete_reqs+0xad/0xe0
> > > [  193.792759][    C0]  __do_softirq+0x1d4/0x8ef
> > > [  193.793312][    C0]  ? __irq_exit_rcu+0x190/0x190
> > > [  193.793805][    C0]  run_ksoftirqd+0x31/0x60
> > > [  193.794183][    C0]  smpboot_thread_fn+0x659/0x9e0
> > > [  193.794576][    C0]  ? sort_range+0x30/0x30
> > > [  193.794900][    C0]  kthread+0x33e/0x440
> > > [  193.795263][    C0]  ? kthread_complete_and_exit+0x40/0x40
> > > [  193.795907][    C0]  ret_from_fork+0x1f/0x30
> > > [  193.796324][    C0]  </TASK>
> > > [  193.796689][    C0] Modules linked in:
> > > [  193.797189][    C0] ---[ end trace 0000000000000000 ]---
> > > [  193.797635][    C0] RIP: 0010:f2fs_write_end_io+0x727/0x1050
> > > [  193.798182][    C0] Code: 00 00 48 89 f8 48 c1 e8 03 80 3c 18 00 0f
> > > 85 b3 07 00 00 48 8b 44 24 08 4c 8b a8 60 01 00 00 49 8d 7d 30 48 89
> > > f8 48 c1 e8 03 <80> 3c 18 00 0f 85 9c 07 00 00 4d 3b 75 30 0f 0
> > > [  193.799559][    C0] RSP: 0018:ffffc9000042fc78 EFLAGS: 00010216
> > > [  193.799945][    C0] RAX: 0000000000000006 RBX: dffffc0000000000
> > > RCX: 0000000000000100
> > > [  193.800329][    C0] RDX: ffff888013d18000 RSI: ffffffff83a9588d
> > > RDI: 0000000000000030
> > > [  193.800666][    C0] RBP: ffffea000143e740 R08: 0000000000000001
> > > R09: 0000000000000000
> > > [  193.801047][    C0] R10: 0000000000000000 R11: 0000000000000000
> > > R12: ffffea000143e740
> > > [  193.801503][    C0] R13: 0000000000000000 R14: ffff888041423738
> > > R15: 0000000000000000
> > > [  193.802069][    C0] FS:  0000000000000000(0000)
> > > GS:ffff88802ca00000(0000) knlGS:0000000000000000
> > > [  193.802804][    C0] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > [  193.803356][    C0] CR2: 000056056fd87000 CR3: 000000001b546000
> > > CR4: 00000000000006f0
> > > [  193.804046][    C0] Kernel panic - not syncing: Fatal exception in interrupt
> > > [  193.804748][    C0] Kernel Offset: disabled
> > > [  193.805086][    C0] Rebooting in 86400 seconds..
> > > ----------------------------
> > >
> > > If needed, I would provide reproduce.
> > >
> > > Regards,
> > >    butt3rflyh4ck.