On 7/11/23 06:22, Jaegeuk Kim wrote:
> Hit a kernel panic with single device.
>
> [ 148.003511] BUG: kernel NULL pointer dereference, address: 0000000000000058
> [ 148.005630] #PF: supervisor read access in kernel mode
> [ 148.008179] #PF: error_code(0x0000) - not-present page
> [ 148.010593] PGD 0 P4D 0
> [ 148.011867] Oops: 0000 [#1] PREEMPT SMP PTI
> [ 148.014619] CPU: 4 PID: 1905 Comm: umount Tainted: G OE 6.5.0-rc1-custom #19
> [ 148.020358] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
> [ 148.024967] RIP: 0010:destroy_device_list+0x18/0x90 [f2fs]
> [ 148.027688] Code: 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 55 48 89 e5 41 55 41 54 49 89 fc 53 48 8b 87 40 0b 00 00 <48> 8b 78 58 e8 cf 3e 28 cf 41 83 bc 24 3c 0b 00 00 01 7e 4a 41 bd
> [ 148.038517] RSP: 0018:ffffa24e80be3d28 EFLAGS: 00010202
> [ 148.040978] RAX: 0000000000000000 RBX: ffff8bd5503bc800 RCX: 0000000080080006
> [ 148.044292] RDX: 0000000080080007 RSI: ffffdcfe844da200 RDI: ffff8bd55368d000
> [ 148.047688] RBP: ffffa24e80be3d40 R08: ffff8bd553688000 R09: 0000000080080006
> [ 148.051317] R10: ffff8bd5580d4e80 R11: ffff8bd57bd00000 R12: ffff8bd55368d000
> [ 148.054981] R13: 0000000000000000 R14: ffff8bd55368db18 R15: 0000000000000000
> [ 148.058391] FS: 00007fc247124800(0000) GS:ffff8bd57bd00000(0000) knlGS:0000000000000000
> [ 148.062549] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 148.065641] CR2: 0000000000000058 CR3: 0000000001120004 CR4: 0000000000370ee0
> [ 148.069178] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 148.072651] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [ 148.076346] Call Trace:
> [ 148.077641] <TASK>
> [ 148.078839] ? show_regs+0x6a/0x80
> [ 148.080475] ? __die+0x25/0x70
> [ 148.082045] ? page_fault_oops+0x160/0x480
> [ 148.084381] ? check_preempt_wakeup+0x192/0x2f0
> [ 148.086840] ? do_user_addr_fault+0x313/0x680
> [ 148.088999] ? exc_page_fault+0x79/0x180
> [ 148.090899] ? asm_exc_page_fault+0x27/0x30
> [ 148.093114] ? destroy_device_list+0x18/0x90 [f2fs]
> [ 148.095448] f2fs_put_super+0x211/0x410 [f2fs]
> [ 148.097871] ? fscrypt_destroy_keyring+0x110/0x170
> [ 148.100313] generic_shutdown_super+0x84/0x1b0
> [ 148.102582] kill_block_super+0x24/0x50
> [ 148.104697] kill_f2fs_super+0x83/0x100 [f2fs]
> [ 148.106974] deactivate_locked_super+0x35/0xb0
> [ 148.109978] deactivate_super+0x44/0x50
> [ 148.112235] cleanup_mnt+0x105/0x160
> [ 148.114407] __cleanup_mnt+0x12/0x20
> [ 148.116680] task_work_run+0x61/0x90
> [ 148.118961] exit_to_user_mode_prepare+0x18f/0x1a0
> [ 148.121812] syscall_exit_to_user_mode+0x26/0x50
> [ 148.124595] do_syscall_64+0x69/0x90
> [ 148.126616] ? exc_page_fault+0x8a/0x180
> [ 148.128742] entry_SYSCALL_64_after_hwframe+0x6e/0xd8
> [ 148.131521] RIP: 0033:0x7fc246f24a7b
>
> On 07/07, Christoph Hellwig wrote:
>> f2fs_scan_devices reopens the main device since the very beginning, which
>> has always been useless, and also means that we don't pass the right
>> holder for the reopen, which now leads to a warning as the core super.c
>> holder ops aren't passed in for the reopen.
>>
>> Fixes: 3c62be17d4f5 ("f2fs: support multiple devices")
>> Fixes: 0718afd47f70 ("block: introduce holder ops")
>> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
>> ---
>> fs/f2fs/super.c | 20 ++++++++------------
>> 1 file changed, 8 insertions(+), 12 deletions(-)
>>
>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>> index ca31163da00a55..8d11d4a5ec331d 100644
>> --- a/fs/f2fs/super.c
>> +++ b/fs/f2fs/super.c
>> @@ -1560,7 +1560,8 @@ static void destroy_device_list(struct f2fs_sb_info *sbi)
>> {
>> int i;
>>
>> - for (i = 0; i < sbi->s_ndevs; i++) {
>
> #ifdef CONFIG_BLK_DEV_ZONED
>
>> + kvfree(FDEV(0).blkz_seq);
>
> #endif
This should not be needed since for the !CONFIG_BLK_DEV_ZONED case,
FDEV(0).blkz_seq should always be NULL. However, what I think may be missing is
"FDEV(0).blkz_seq = NULL;" after the kvfree() call. No ?
>
>> + for (i = 1; i < sbi->s_ndevs; i++) {
>> blkdev_put(FDEV(i).bdev, sbi->sb->s_type);
>> #ifdef CONFIG_BLK_DEV_ZONED
>> kvfree(FDEV(i).blkz_seq);
>> @@ -4190,16 +4191,12 @@ static int f2fs_scan_devices(struct f2fs_sb_info *sbi)
>> sbi->aligned_blksize = true;
>>
>> for (i = 0; i < max_devices; i++) {
>> -
>> - if (i > 0 && !RDEV(i).path[0])
>> + if (i == 0)
>> + FDEV(0).bdev = sbi->sb->s_bdev;
>> + else if (!RDEV(i).path[0])
>> break;
>>
>> - if (max_devices == 1) {
>> - /* Single zoned block device mount */
>> - FDEV(0).bdev =
>> - blkdev_get_by_dev(sbi->sb->s_bdev->bd_dev, mode,
>> - sbi->sb->s_type, NULL);
>> - } else {
>> + if (max_devices > 1) {
>> /* Multi-device mount */
>> memcpy(FDEV(i).path, RDEV(i).path, MAX_PATH_LEN);
>> FDEV(i).total_segments =
>> @@ -4215,10 +4212,9 @@ static int f2fs_scan_devices(struct f2fs_sb_info *sbi)
>> FDEV(i).end_blk = FDEV(i).start_blk +
>> (FDEV(i).total_segments <<
>> sbi->log_blocks_per_seg) - 1;
>> + FDEV(i).bdev = blkdev_get_by_path(FDEV(i).path,
>> + mode, sbi->sb->s_type, NULL);
>> }
>> - FDEV(i).bdev = blkdev_get_by_path(FDEV(i).path, mode,
>> - sbi->sb->s_type,
>> - NULL);
>> }
>> if (IS_ERR(FDEV(i).bdev))
>> return PTR_ERR(FDEV(i).bdev);
>> --
>> 2.39.2
--
Damien Le Moal
Western Digital Research
