On 2021/7/22 22:05, Chao Yu wrote:
> On 2021/7/22 12:41, Jack Qiu wrote:
>> The root cause is shrink_dcache_sb after sbi has been freed.
>> So call shrink_dcache_sb before free sbi and other resources.
>>
>> ==================================================================
>> BUG: KASAN: use-after-free in f2fs_evict_inode+0x31c/0xde5
>> Read of size 4 at addr ffff8881d97f0d50 by task syz-executor.3/8729
>>
>> PU: 1 PID: 8729 Comm: syz-executor.3 Not tainted
>> 4.19.195-00002-g67dceea04431-dirty #31
>
> Does this bug below to 4.19.195?
>
Yes, I believe ed2e621a95d704e6a4e904cc00524e8cbddda0c2 causes this bug.
git describe --contains ed2e621a95d704e6a4e904cc00524e8cbddda0c2
v3.17-rc4~27^2~17
@@ -1126,6 +1130,13 @@ static int f2fs_fill_super(struct super_block *sb, void
*data, int silent)
brelse(raw_super_buf);
free_sbi:
kfree(sbi); --- free sbi
+
+ /* give only one another chance */
+ if (retry) {
+ retry = !retry;
+ shrink_dcache_sb(sb); --- call f2fs_evict_inode(root inode), it
will access sbi
+ goto try_onemore;
+ }
return err;
}
>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
>> ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31
>> 04/01/2014
>> Call Trace:
>> dump_stack+0xe5/0x14b
>> ? f2fs_evict_inode+0x31c/0xde5
>> print_address_description+0x6c/0x237
>> ? f2fs_evict_inode+0x31c/0xde5
>> kasan_report.cold+0x88/0x2a3
>> f2fs_evict_inode+0x31c/0xde5
>> ? full_proxy_open.cold+0x12/0x12
>> evict+0x2cd/0x5f0
>> iput+0x3d9/0x6f0
>> dentry_unlink_inode+0x273/0x330
>> __dentry_kill+0x340/0x5e0
>> dentry_kill+0xb7/0x740
>> shrink_dentry_list+0x256/0x660
>> shrink_dcache_sb+0x11f/0x1d0
>> ? shrink_dentry_list+0x660/0x660
>> ? __kasan_slab_free+0x144/0x180
>> f2fs_fill_super+0x2a34/0x4a80
>> ? f2fs_sanity_check_ckpt.cold+0x2b6/0x2b6
>> ? wait_for_completion+0x3c0/0x3c0
>> ? set_blocksize+0x230/0x2b0
>> mount_bdev+0x2c1/0x370
>> ? f2fs_sanity_check_ckpt.cold+0x2b6/0x2b6
>> mount_fs+0x4c/0x1c0
>> vfs_kern_mount.part.0+0x60/0x3d0
>> do_mount+0x367/0x2570
>> ? kasan_unpoison_shadow+0x33/0x40
>> ? copy_mount_string+0x40/0x40
>> ? kmem_cache_alloc_trace+0x13f/0x2b0
>> ? _copy_from_user+0x94/0x100
>> ? copy_mount_options+0x1f1/0x2e0
>> ksys_mount+0xa0/0x100
>> __x64_sys_mount+0xbf/0x160
>> do_syscall_64+0xc2/0x190
>> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>> RIP: 0033:0x47938e
>> Code: 48 c7 c1 b4 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84
>> 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01
>> f0 ff ff 73 01 c3 48 c7 c1 b4 ff ff ff f7 d8 64 89 01 48
>> RSP: 002b:00007fed673b6a48 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
>> RAX: ffffffffffffffda RBX: 0000000020000200 RCX: 000000000047938e
>> RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fed673b6aa0
>> RBP: 00007fed673b6ae0 R08: 00007fed673b6ae0 R09: 0000000020000000
>> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020000000
>> R13: 0000000020000100 R14: 00007fed673b6aa0 R15: 0000000020000b00
>>
>> Allocated by task 8729:
>> kasan_kmalloc+0xc2/0xe0
>> kmem_cache_alloc_trace+0x13f/0x2b0
>> f2fs_fill_super+0x124/0x4a80
>> mount_bdev+0x2c1/0x370
>> mount_fs+0x4c/0x1c0
>> vfs_kern_mount.part.0+0x60/0x3d0
>> do_mount+0x367/0x2570
>> ksys_mount+0xa0/0x100
>> __x64_sys_mount+0xbf/0x160
>> do_syscall_64+0xc2/0x190
>> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>>
>> Freed by task 8729:
>> __kasan_slab_free+0x12f/0x180
>> kfree+0xfa/0x2a0
>> f2fs_fill_super+0x2a00/0x4a80
>> mount_bdev+0x2c1/0x370
>> mount_fs+0x4c/0x1c0
>> vfs_kern_mount.part.0+0x60/0x3d0
>> do_mount+0x367/0x2570
>> ksys_mount+0xa0/0x100
>> __x64_sys_mount+0xbf/0x160
>> do_syscall_64+0xc2/0x190
>> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>>
>> Signed-off-by: Jack Qiu <[email protected]>
>> ---
>> fs/f2fs/super.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>> index 8fecd3050ccd..b041625e06ce 100644
>> --- a/fs/f2fs/super.c
>> +++ b/fs/f2fs/super.c
>> @@ -4229,6 +4229,8 @@ static int f2fs_fill_super(struct super_block *sb,
>> void *data, int silent)
>> free_compress_inode:
>> f2fs_destroy_compress_inode(sbi);
>> free_root_inode:
>> + if (retry_cnt > 0 && skip_recovery)
>> + shrink_dcache_sb(sb);
>
> Compare to 4.19, last f2fs adds evict_inodes() before f2fs_unregister_sysfs(),
Can not find *evict_inodes*, could you please elaborate more detail?
> could you please check whether this can fix the issue?
I have run the test more than 1 day w/ this patch, it will fail in 1 hour
before.
I believe this patch can fix *this* issue. But I'm not quite familiar with
shrink_dcache_sb,
maybe I miss other scenario. If you have other comment, please let me know.
Thanks,
>
> Thanks,
>
>> dput(sb->s_root);
>> sb->s_root = NULL;
>> free_node_inode:
>> @@ -4285,7 +4287,6 @@ static int f2fs_fill_super(struct super_block *sb,
>> void *data, int silent)
>> /* give only one another chance */
>> if (retry_cnt > 0 && skip_recovery) {
>> retry_cnt--;
>> - shrink_dcache_sb(sb);
>> goto try_onemore;
>> }
>> return err;
>> --
>> 2.17.1
>>
> .
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