On 2021/7/23 10:41, Jack Qiu wrote:
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?
I mean whether this bug exists in mainline? Not sure, I just doubt maybe
we have fixed this issue, but forgot to backport it to 4.19 stable kernel.
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 below patch can fix this issue?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=812a95977fd2f0d1f220c716a98
Thanks,
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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