Messages in this thread | | | Date | Fri, 10 May 2024 10:14:19 +0800 | Subject | Re: [PATCH 3/3] f2fs: fix to do sanity check on i_nid for inline_data inode | From | Chao Yu <> |
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On 2024/5/9 23:52, Jaegeuk Kim wrote: > On 05/06, Chao Yu wrote: >> syzbot reports a f2fs bug as below: >> >> ------------[ cut here ]------------ >> kernel BUG at fs/f2fs/inline.c:258! >> CPU: 1 PID: 34 Comm: kworker/u8:2 Not tainted 6.9.0-rc6-syzkaller-00012-g9e4bc4bcae01 #0 >> RIP: 0010:f2fs_write_inline_data+0x781/0x790 fs/f2fs/inline.c:258 >> Call Trace: >> f2fs_write_single_data_page+0xb65/0x1d60 fs/f2fs/data.c:2834 >> f2fs_write_cache_pages fs/f2fs/data.c:3133 [inline] >> __f2fs_write_data_pages fs/f2fs/data.c:3288 [inline] >> f2fs_write_data_pages+0x1efe/0x3a90 fs/f2fs/data.c:3315 >> do_writepages+0x35b/0x870 mm/page-writeback.c:2612 >> __writeback_single_inode+0x165/0x10b0 fs/fs-writeback.c:1650 >> writeback_sb_inodes+0x905/0x1260 fs/fs-writeback.c:1941 >> wb_writeback+0x457/0xce0 fs/fs-writeback.c:2117 >> wb_do_writeback fs/fs-writeback.c:2264 [inline] >> wb_workfn+0x410/0x1090 fs/fs-writeback.c:2304 >> process_one_work kernel/workqueue.c:3254 [inline] >> process_scheduled_works+0xa12/0x17c0 kernel/workqueue.c:3335 >> worker_thread+0x86d/0xd70 kernel/workqueue.c:3416 >> kthread+0x2f2/0x390 kernel/kthread.c:388 >> ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 >> ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 >> >> The root cause is: inline_data inode can be fuzzed, so that there may >> be valid blkaddr in its direct node, once f2fs triggers background GC >> to migrate the block, it will hit f2fs_bug_on() during dirty page >> writeback. >> >> Let's add sanity check on i_nid field for inline_data inode, meanwhile, >> forbid to migrate inline_data inode's data block to fix this issue. >> >> Reported-by: syzbot+848062ba19c8782ca5c8@syzkaller.appspotmail.com >> Closes: https://lore.kernel.org/linux-f2fs-devel/000000000000d103ce06174d7ec3@google.com >> Signed-off-by: Chao Yu <chao@kernel.org> >> --- >> fs/f2fs/f2fs.h | 2 +- >> fs/f2fs/gc.c | 6 ++++++ >> fs/f2fs/inline.c | 17 ++++++++++++++++- >> fs/f2fs/inode.c | 2 +- >> 4 files changed, 24 insertions(+), 3 deletions(-) >> >> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h >> index fced2b7652f4..c876813b5532 100644 >> --- a/fs/f2fs/f2fs.h >> +++ b/fs/f2fs/f2fs.h >> @@ -4146,7 +4146,7 @@ extern struct kmem_cache *f2fs_inode_entry_slab; >> * inline.c >> */ >> bool f2fs_may_inline_data(struct inode *inode); >> -bool f2fs_sanity_check_inline_data(struct inode *inode); >> +bool f2fs_sanity_check_inline_data(struct inode *inode, struct page *ipage); >> bool f2fs_may_inline_dentry(struct inode *inode); >> void f2fs_do_read_inline_data(struct page *page, struct page *ipage); >> void f2fs_truncate_inline_inode(struct inode *inode, >> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c >> index e86c7f01539a..041957750478 100644 >> --- a/fs/f2fs/gc.c >> +++ b/fs/f2fs/gc.c >> @@ -1563,6 +1563,12 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, >> continue; >> } >> >> + if (f2fs_has_inline_data(inode)) { >> + iput(inode); >> + set_sbi_flag(sbi, SBI_NEED_FSCK); >> + continue; > > Any race condtion to get this as false alarm?
Since there is no reproducer for the bug, I doubt it was caused by metadata fuzzing, something like this:
- inline inode has one valid blkaddr in i_addr or in dnode reference by i_nid; - SIT/SSA entry of the block is valid; - background GC migrates the block; - kworker writeback it, and trigger the bug_on().
Thoughts?
Thanks,
> >> + } >> + >> err = f2fs_gc_pinned_control(inode, gc_type, segno); >> if (err == -EAGAIN) { >> iput(inode); >> diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c >> index ac00423f117b..067600fed3d4 100644 >> --- a/fs/f2fs/inline.c >> +++ b/fs/f2fs/inline.c >> @@ -33,11 +33,26 @@ bool f2fs_may_inline_data(struct inode *inode) >> return !f2fs_post_read_required(inode); >> } >> >> -bool f2fs_sanity_check_inline_data(struct inode *inode) >> +static bool has_node_blocks(struct inode *inode, struct page *ipage) >> +{ >> + struct f2fs_inode *ri = F2FS_INODE(ipage); >> + int i; >> + >> + for (i = 0; i < DEF_NIDS_PER_INODE; i++) { >> + if (ri->i_nid[i]) >> + return true; >> + } >> + return false; >> +} >> + >> +bool f2fs_sanity_check_inline_data(struct inode *inode, struct page *ipage) >> { >> if (!f2fs_has_inline_data(inode)) >> return false; >> >> + if (has_node_blocks(inode, ipage)) >> + return false; >> + >> if (!support_inline_data(inode)) >> return true; >> >> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c >> index c26effdce9aa..1423cd27a477 100644 >> --- a/fs/f2fs/inode.c >> +++ b/fs/f2fs/inode.c >> @@ -343,7 +343,7 @@ static bool sanity_check_inode(struct inode *inode, struct page *node_page) >> } >> } >> >> - if (f2fs_sanity_check_inline_data(inode)) { >> + if (f2fs_sanity_check_inline_data(inode, node_page)) { >> f2fs_warn(sbi, "%s: inode (ino=%lx, mode=%u) should not have inline_data, run fsck to fix", >> __func__, inode->i_ino, inode->i_mode); >> return false; >> -- >> 2.40.1
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