| Message ID | 20250224102923.93758-1-chao@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 986c50f6bca109c6cf362b4e2babcb85aba958f6 |
| Headers | show |
| Series | [f2fs-dev,v2] f2fs: fix to avoid accessing uninitialized curseg | expand |
Jaegeuk, missed to check this patch? On 2/24/25 18:29, Chao Yu wrote: > syzbot reports a f2fs bug as below: > > F2FS-fs (loop3): Stopped filesystem due to reason: 7 > kworker/u8:7: attempt to access beyond end of device > BUG: unable to handle page fault for address: ffffed1604ea3dfa > RIP: 0010:get_ckpt_valid_blocks fs/f2fs/segment.h:361 [inline] > RIP: 0010:has_curseg_enough_space fs/f2fs/segment.h:570 [inline] > RIP: 0010:__get_secs_required fs/f2fs/segment.h:620 [inline] > RIP: 0010:has_not_enough_free_secs fs/f2fs/segment.h:633 [inline] > RIP: 0010:has_enough_free_secs+0x575/0x1660 fs/f2fs/segment.h:649 > <TASK> > f2fs_is_checkpoint_ready fs/f2fs/segment.h:671 [inline] > f2fs_write_inode+0x425/0x540 fs/f2fs/inode.c:791 > write_inode fs/fs-writeback.c:1525 [inline] > __writeback_single_inode+0x708/0x10d0 fs/fs-writeback.c:1745 > writeback_sb_inodes+0x820/0x1360 fs/fs-writeback.c:1976 > wb_writeback+0x413/0xb80 fs/fs-writeback.c:2156 > wb_do_writeback fs/fs-writeback.c:2303 [inline] > wb_workfn+0x410/0x1080 fs/fs-writeback.c:2343 > process_one_work kernel/workqueue.c:3236 [inline] > process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317 > worker_thread+0x870/0xd30 kernel/workqueue.c:3398 > kthread+0x7a9/0x920 kernel/kthread.c:464 > ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > Commit 8b10d3653735 ("f2fs: introduce FAULT_NO_SEGMENT") allows to trigger > no free segment fault in allocator, then it will update curseg->segno to > NULL_SEGNO, though, CP_ERROR_FLAG has been set, f2fs_write_inode() missed > to check the flag, and access invalid curseg->segno directly in below call > path, then resulting in panic: > > - f2fs_write_inode > - f2fs_is_checkpoint_ready > - has_enough_free_secs > - has_not_enough_free_secs > - __get_secs_required > - has_curseg_enough_space > - get_ckpt_valid_blocks > : access invalid curseg->segno > > To avoid this issue, let's: > - check CP_ERROR_FLAG flag in prior to f2fs_is_checkpoint_ready() in > f2fs_write_inode(). > - in has_curseg_enough_space(), save curseg->segno into a temp variable, > and verify its validation before use. > > Fixes: 8b10d3653735 ("f2fs: introduce FAULT_NO_SEGMENT") > Reported-by: syzbot+b6b347b7a4ea1b2e29b6@syzkaller.appspotmail.com > Closes: https://lore.kernel.org/all/67973c2b.050a0220.11b1bb.0089.GAE@google.com > Signed-off-by: Chao Yu <chao@kernel.org> > --- > v2: > - get rid of potential blocking on curseg_mutex > fs/f2fs/inode.c | 7 +++++++ > fs/f2fs/segment.h | 9 ++++++++- > 2 files changed, 15 insertions(+), 1 deletion(-) > > diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c > index d6ad7810df69..6aec752ac098 100644 > --- a/fs/f2fs/inode.c > +++ b/fs/f2fs/inode.c > @@ -793,6 +793,13 @@ int f2fs_write_inode(struct inode *inode, struct writeback_control *wbc) > !is_inode_flag_set(inode, FI_DIRTY_INODE)) > return 0; > > + /* > + * no need to update inode page, ultimately f2fs_evict_inode() will > + * clear dirty status of inode. > + */ > + if (f2fs_cp_error(sbi)) > + return -EIO; > + > if (!f2fs_is_checkpoint_ready(sbi)) { > f2fs_mark_inode_dirty_sync(inode, true); > return -ENOSPC; > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h > index 943be4f1d6d2..0465dc00b349 100644 > --- a/fs/f2fs/segment.h > +++ b/fs/f2fs/segment.h > @@ -559,13 +559,16 @@ static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi, > unsigned int node_blocks, unsigned int data_blocks, > unsigned int dent_blocks) > { > - > unsigned int segno, left_blocks, blocks; > int i; > > /* check current data/node sections in the worst case. */ > for (i = CURSEG_HOT_DATA; i < NR_PERSISTENT_LOG; i++) { > segno = CURSEG_I(sbi, i)->segno; > + > + if (unlikely(segno == NULL_SEGNO)) > + return false; > + > left_blocks = CAP_BLKS_PER_SEC(sbi) - > get_ckpt_valid_blocks(sbi, segno, true); > > @@ -576,6 +579,10 @@ static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi, > > /* check current data section for dentry blocks. */ > segno = CURSEG_I(sbi, CURSEG_HOT_DATA)->segno; > + > + if (unlikely(segno == NULL_SEGNO)) > + return false; > + > left_blocks = CAP_BLKS_PER_SEC(sbi) - > get_ckpt_valid_blocks(sbi, segno, true); > if (dent_blocks > left_blocks)
Hello: This patch was applied to jaegeuk/f2fs.git (dev) by Jaegeuk Kim <jaegeuk@kernel.org>: On Mon, 24 Feb 2025 18:29:23 +0800 you wrote: > syzbot reports a f2fs bug as below: > > F2FS-fs (loop3): Stopped filesystem due to reason: 7 > kworker/u8:7: attempt to access beyond end of device > BUG: unable to handle page fault for address: ffffed1604ea3dfa > RIP: 0010:get_ckpt_valid_blocks fs/f2fs/segment.h:361 [inline] > RIP: 0010:has_curseg_enough_space fs/f2fs/segment.h:570 [inline] > RIP: 0010:__get_secs_required fs/f2fs/segment.h:620 [inline] > RIP: 0010:has_not_enough_free_secs fs/f2fs/segment.h:633 [inline] > RIP: 0010:has_enough_free_secs+0x575/0x1660 fs/f2fs/segment.h:649 > <TASK> > f2fs_is_checkpoint_ready fs/f2fs/segment.h:671 [inline] > f2fs_write_inode+0x425/0x540 fs/f2fs/inode.c:791 > write_inode fs/fs-writeback.c:1525 [inline] > __writeback_single_inode+0x708/0x10d0 fs/fs-writeback.c:1745 > writeback_sb_inodes+0x820/0x1360 fs/fs-writeback.c:1976 > wb_writeback+0x413/0xb80 fs/fs-writeback.c:2156 > wb_do_writeback fs/fs-writeback.c:2303 [inline] > wb_workfn+0x410/0x1080 fs/fs-writeback.c:2343 > process_one_work kernel/workqueue.c:3236 [inline] > process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317 > worker_thread+0x870/0xd30 kernel/workqueue.c:3398 > kthread+0x7a9/0x920 kernel/kthread.c:464 > ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > [...] Here is the summary with links: - [f2fs-dev,v2] f2fs: fix to avoid accessing uninitialized curseg https://git.kernel.org/jaegeuk/f2fs/c/986c50f6bca1 You are awesome, thank you!
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c index d6ad7810df69..6aec752ac098 100644 --- a/fs/f2fs/inode.c +++ b/fs/f2fs/inode.c @@ -793,6 +793,13 @@ int f2fs_write_inode(struct inode *inode, struct writeback_control *wbc) !is_inode_flag_set(inode, FI_DIRTY_INODE)) return 0; + /* + * no need to update inode page, ultimately f2fs_evict_inode() will + * clear dirty status of inode. + */ + if (f2fs_cp_error(sbi)) + return -EIO; + if (!f2fs_is_checkpoint_ready(sbi)) { f2fs_mark_inode_dirty_sync(inode, true); return -ENOSPC; diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index 943be4f1d6d2..0465dc00b349 100644 --- a/fs/f2fs/segment.h +++ b/fs/f2fs/segment.h @@ -559,13 +559,16 @@ static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi, unsigned int node_blocks, unsigned int data_blocks, unsigned int dent_blocks) { - unsigned int segno, left_blocks, blocks; int i; /* check current data/node sections in the worst case. */ for (i = CURSEG_HOT_DATA; i < NR_PERSISTENT_LOG; i++) { segno = CURSEG_I(sbi, i)->segno; + + if (unlikely(segno == NULL_SEGNO)) + return false; + left_blocks = CAP_BLKS_PER_SEC(sbi) - get_ckpt_valid_blocks(sbi, segno, true); @@ -576,6 +579,10 @@ static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi, /* check current data section for dentry blocks. */ segno = CURSEG_I(sbi, CURSEG_HOT_DATA)->segno; + + if (unlikely(segno == NULL_SEGNO)) + return false; + left_blocks = CAP_BLKS_PER_SEC(sbi) - get_ckpt_valid_blocks(sbi, segno, true); if (dent_blocks > left_blocks)
syzbot reports a f2fs bug as below: F2FS-fs (loop3): Stopped filesystem due to reason: 7 kworker/u8:7: attempt to access beyond end of device BUG: unable to handle page fault for address: ffffed1604ea3dfa RIP: 0010:get_ckpt_valid_blocks fs/f2fs/segment.h:361 [inline] RIP: 0010:has_curseg_enough_space fs/f2fs/segment.h:570 [inline] RIP: 0010:__get_secs_required fs/f2fs/segment.h:620 [inline] RIP: 0010:has_not_enough_free_secs fs/f2fs/segment.h:633 [inline] RIP: 0010:has_enough_free_secs+0x575/0x1660 fs/f2fs/segment.h:649 <TASK> f2fs_is_checkpoint_ready fs/f2fs/segment.h:671 [inline] f2fs_write_inode+0x425/0x540 fs/f2fs/inode.c:791 write_inode fs/fs-writeback.c:1525 [inline] __writeback_single_inode+0x708/0x10d0 fs/fs-writeback.c:1745 writeback_sb_inodes+0x820/0x1360 fs/fs-writeback.c:1976 wb_writeback+0x413/0xb80 fs/fs-writeback.c:2156 wb_do_writeback fs/fs-writeback.c:2303 [inline] wb_workfn+0x410/0x1080 fs/fs-writeback.c:2343 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317 worker_thread+0x870/0xd30 kernel/workqueue.c:3398 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Commit 8b10d3653735 ("f2fs: introduce FAULT_NO_SEGMENT") allows to trigger no free segment fault in allocator, then it will update curseg->segno to NULL_SEGNO, though, CP_ERROR_FLAG has been set, f2fs_write_inode() missed to check the flag, and access invalid curseg->segno directly in below call path, then resulting in panic: - f2fs_write_inode - f2fs_is_checkpoint_ready - has_enough_free_secs - has_not_enough_free_secs - __get_secs_required - has_curseg_enough_space - get_ckpt_valid_blocks : access invalid curseg->segno To avoid this issue, let's: - check CP_ERROR_FLAG flag in prior to f2fs_is_checkpoint_ready() in f2fs_write_inode(). - in has_curseg_enough_space(), save curseg->segno into a temp variable, and verify its validation before use. Fixes: 8b10d3653735 ("f2fs: introduce FAULT_NO_SEGMENT") Reported-by: syzbot+b6b347b7a4ea1b2e29b6@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/67973c2b.050a0220.11b1bb.0089.GAE@google.com Signed-off-by: Chao Yu <chao@kernel.org> --- v2: - get rid of potential blocking on curseg_mutex fs/f2fs/inode.c | 7 +++++++ fs/f2fs/segment.h | 9 ++++++++- 2 files changed, 15 insertions(+), 1 deletion(-)