FAILED: patch "[PATCH] nilfs2: ignore non-fatal signals during synchronous log write wait" failed to apply to 6.6-stable tree

FAILED: patch "[PATCH] nilfs2: ignore non-fatal signals during synchronous log write wait" failed to apply to 6.6-stable tree

[Sasha Levin]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 7131aaa74bcc7c9da1f1d1c8724da75c775557a0
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107053051-failed-6.6-7131aaa74bcc@kernel.org' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From 7131aaa74bcc7c9da1f1d1c8724da75c775557a0 Mon Sep 17 00:00:00 2001
From: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Date: Wed, 30 Sep 2026 03:26:54 +0900
Subject: [PATCH] nilfs2: ignore non-fatal signals during synchronous log write
 wait

Based on a syzbot report, Wang Jianjian pointed out that following a
successful directory operation in nilfs_rename(), a synchronous write
requested within nilfs_transaction_commit(), triggered by a sync flag
set by nilfs_commit_chunk(), could be interrupted by a user signal.
This interruption leaves in-memory metadata updates intact while
returning an error, causing inconsistency with the VFS dentry cache and
ultimately triggering a kernel warning.

According to "signal(7)", local disks are not classified as "slow
devices" (such as terminals, FIFOs, or pipes) and their I/O operations
on disk devices are not interrupted by signals.  In kernel space,
waiting for such disk I/O should therefore not be aborted by ordinary
(non-fatal) signals.

Suppress this issue by modifying nilfs_segctor_sync(), which waits for
the log writer thread to complete synchronous writes, to catch only
fatal signals via fatal_signal_pending() and return -EINTR rather than
-ERESTARTSYS.  To complement this change and prevent the wait loop from
busy-looping when schedule() returns immediately due to a pending
non-fatal signal, switch the wait state from TASK_INTERRUPTIBLE to
TASK_KILLABLE.

This serves as an effective interim stabilization measure without
structural changes until a comprehensive fix for metadata consistency
is implemented.

Reported-by: syzbot+f6c7e1f1809f235eeb90@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=f6c7e1f1809f235eeb90
Fixes: 9ff05123e3bf ("nilfs2: segment constructor")
Tested-by: syzbot+f6c7e1f1809f235eeb90@syzkaller.appspotmail.com
Cc: Wang Jianjian <wangjianjian3@huawei.com>
Cc: stable@vger.kernel.org
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
---
 fs/nilfs2/ioctl.c    |  2 +-
 fs/nilfs2/recovery.c |  2 +-
 fs/nilfs2/segment.c  | 10 +++++-----
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index 01a04080ef704..b2b67d6a1f097 100644
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -965,10 +965,10 @@ static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp,
  * Return: 0 on success, or one of the following negative error codes on
  * failure:
  * * %-EFAULT		- Failure during execution of requested operation.
+ * * %-EINTR		- Interrupted.
  * * %-EIO		- I/O error.
  * * %-ENOMEM		- Insufficient memory available.
  * * %-ENOSPC		- No space left on device (only in a panic state).
- * * %-ERESTARTSYS	- Interrupted.
  * * %-EROFS		- Read only filesystem.
  */
 static int nilfs_ioctl_sync(struct inode *inode, struct file *filp,
diff --git a/fs/nilfs2/recovery.c b/fs/nilfs2/recovery.c
index 9a70c28ec94c1..abe4101f7550c 100644
--- a/fs/nilfs2/recovery.c
+++ b/fs/nilfs2/recovery.c
@@ -790,11 +790,11 @@ static void nilfs_abort_roll_forward(struct the_nilfs *nilfs)
  *
  * Return: 0 on success, or one of the following negative error codes on
  * failure:
+ * * %-EINTR		- Interrupted.
  * * %-EINVAL		- Inconsistent filesystem state.
  * * %-EIO		- I/O error.
  * * %-ENOMEM		- Insufficient memory available.
  * * %-ENOSPC		- No space left on device (only in a panic state).
- * * %-ERESTARTSYS	- Interrupted.
  */
 int nilfs_salvage_orphan_logs(struct the_nilfs *nilfs,
 			      struct super_block *sb,
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 2f0e59847d026..af0c3560444f5 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -2259,7 +2259,7 @@ static int nilfs_segctor_sync(struct nilfs_sc_info *sci)
 	wake_up(&sci->sc_wait_daemon);
 
 	for (;;) {
-		set_current_state(TASK_INTERRUPTIBLE);
+		set_current_state(TASK_KILLABLE);
 
 		/*
 		 * Synchronize only while the log writer thread is alive.
@@ -2273,11 +2273,11 @@ static int nilfs_segctor_sync(struct nilfs_sc_info *sci)
 			err = wait_req.err;
 			break;
 		}
-		if (!signal_pending(current)) {
+		if (!fatal_signal_pending(current)) {
 			schedule();
 			continue;
 		}
-		err = -ERESTARTSYS;
+		err = -EINTR;
 		break;
 	}
 	finish_wait(&sci->sc_wait_request, &wait_req.wq);
@@ -2311,10 +2311,10 @@ static void nilfs_segctor_wakeup(struct nilfs_sc_info *sci, int err, bool force)
  *
  * Return: 0 on success, or one of the following negative error codes on
  * failure:
+ * * %-EINTR		- Interrupted.
  * * %-EIO		- I/O error (including metadata corruption).
  * * %-ENOMEM		- Insufficient memory available.
  * * %-ENOSPC		- No space left on device (only in a panic state).
- * * %-ERESTARTSYS	- Interrupted.
  * * %-EROFS		- Read only filesystem.
  */
 int nilfs_construct_segment(struct super_block *sb)
@@ -2341,10 +2341,10 @@ int nilfs_construct_segment(struct super_block *sb)
  *
  * Return: 0 on success, or one of the following negative error codes on
  * failure:
+ * * %-EINTR		- Interrupted.
  * * %-EIO		- I/O error (including metadata corruption).
  * * %-ENOMEM		- Insufficient memory available.
  * * %-ENOSPC		- No space left on device (only in a panic state).
- * * %-ERESTARTSYS	- Interrupted.
  * * %-EROFS		- Read only filesystem.
  */
 int nilfs_construct_dsync_segment(struct super_block *sb, struct inode *inode,
-- 
2.53.0

[PATCH 6.6.y 1/2] nilfs2: correct return value kernel-doc descriptions for the rest

[Sasha Levin]

From: Ryusuke Konishi <konishi.ryusuke@gmail.com>

[ Upstream commit 343d4a33f26d048fde4b02cfc3681f766b3f1b12 ]

Similar to the previous changes to fix return value descriptions, this
fixes the format of the return value descriptions of functions for the
rest.

Link: https://lkml.kernel.org/r/20250110010530.21872-6-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: "Brian G ." <gissf1@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: 7131aaa74bcc ("nilfs2: ignore non-fatal signals during synchronous log write wait")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nilfs2/gcinode.c   | 24 +++++++++-------------
 fs/nilfs2/inode.c     | 12 +++--------
 fs/nilfs2/recovery.c  | 32 +++++++++++------------------
 fs/nilfs2/segbuf.c    | 12 ++---------
 fs/nilfs2/segment.c   | 48 ++++++++++++++++---------------------------
 fs/nilfs2/the_nilfs.c | 12 +++++------
 6 files changed, 50 insertions(+), 90 deletions(-)

diff --git a/fs/nilfs2/gcinode.c b/fs/nilfs2/gcinode.c
index 3a50fe0424770..a2dd5639c4833 100644
--- a/fs/nilfs2/gcinode.c
+++ b/fs/nilfs2/gcinode.c
@@ -46,14 +46,11 @@
  * specified by @pbn to the GC pagecache with the key @blkoff.
  * This function sets @vbn (@pbn if @vbn is zero) in b_blocknr of the buffer.
  *
- * Return Value: On success, 0 is returned. On Error, one of the following
- * negative error code is returned.
- *
- * %-EIO - I/O error.
- *
- * %-ENOMEM - Insufficient amount of memory available.
- *
- * %-ENOENT - The block specified with @pbn does not exist.
+ * Return: 0 on success, or one of the following negative error codes on
+ * failure:
+ * * %-EIO	- I/O error (including metadata corruption).
+ * * %-ENOENT	- The block specified with @pbn does not exist.
+ * * %-ENOMEM	- Insufficient memory available.
  */
 int nilfs_gccache_submit_read_data(struct inode *inode, sector_t blkoff,
 				   sector_t pbn, __u64 vbn,
@@ -114,12 +111,11 @@ int nilfs_gccache_submit_read_data(struct inode *inode, sector_t blkoff,
  * specified by @vbn to the GC pagecache.  @pbn can be supplied by the
  * caller to avoid translation of the disk block address.
  *
- * Return Value: On success, 0 is returned. On Error, one of the following
- * negative error code is returned.
- *
- * %-EIO - I/O error.
- *
- * %-ENOMEM - Insufficient amount of memory available.
+ * Return: 0 on success, or one of the following negative error codes on
+ * failure:
+ * * %-EIO	- I/O error (including metadata corruption).
+ * * %-ENOENT	- Invalid virtual block address.
+ * * %-ENOMEM	- Insufficient memory available.
  */
 int nilfs_gccache_submit_read_node(struct inode *inode, sector_t pbn,
 				   __u64 vbn, struct buffer_head **out_bh)
diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index 410da542a3b90..5e17408c80ae6 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -676,10 +676,7 @@ struct inode *nilfs_iget_for_gc(struct super_block *sb, unsigned long ino,
  * or does nothing if the inode already has it.  This function allocates
  * an additional inode to maintain page cache of B-tree nodes one-on-one.
  *
- * Return Value: On success, 0 is returned. On errors, one of the following
- * negative error code is returned.
- *
- * %-ENOMEM - Insufficient memory available.
+ * Return: 0 on success, or %-ENOMEM if memory is insufficient.
  */
 int nilfs_attach_btree_node_cache(struct inode *inode)
 {
@@ -740,11 +737,8 @@ void nilfs_detach_btree_node_cache(struct inode *inode)
  * in one inode and the one for b-tree node pages is set up in the
  * other inode, which is attached to the former inode.
  *
- * Return Value: On success, a pointer to the inode for data pages is
- * returned. On errors, one of the following negative error code is returned
- * in a pointer type.
- *
- * %-ENOMEM - Insufficient memory available.
+ * Return: a pointer to the inode for data pages on success, or %-ENOMEM
+ * if memory is insufficient.
  */
 struct inode *nilfs_iget_for_shadow(struct inode *inode)
 {
diff --git a/fs/nilfs2/recovery.c b/fs/nilfs2/recovery.c
index ce30b51ac593c..b5207e4c50007 100644
--- a/fs/nilfs2/recovery.c
+++ b/fs/nilfs2/recovery.c
@@ -741,18 +741,13 @@ static void nilfs_abort_roll_forward(struct the_nilfs *nilfs)
  * @sb: super block instance
  * @ri: pointer to a nilfs_recovery_info struct to store search results.
  *
- * Return Value: On success, 0 is returned.  On error, one of the following
- * negative error code is returned.
- *
- * %-EINVAL - Inconsistent filesystem state.
- *
- * %-EIO - I/O error
- *
- * %-ENOSPC - No space left on device (only in a panic state).
- *
- * %-ERESTARTSYS - Interrupted.
- *
- * %-ENOMEM - Insufficient memory available.
+ * Return: 0 on success, or one of the following negative error codes on
+ * failure:
+ * * %-EINVAL		- Inconsistent filesystem state.
+ * * %-EIO		- I/O error.
+ * * %-ENOMEM		- Insufficient memory available.
+ * * %-ENOSPC		- No space left on device (only in a panic state).
+ * * %-ERESTARTSYS	- Interrupted.
  */
 int nilfs_salvage_orphan_logs(struct the_nilfs *nilfs,
 			      struct super_block *sb,
@@ -817,14 +812,11 @@ int nilfs_salvage_orphan_logs(struct the_nilfs *nilfs,
  * segment pointed by the superblock.  It sets up struct the_nilfs through
  * this search. It fills nilfs_recovery_info (ri) required for recovery.
  *
- * Return Value: On success, 0 is returned.  On error, one of the following
- * negative error code is returned.
- *
- * %-EINVAL - No valid segment found
- *
- * %-EIO - I/O error
- *
- * %-ENOMEM - Insufficient memory available.
+ * Return: 0 on success, or one of the following negative error codes on
+ * failure:
+ * * %-EINVAL	- No valid segment found.
+ * * %-EIO	- I/O error.
+ * * %-ENOMEM	- Insufficient memory available.
  */
 int nilfs_search_super_root(struct the_nilfs *nilfs,
 			    struct nilfs_recovery_info *ri)
diff --git a/fs/nilfs2/segbuf.c b/fs/nilfs2/segbuf.c
index 6e59dc19a7324..7416fb6e3fd4b 100644
--- a/fs/nilfs2/segbuf.c
+++ b/fs/nilfs2/segbuf.c
@@ -403,12 +403,7 @@ static int nilfs_segbuf_submit_bh(struct nilfs_segment_buffer *segbuf,
  * @segbuf: buffer storing a log to be written
  * @nilfs: nilfs object
  *
- * Return Value: On Success, 0 is returned. On Error, one of the following
- * negative error code is returned.
- *
- * %-EIO - I/O error
- *
- * %-ENOMEM - Insufficient memory available.
+ * Return: Always 0.
  */
 static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
 			      struct the_nilfs *nilfs)
@@ -449,10 +444,7 @@ static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
  * nilfs_segbuf_wait - wait for completion of requested BIOs
  * @segbuf: segment buffer
  *
- * Return Value: On Success, 0 is returned. On Error, one of the following
- * negative error code is returned.
- *
- * %-EIO - I/O error
+ * Return: 0 on success, or %-EIO if I/O error is detected.
  */
 static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf)
 {
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index be67304825201..ab2359959b566 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -191,12 +191,10 @@ static int nilfs_prepare_segment_lock(struct super_block *sb,
  * When @vacancy_check flag is set, this function will check the amount of
  * free space, and will wait for the GC to reclaim disk space if low capacity.
  *
- * Return Value: On success, 0 is returned. On error, one of the following
- * negative error code is returned.
- *
- * %-ENOMEM - Insufficient memory available.
- *
- * %-ENOSPC - No space left on device
+ * Return: 0 on success, or one of the following negative error codes on
+ * failure:
+ * * %-ENOMEM	- Insufficient memory available.
+ * * %-ENOSPC	- No space left on device (if checking free space).
  */
 int nilfs_transaction_begin(struct super_block *sb,
 			    struct nilfs_transaction_info *ti,
@@ -2295,18 +2293,13 @@ static void nilfs_segctor_wakeup(struct nilfs_sc_info *sci, int err, bool force)
  * nilfs_construct_segment - construct a logical segment
  * @sb: super block
  *
- * Return Value: On success, 0 is returned. On errors, one of the following
- * negative error code is returned.
- *
- * %-EROFS - Read only filesystem.
- *
- * %-EIO - I/O error
- *
- * %-ENOSPC - No space left on device (only in a panic state).
- *
- * %-ERESTARTSYS - Interrupted.
- *
- * %-ENOMEM - Insufficient memory available.
+ * Return: 0 on success, or one of the following negative error codes on
+ * failure:
+ * * %-EIO		- I/O error (including metadata corruption).
+ * * %-ENOMEM		- Insufficient memory available.
+ * * %-ENOSPC		- No space left on device (only in a panic state).
+ * * %-ERESTARTSYS	- Interrupted.
+ * * %-EROFS		- Read only filesystem.
  */
 int nilfs_construct_segment(struct super_block *sb)
 {
@@ -2330,18 +2323,13 @@ int nilfs_construct_segment(struct super_block *sb)
  * @start: start byte offset
  * @end: end byte offset (inclusive)
  *
- * Return Value: On success, 0 is returned. On errors, one of the following
- * negative error code is returned.
- *
- * %-EROFS - Read only filesystem.
- *
- * %-EIO - I/O error
- *
- * %-ENOSPC - No space left on device (only in a panic state).
- *
- * %-ERESTARTSYS - Interrupted.
- *
- * %-ENOMEM - Insufficient memory available.
+ * Return: 0 on success, or one of the following negative error codes on
+ * failure:
+ * * %-EIO		- I/O error (including metadata corruption).
+ * * %-ENOMEM		- Insufficient memory available.
+ * * %-ENOSPC		- No space left on device (only in a panic state).
+ * * %-ERESTARTSYS	- Interrupted.
+ * * %-EROFS		- Read only filesystem.
  */
 int nilfs_construct_dsync_segment(struct super_block *sb, struct inode *inode,
 				  loff_t start, loff_t end)
diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index f9b10b4e22c01..013aea9dc355d 100644
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -50,8 +50,8 @@ void nilfs_set_last_segment(struct the_nilfs *nilfs,
  * alloc_nilfs - allocate a nilfs object
  * @sb: super block instance
  *
- * Return Value: On success, pointer to the_nilfs is returned.
- * On error, NULL is returned.
+ * Return: a pointer to the allocated nilfs object on success, or NULL on
+ * failure.
  */
 struct the_nilfs *alloc_nilfs(struct super_block *sb)
 {
@@ -202,8 +202,7 @@ static int nilfs_store_log_cursor(struct the_nilfs *nilfs,
  * exponent information written in @sbp and stores it in @blocksize,
  * or aborts with an error message if it's too large.
  *
- * Return Value: On success, 0 is returned. If the block size is too
- * large, -EINVAL is returned.
+ * Return: 0 on success, or %-EINVAL if the block size is too large.
  */
 static int nilfs_get_blocksize(struct super_block *sb,
 			       struct nilfs_super_block *sbp, int *blocksize)
@@ -546,7 +545,7 @@ static int nilfs_valid_sb(struct nilfs_super_block *sbp)
  * area, or if the parameters themselves are not normal, it is
  * determined to be invalid.
  *
- * Return Value: true if invalid, false if valid.
+ * Return: true if invalid, false if valid.
  */
 static bool nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
 {
@@ -677,8 +676,7 @@ static int nilfs_load_super_block(struct the_nilfs *nilfs,
  * reading the super block, getting disk layout information, initializing
  * shared fields in the_nilfs).
  *
- * Return Value: On success, 0 is returned. On error, a negative error
- * code is returned.
+ * Return: 0 on success, or a negative error code on failure.
  */
 int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data)
 {
-- 
2.53.0

[PATCH 6.6.y 2/2] nilfs2: ignore non-fatal signals during synchronous log write wait

[Sasha Levin]

From: Ryusuke Konishi <konishi.ryusuke@gmail.com>

[ Upstream commit 7131aaa74bcc7c9da1f1d1c8724da75c775557a0 ]

Based on a syzbot report, Wang Jianjian pointed out that following a
successful directory operation in nilfs_rename(), a synchronous write
requested within nilfs_transaction_commit(), triggered by a sync flag
set by nilfs_commit_chunk(), could be interrupted by a user signal.
This interruption leaves in-memory metadata updates intact while
returning an error, causing inconsistency with the VFS dentry cache and
ultimately triggering a kernel warning.

According to "signal(7)", local disks are not classified as "slow
devices" (such as terminals, FIFOs, or pipes) and their I/O operations
on disk devices are not interrupted by signals.  In kernel space,
waiting for such disk I/O should therefore not be aborted by ordinary
(non-fatal) signals.

Suppress this issue by modifying nilfs_segctor_sync(), which waits for
the log writer thread to complete synchronous writes, to catch only
fatal signals via fatal_signal_pending() and return -EINTR rather than
-ERESTARTSYS.  To complement this change and prevent the wait loop from
busy-looping when schedule() returns immediately due to a pending
non-fatal signal, switch the wait state from TASK_INTERRUPTIBLE to
TASK_KILLABLE.

This serves as an effective interim stabilization measure without
structural changes until a comprehensive fix for metadata consistency
is implemented.

Reported-by: syzbot+f6c7e1f1809f235eeb90@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=f6c7e1f1809f235eeb90
Fixes: 9ff05123e3bf ("nilfs2: segment constructor")
Tested-by: syzbot+f6c7e1f1809f235eeb90@syzkaller.appspotmail.com
Cc: Wang Jianjian <wangjianjian3@huawei.com>
Cc: stable@vger.kernel.org
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nilfs2/ioctl.c    |  2 +-
 fs/nilfs2/recovery.c |  2 +-
 fs/nilfs2/segment.c  | 10 +++++-----
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index f8c53a411d549..d15d88571fe27 100644
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -960,10 +960,10 @@ static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp,
  * Return: 0 on success, or one of the following negative error codes on
  * failure:
  * * %-EFAULT		- Failure during execution of requested operation.
+ * * %-EINTR		- Interrupted.
  * * %-EIO		- I/O error.
  * * %-ENOMEM		- Insufficient memory available.
  * * %-ENOSPC		- No space left on device (only in a panic state).
- * * %-ERESTARTSYS	- Interrupted.
  * * %-EROFS		- Read only filesystem.
  */
 static int nilfs_ioctl_sync(struct inode *inode, struct file *filp,
diff --git a/fs/nilfs2/recovery.c b/fs/nilfs2/recovery.c
index b5207e4c50007..af1b2a6a93db7 100644
--- a/fs/nilfs2/recovery.c
+++ b/fs/nilfs2/recovery.c
@@ -743,11 +743,11 @@ static void nilfs_abort_roll_forward(struct the_nilfs *nilfs)
  *
  * Return: 0 on success, or one of the following negative error codes on
  * failure:
+ * * %-EINTR		- Interrupted.
  * * %-EINVAL		- Inconsistent filesystem state.
  * * %-EIO		- I/O error.
  * * %-ENOMEM		- Insufficient memory available.
  * * %-ENOSPC		- No space left on device (only in a panic state).
- * * %-ERESTARTSYS	- Interrupted.
  */
 int nilfs_salvage_orphan_logs(struct the_nilfs *nilfs,
 			      struct super_block *sb,
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index ab2359959b566..5c7802de2679b 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -2243,7 +2243,7 @@ static int nilfs_segctor_sync(struct nilfs_sc_info *sci)
 	wake_up(&sci->sc_wait_daemon);
 
 	for (;;) {
-		set_current_state(TASK_INTERRUPTIBLE);
+		set_current_state(TASK_KILLABLE);
 
 		/*
 		 * Synchronize only while the log writer thread is alive.
@@ -2257,11 +2257,11 @@ static int nilfs_segctor_sync(struct nilfs_sc_info *sci)
 			err = wait_req.err;
 			break;
 		}
-		if (!signal_pending(current)) {
+		if (!fatal_signal_pending(current)) {
 			schedule();
 			continue;
 		}
-		err = -ERESTARTSYS;
+		err = -EINTR;
 		break;
 	}
 	finish_wait(&sci->sc_wait_request, &wait_req.wq);
@@ -2295,10 +2295,10 @@ static void nilfs_segctor_wakeup(struct nilfs_sc_info *sci, int err, bool force)
  *
  * Return: 0 on success, or one of the following negative error codes on
  * failure:
+ * * %-EINTR		- Interrupted.
  * * %-EIO		- I/O error (including metadata corruption).
  * * %-ENOMEM		- Insufficient memory available.
  * * %-ENOSPC		- No space left on device (only in a panic state).
- * * %-ERESTARTSYS	- Interrupted.
  * * %-EROFS		- Read only filesystem.
  */
 int nilfs_construct_segment(struct super_block *sb)
@@ -2325,10 +2325,10 @@ int nilfs_construct_segment(struct super_block *sb)
  *
  * Return: 0 on success, or one of the following negative error codes on
  * failure:
+ * * %-EINTR		- Interrupted.
  * * %-EIO		- I/O error (including metadata corruption).
  * * %-ENOMEM		- Insufficient memory available.
  * * %-ENOSPC		- No space left on device (only in a panic state).
- * * %-ERESTARTSYS	- Interrupted.
  * * %-EROFS		- Read only filesystem.
  */
 int nilfs_construct_dsync_segment(struct super_block *sb, struct inode *inode,
-- 
2.53.0

[PATCH 6.6.y] nilfs2: ignore non-fatal signals during synchronous log write wait

[Wang Jianjian]

From: Ryusuke Konishi <konishi.ryusuke@gmail.com>

Based on a syzbot report, Wang Jianjian pointed out that following a
successful directory operation in nilfs_rename(), a synchronous write
requested within nilfs_transaction_commit(), triggered by a sync flag
set by nilfs_commit_chunk(), could be interrupted by a user signal.
This interruption leaves in-memory metadata updates intact while
returning an error, causing inconsistency with the VFS dentry cache and
ultimately triggering a kernel warning.

According to "signal(7)", local disks are not classified as "slow
devices" (such as terminals, FIFOs, or pipes) and their I/O operations
on disk devices are not interrupted by signals.  In kernel space,
waiting for such disk I/O should therefore not be aborted by ordinary
(non-fatal) signals.

Suppress this issue by modifying nilfs_segctor_sync(), which waits for
the log writer thread to complete synchronous writes, to catch only
fatal signals via fatal_signal_pending() and return -EINTR rather than
-ERESTARTSYS.  To complement this change and prevent the wait loop from
busy-looping when schedule() returns immediately due to a pending
non-fatal signal, switch the wait state from TASK_INTERRUPTIBLE to
TASK_KILLABLE.

This serves as an effective interim stabilization measure without
structural changes until a comprehensive fix for metadata consistency
is implemented.

Reported-by: syzbot+f6c7e1f1809f235eeb90@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=f6c7e1f1809f235eeb90
Fixes: 9ff05123e3bf ("nilfs2: segment constructor")
Tested-by: syzbot+f6c7e1f1809f235eeb90@syzkaller.appspotmail.com
Cc: Wang Jianjian <wangjianjian3@huawei.com>
Cc: stable@vger.kernel.org
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
(cherry picked from commit 7131aaa74bcc7c9da1f1d1c8724da75c775557a0)
---
 fs/nilfs2/ioctl.c    |  2 +-
 fs/nilfs2/recovery.c |  4 ++--
 fs/nilfs2/segment.c  | 14 +++++++-------
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index f8c53a411d54..d15d88571fe2 100644
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -960,10 +960,10 @@ static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp,
  * Return: 0 on success, or one of the following negative error codes on
  * failure:
  * * %-EFAULT		- Failure during execution of requested operation.
+ * * %-EINTR		- Interrupted.
  * * %-EIO		- I/O error.
  * * %-ENOMEM		- Insufficient memory available.
  * * %-ENOSPC		- No space left on device (only in a panic state).
- * * %-ERESTARTSYS	- Interrupted.
  * * %-EROFS		- Read only filesystem.
  */
 static int nilfs_ioctl_sync(struct inode *inode, struct file *filp,
diff --git a/fs/nilfs2/recovery.c b/fs/nilfs2/recovery.c
index ce30b51ac593..249be54f7732 100644
--- a/fs/nilfs2/recovery.c
+++ b/fs/nilfs2/recovery.c
@@ -744,14 +744,14 @@ static void nilfs_abort_roll_forward(struct the_nilfs *nilfs)
  * Return Value: On success, 0 is returned.  On error, one of the following
  * negative error code is returned.
  *
+ * %-EINTR - Interrupted.
+ *
  * %-EINVAL - Inconsistent filesystem state.
  *
  * %-EIO - I/O error
  *
  * %-ENOSPC - No space left on device (only in a panic state).
  *
- * %-ERESTARTSYS - Interrupted.
- *
  * %-ENOMEM - Insufficient memory available.
  */
 int nilfs_salvage_orphan_logs(struct the_nilfs *nilfs,
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index be6730482520..be774d69ae23 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -2245,7 +2245,7 @@ static int nilfs_segctor_sync(struct nilfs_sc_info *sci)
 	wake_up(&sci->sc_wait_daemon);
 
 	for (;;) {
-		set_current_state(TASK_INTERRUPTIBLE);
+		set_current_state(TASK_KILLABLE);
 
 		/*
 		 * Synchronize only while the log writer thread is alive.
@@ -2259,11 +2259,11 @@ static int nilfs_segctor_sync(struct nilfs_sc_info *sci)
 			err = wait_req.err;
 			break;
 		}
-		if (!signal_pending(current)) {
+		if (!fatal_signal_pending(current)) {
 			schedule();
 			continue;
 		}
-		err = -ERESTARTSYS;
+		err = -EINTR;
 		break;
 	}
 	finish_wait(&sci->sc_wait_request, &wait_req.wq);
@@ -2298,14 +2298,14 @@ static void nilfs_segctor_wakeup(struct nilfs_sc_info *sci, int err, bool force)
  * Return Value: On success, 0 is returned. On errors, one of the following
  * negative error code is returned.
  *
+ * %-EINTR - Interrupted.
+ *
  * %-EROFS - Read only filesystem.
  *
  * %-EIO - I/O error
  *
  * %-ENOSPC - No space left on device (only in a panic state).
  *
- * %-ERESTARTSYS - Interrupted.
- *
  * %-ENOMEM - Insufficient memory available.
  */
 int nilfs_construct_segment(struct super_block *sb)
@@ -2333,14 +2333,14 @@ int nilfs_construct_segment(struct super_block *sb)
  * Return Value: On success, 0 is returned. On errors, one of the following
  * negative error code is returned.
  *
+ * %-EINTR - Interrupted.
+ *
  * %-EROFS - Read only filesystem.
  *
  * %-EIO - I/O error
  *
  * %-ENOSPC - No space left on device (only in a panic state).
  *
- * %-ERESTARTSYS - Interrupted.
- *
  * %-ENOMEM - Insufficient memory available.
  */
 int nilfs_construct_dsync_segment(struct super_block *sb, struct inode *inode,
-- 
2.34.1