* FAILED: patch "[PATCH] f2fs: atomic: fix UAF issue on f2fs_inode_info.atomic_inode" failed to apply to 6.6-stable tree
@ 2026-07-02 13:09 gregkh
2026-07-03 13:31 ` [PATCH 6.6.y] f2fs: atomic: fix UAF issue on f2fs_inode_info.atomic_inode Sasha Levin
0 siblings, 1 reply; 2+ messages in thread
From: gregkh @ 2026-07-02 13:09 UTC (permalink / raw)
To: chao, daehojeong, jaegeuk, s_min.jeong; +Cc: stable
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 e0288584baa5dc41df4a829a023c4c1b33fe53d7
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026070242-unbridle-scallop-a9c6@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From e0288584baa5dc41df4a829a023c4c1b33fe53d7 Mon Sep 17 00:00:00 2001
From: Chao Yu <chao@kernel.org>
Date: Thu, 21 May 2026 10:15:05 +0800
Subject: [PATCH] f2fs: atomic: fix UAF issue on f2fs_inode_info.atomic_inode
- ioctl(F2FS_IOC_GARBAGE_COLLECT_RANGE) - shrink
- f2fs_gc
- gc_data_segment
- ra_data_block(cow_inode)
- mapping = F2FS_I(inode)->atomic_inode->i_mapping
: f2fs_is_cow_file(cow_inode) is true
- f2fs_evict_inode(atomic_inode)
- clear_inode_flag(fi->cow_inode, FI_COW_FILE)
- F2FS_I(fi->cow_inode)->atomic_inode = NULL
...
- truncate_inode_pages_final(atomic_inode)
- f2fs_grab_cache_folio(mapping)
: create folio in atomic_inode->mapping
- clear_inode(atomic_inode)
- BUG_ON(atomic_inode->i_data.nrpages)
We need to add a reference on fi->atomic_inode before using its mapping
field during garbage collection, otherwise, it will cause UAF issue.
Cc: stable@kernel.org
Cc: Daeho Jeong <daehojeong@google.com>
Cc: Sunmin Jeong <s_min.jeong@samsung.com>
Fixes: 3db1de0e582c ("f2fs: change the current atomic write way")
Fixes: f18d00769336 ("f2fs: use meta inode for GC of COW file")
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 99bc59889825..69e0a867219d 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1220,8 +1220,8 @@ static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
static int ra_data_block(struct inode *inode, pgoff_t index)
{
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
- struct address_space *mapping = f2fs_is_cow_file(inode) ?
- F2FS_I(inode)->atomic_inode->i_mapping : inode->i_mapping;
+ struct address_space *mapping = inode->i_mapping;
+ struct inode *atomic_inode = NULL;
struct dnode_of_data dn;
struct folio *folio, *efolio;
struct f2fs_io_info fio = {
@@ -1236,9 +1236,22 @@ static int ra_data_block(struct inode *inode, pgoff_t index)
};
int err = 0;
+ f2fs_down_read(&F2FS_I(inode)->i_sem);
+ if (f2fs_is_cow_file(inode)) {
+ atomic_inode = igrab(F2FS_I(inode)->atomic_inode);
+ if (!atomic_inode) {
+ f2fs_up_read(&F2FS_I(inode)->i_sem);
+ return -EBUSY;
+ }
+ mapping = atomic_inode->i_mapping;
+ }
+ f2fs_up_read(&F2FS_I(inode)->i_sem);
+
folio = f2fs_grab_cache_folio(mapping, index, true);
- if (IS_ERR(folio))
- return PTR_ERR(folio);
+ if (IS_ERR(folio)) {
+ err = PTR_ERR(folio);
+ goto out_iput;
+ }
if (f2fs_lookup_read_extent_cache_block(inode, index,
&dn.data_blkaddr)) {
@@ -1299,11 +1312,16 @@ static int ra_data_block(struct inode *inode, pgoff_t index)
f2fs_update_iostat(sbi, inode, FS_DATA_READ_IO, F2FS_BLKSIZE);
f2fs_update_iostat(sbi, NULL, FS_GDATA_READ_IO, F2FS_BLKSIZE);
+ if (atomic_inode)
+ iput(atomic_inode);
return 0;
put_encrypted_page:
f2fs_put_page(fio.encrypted_page, true);
put_folio:
f2fs_folio_put(folio, true);
+out_iput:
+ if (atomic_inode)
+ iput(atomic_inode);
return err;
}
@@ -1314,8 +1332,8 @@ static int ra_data_block(struct inode *inode, pgoff_t index)
static int move_data_block(struct inode *inode, block_t bidx,
int gc_type, unsigned int segno, int off)
{
- struct address_space *mapping = f2fs_is_cow_file(inode) ?
- F2FS_I(inode)->atomic_inode->i_mapping : inode->i_mapping;
+ struct address_space *mapping = inode->i_mapping;
+ struct inode *atomic_inode = NULL;
struct f2fs_io_info fio = {
.sbi = F2FS_I_SB(inode),
.ino = inode->i_ino,
@@ -1337,10 +1355,23 @@ static int move_data_block(struct inode *inode, block_t bidx,
(fio.sbi->gc_mode != GC_URGENT_HIGH) ?
CURSEG_ALL_DATA_ATGC : CURSEG_COLD_DATA;
+ f2fs_down_read(&F2FS_I(inode)->i_sem);
+ if (f2fs_is_cow_file(inode)) {
+ atomic_inode = igrab(F2FS_I(inode)->atomic_inode);
+ if (!atomic_inode) {
+ f2fs_up_read(&F2FS_I(inode)->i_sem);
+ return -EBUSY;
+ }
+ mapping = atomic_inode->i_mapping;
+ }
+ f2fs_up_read(&F2FS_I(inode)->i_sem);
+
/* do not read out */
folio = f2fs_grab_cache_folio(mapping, bidx, false);
- if (IS_ERR(folio))
- return PTR_ERR(folio);
+ if (IS_ERR(folio)) {
+ err = PTR_ERR(folio);
+ goto out_iput;
+ }
if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
err = -ENOENT;
@@ -1473,6 +1504,9 @@ static int move_data_block(struct inode *inode, block_t bidx,
folio_unlock(folio);
folio_end_dropbehind(folio);
folio_put(folio);
+out_iput:
+ if (atomic_inode)
+ iput(atomic_inode);
return err;
}
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index 1694726122e6..939d75663a40 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -863,10 +863,15 @@ void f2fs_evict_inode(struct inode *inode)
f2fs_abort_atomic_write(inode, true);
if (fi->cow_inode && f2fs_is_cow_file(fi->cow_inode)) {
- clear_inode_flag(fi->cow_inode, FI_COW_FILE);
- F2FS_I(fi->cow_inode)->atomic_inode = NULL;
- iput(fi->cow_inode);
+ struct inode *cow_inode = fi->cow_inode;
+
+ f2fs_down_write(&F2FS_I(cow_inode)->i_sem);
+ clear_inode_flag(cow_inode, FI_COW_FILE);
+ F2FS_I(cow_inode)->atomic_inode = NULL;
fi->cow_inode = NULL;
+ f2fs_up_write(&F2FS_I(cow_inode)->i_sem);
+
+ iput(cow_inode);
}
trace_f2fs_evict_inode(inode);
^ permalink raw reply related [flat|nested] 2+ messages in thread* [PATCH 6.6.y] f2fs: atomic: fix UAF issue on f2fs_inode_info.atomic_inode
2026-07-02 13:09 FAILED: patch "[PATCH] f2fs: atomic: fix UAF issue on f2fs_inode_info.atomic_inode" failed to apply to 6.6-stable tree gregkh
@ 2026-07-03 13:31 ` Sasha Levin
0 siblings, 0 replies; 2+ messages in thread
From: Sasha Levin @ 2026-07-03 13:31 UTC (permalink / raw)
To: stable; +Cc: Chao Yu, stable, Daeho Jeong, Sunmin Jeong, Jaegeuk Kim,
Sasha Levin
From: Chao Yu <chao@kernel.org>
[ Upstream commit e0288584baa5dc41df4a829a023c4c1b33fe53d7 ]
- ioctl(F2FS_IOC_GARBAGE_COLLECT_RANGE) - shrink
- f2fs_gc
- gc_data_segment
- ra_data_block(cow_inode)
- mapping = F2FS_I(inode)->atomic_inode->i_mapping
: f2fs_is_cow_file(cow_inode) is true
- f2fs_evict_inode(atomic_inode)
- clear_inode_flag(fi->cow_inode, FI_COW_FILE)
- F2FS_I(fi->cow_inode)->atomic_inode = NULL
...
- truncate_inode_pages_final(atomic_inode)
- f2fs_grab_cache_folio(mapping)
: create folio in atomic_inode->mapping
- clear_inode(atomic_inode)
- BUG_ON(atomic_inode->i_data.nrpages)
We need to add a reference on fi->atomic_inode before using its mapping
field during garbage collection, otherwise, it will cause UAF issue.
Cc: stable@kernel.org
Cc: Daeho Jeong <daehojeong@google.com>
Cc: Sunmin Jeong <s_min.jeong@samsung.com>
Fixes: 3db1de0e582c ("f2fs: change the current atomic write way")
Fixes: f18d00769336 ("f2fs: use meta inode for GC of COW file")
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/f2fs/gc.c | 50 +++++++++++++++++++++++++++++++++++++++++--------
fs/f2fs/inode.c | 11 ++++++++---
2 files changed, 50 insertions(+), 11 deletions(-)
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 5654608a119235..ac21950f53cd27 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1173,8 +1173,8 @@ static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
static int ra_data_block(struct inode *inode, pgoff_t index)
{
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
- struct address_space *mapping = f2fs_is_cow_file(inode) ?
- F2FS_I(inode)->atomic_inode->i_mapping : inode->i_mapping;
+ struct address_space *mapping = inode->i_mapping;
+ struct inode *atomic_inode = NULL;
struct dnode_of_data dn;
struct page *page;
struct f2fs_io_info fio = {
@@ -1189,9 +1189,22 @@ static int ra_data_block(struct inode *inode, pgoff_t index)
};
int err;
+ f2fs_down_read(&F2FS_I(inode)->i_sem);
+ if (f2fs_is_cow_file(inode)) {
+ atomic_inode = igrab(F2FS_I(inode)->atomic_inode);
+ if (!atomic_inode) {
+ f2fs_up_read(&F2FS_I(inode)->i_sem);
+ return -EBUSY;
+ }
+ mapping = atomic_inode->i_mapping;
+ }
+ f2fs_up_read(&F2FS_I(inode)->i_sem);
+
page = f2fs_grab_cache_page(mapping, index, true);
- if (!page)
- return -ENOMEM;
+ if (!page) {
+ err = -ENOMEM;
+ goto out_iput;
+ }
if (f2fs_lookup_read_extent_cache_block(inode, index,
&dn.data_blkaddr)) {
@@ -1250,11 +1263,16 @@ static int ra_data_block(struct inode *inode, pgoff_t index)
f2fs_update_iostat(sbi, inode, FS_DATA_READ_IO, F2FS_BLKSIZE);
f2fs_update_iostat(sbi, NULL, FS_GDATA_READ_IO, F2FS_BLKSIZE);
+ if (atomic_inode)
+ iput(atomic_inode);
return 0;
put_encrypted_page:
f2fs_put_page(fio.encrypted_page, 1);
put_page:
f2fs_put_page(page, 1);
+out_iput:
+ if (atomic_inode)
+ iput(atomic_inode);
return err;
}
@@ -1265,8 +1283,8 @@ static int ra_data_block(struct inode *inode, pgoff_t index)
static int move_data_block(struct inode *inode, block_t bidx,
int gc_type, unsigned int segno, int off)
{
- struct address_space *mapping = f2fs_is_cow_file(inode) ?
- F2FS_I(inode)->atomic_inode->i_mapping : inode->i_mapping;
+ struct address_space *mapping = inode->i_mapping;
+ struct inode *atomic_inode = NULL;
struct f2fs_io_info fio = {
.sbi = F2FS_I_SB(inode),
.ino = inode->i_ino,
@@ -1288,10 +1306,23 @@ static int move_data_block(struct inode *inode, block_t bidx,
(fio.sbi->gc_mode != GC_URGENT_HIGH) ?
CURSEG_ALL_DATA_ATGC : CURSEG_COLD_DATA;
+ f2fs_down_read(&F2FS_I(inode)->i_sem);
+ if (f2fs_is_cow_file(inode)) {
+ atomic_inode = igrab(F2FS_I(inode)->atomic_inode);
+ if (!atomic_inode) {
+ f2fs_up_read(&F2FS_I(inode)->i_sem);
+ return -EBUSY;
+ }
+ mapping = atomic_inode->i_mapping;
+ }
+ f2fs_up_read(&F2FS_I(inode)->i_sem);
+
/* do not read out */
page = f2fs_grab_cache_page(mapping, bidx, false);
- if (!page)
- return -ENOMEM;
+ if (!page) {
+ err = -ENOMEM;
+ goto out_iput;
+ }
if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
err = -ENOENT;
@@ -1413,6 +1444,9 @@ static int move_data_block(struct inode *inode, block_t bidx,
f2fs_put_dnode(&dn);
out:
f2fs_put_page(page, 1);
+out_iput:
+ if (atomic_inode)
+ iput(atomic_inode);
return err;
}
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index db80b6cad325cf..354960b1ae958c 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -837,10 +837,15 @@ void f2fs_evict_inode(struct inode *inode)
f2fs_abort_atomic_write(inode, true);
if (fi->cow_inode && f2fs_is_cow_file(fi->cow_inode)) {
- clear_inode_flag(fi->cow_inode, FI_COW_FILE);
- F2FS_I(fi->cow_inode)->atomic_inode = NULL;
- iput(fi->cow_inode);
+ struct inode *cow_inode = fi->cow_inode;
+
+ f2fs_down_write(&F2FS_I(cow_inode)->i_sem);
+ clear_inode_flag(cow_inode, FI_COW_FILE);
+ F2FS_I(cow_inode)->atomic_inode = NULL;
fi->cow_inode = NULL;
+ f2fs_up_write(&F2FS_I(cow_inode)->i_sem);
+
+ iput(cow_inode);
}
trace_f2fs_evict_inode(inode);
--
2.53.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
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2026-07-02 13:09 FAILED: patch "[PATCH] f2fs: atomic: fix UAF issue on f2fs_inode_info.atomic_inode" failed to apply to 6.6-stable tree gregkh
2026-07-03 13:31 ` [PATCH 6.6.y] f2fs: atomic: fix UAF issue on f2fs_inode_info.atomic_inode Sasha Levin
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