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commit b3a033e3ecd3471248d474ef263aadc0059e516a upstream.
Syzbot reported that page_symlink(), called by nilfs_symlink(), triggers
memory reclamation involving the filesystem layer, which can result in
circular lock dependencies among the reader/writer semaphore
nilfs->ns_segctor_sem, s_writers percpu_rwsem (intwrite) and the
fs_reclaim pseudo lock.
This is because after commit 21fc61c73c39 ("don't put symlink bodies in
pagecache into highmem"), the gfp flags of the page cache for symbolic
links are overwritten to GFP_KERNEL via inode_nohighmem().
This is not a problem for symlinks read from the backing device, because
the __GFP_FS flag is dropped after inode_nohighmem() is called. However,
when a new symlink is created with nilfs_symlink(), the gfp flags remain
overwritten to GFP_KERNEL. Then, memory allocation called from
page_symlink() etc. triggers memory reclamation including the FS layer,
which may call nilfs_evict_inode() or nilfs_dirty_inode(). And these can
cause a deadlock if they are called while nilfs->ns_segctor_sem is held:
Fix this issue by dropping the __GFP_FS flag from the page cache GFP flags
of newly created symlinks in the same way that nilfs_new_inode() and
__nilfs_read_inode() do, as a workaround until we adopt nofs allocation
scope consistently or improve the locking constraints.
Link: https://lkml.kernel.org/r/20241020050003.4308-1-konishi.ryusuke@gmail.com
Fixes: 21fc61c73c39 ("don't put symlink bodies in pagecache into highmem")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+9ef37ac20608f4836256@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=9ef37ac20608f4836256
Tested-by: syzbot+9ef37ac20608f4836256@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 41e192ad2779cae0102879612dfe46726e4396aa upstream.
Syzbot reported that in directory operations after nilfs2 detects
filesystem corruption and degrades to read-only,
__block_write_begin_int(), which is called to prepare block writes, may
fail the BUG_ON check for accesses exceeding the folio/page size,
triggering a kernel bug.
This was found to be because the "checked" flag of a page/folio was not
cleared when it was discarded by nilfs2's own routine, which causes the
sanity check of directory entries to be skipped when the directory
page/folio is reloaded. So, fix that.
This was necessary when the use of nilfs2's own page discard routine was
applied to more than just metadata files.
Link: https://lkml.kernel.org/r/20241017193359.5051-1-konishi.ryusuke@gmail.com
Fixes: 8c26c4e2694a ("nilfs2: fix issue with flush kernel thread after remount in RO mode because of driver's internal error or metadata corruption")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+d6ca2daf692c7a82f959@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=d6ca2daf692c7a82f959
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 6ed469df0bfbef3e4b44fca954a781919db9f7ab upstream.
Syzbot reported that after nilfs2 reads a corrupted file system image
and degrades to read-only, the BUG_ON check for the buffer delay flag
in submit_bh_wbc() may fail, causing a kernel bug.
This is because the buffer delay flag is not cleared when clearing the
buffer state flags to discard a page/folio or a buffer head. So, fix
this.
This became necessary when the use of nilfs2's own page clear routine
was expanded. This state inconsistency does not occur if the buffer
is written normally by log writing.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Link: https://lore.kernel.org/r/20241015213300.7114-1-konishi.ryusuke@gmail.com
Fixes: 8c26c4e2694a ("nilfs2: fix issue with flush kernel thread after remount in RO mode because of driver's internal error or metadata corruption")
Reported-by: syzbot+985ada84bf055a575c07@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=985ada84bf055a575c07
Cc: stable@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 08cfa12adf888db98879dbd735bc741360a34168 upstream.
Syzbot reported that a task hang occurs in vcs_open() during a fuzzing
test for nilfs2.
The root cause of this problem is that in nilfs_find_entry(), which
searches for directory entries, ignores errors when loading a directory
page/folio via nilfs_get_folio() fails.
If the filesystem images is corrupted, and the i_size of the directory
inode is large, and the directory page/folio is successfully read but
fails the sanity check, for example when it is zero-filled,
nilfs_check_folio() may continue to spit out error messages in bursts.
Fix this issue by propagating the error to the callers when loading a
page/folio fails in nilfs_find_entry().
The current interface of nilfs_find_entry() and its callers is outdated
and cannot propagate error codes such as -EIO and -ENOMEM returned via
nilfs_find_entry(), so fix it together.
Link: https://lkml.kernel.org/r/20241004033640.6841-1-konishi.ryusuke@gmail.com
Fixes: 2ba466d74ed7 ("nilfs2: directory entry operations")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: Lizhi Xu <lizhi.xu@windriver.com>
Closes: https://lkml.kernel.org/r/20240927013806.3577931-1-lizhi.xu@windriver.com
Reported-by: syzbot+8a192e8d090fa9a31135@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=8a192e8d090fa9a31135
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit f9c96351aa6718b42a9f42eaf7adce0356bdb5e8 ]
The function nilfs_btree_check_delete(), which checks whether degeneration
to direct mapping occurs before deleting a b-tree entry, causes memory
access outside the block buffer when retrieving the maximum key if the
root node has no entries.
This does not usually happen because b-tree mappings with 0 child nodes
are never created by mkfs.nilfs2 or nilfs2 itself. However, it can happen
if the b-tree root node read from a device is configured that way, so fix
this potential issue by adding a check for that case.
Link: https://lkml.kernel.org/r/20240904081401.16682-4-konishi.ryusuke@gmail.com
Fixes: 17c76b0104e4 ("nilfs2: B-tree based block mapping")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Lizhi Xu <lizhi.xu@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 111b812d3662f3a1b831d19208f83aa711583fe6 ]
Due to the nature of b-trees, nilfs2 itself and admin tools such as
mkfs.nilfs2 will never create an intermediate b-tree node block with 0
child nodes, nor will they delete (key, pointer)-entries that would result
in such a state. However, it is possible that a b-tree node block is
corrupted on the backing device and is read with 0 child nodes.
Because operation is not guaranteed if the number of child nodes is 0 for
intermediate node blocks other than the root node, modify
nilfs_btree_node_broken(), which performs sanity checks when reading a
b-tree node block, so that such cases will be judged as metadata
corruption.
Link: https://lkml.kernel.org/r/20240904081401.16682-3-konishi.ryusuke@gmail.com
Fixes: 17c76b0104e4 ("nilfs2: B-tree based block mapping")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Lizhi Xu <lizhi.xu@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 9403001ad65ae4f4c5de368bdda3a0636b51d51a ]
Patch series "nilfs2: fix potential issues with empty b-tree nodes".
This series addresses three potential issues with empty b-tree nodes that
can occur with corrupted filesystem images, including one recently
discovered by syzbot.
This patch (of 3):
If a b-tree is broken on the device, and the b-tree height is greater than
2 (the level of the root node is greater than 1) even if the number of
child nodes of the b-tree root is 0, a NULL pointer dereference occurs in
nilfs_btree_prepare_insert(), which is called from nilfs_btree_insert().
This is because, when the number of child nodes of the b-tree root is 0,
nilfs_btree_do_lookup() does not set the block buffer head in any of
path[x].bp_bh, leaving it as the initial value of NULL, but if the level
of the b-tree root node is greater than 1, nilfs_btree_get_nonroot_node(),
which accesses the buffer memory of path[x].bp_bh, is called.
Fix this issue by adding a check to nilfs_btree_root_broken(), which
performs sanity checks when reading the root node from the device, to
detect this inconsistency.
Thanks to Lizhi Xu for trying to solve the bug and clarifying the cause
early on.
Link: https://lkml.kernel.org/r/20240904081401.16682-1-konishi.ryusuke@gmail.com
Link: https://lkml.kernel.org/r/20240902084101.138971-1-lizhi.xu@windriver.com
Link: https://lkml.kernel.org/r/20240904081401.16682-2-konishi.ryusuke@gmail.com
Fixes: 17c76b0104e4 ("nilfs2: B-tree based block mapping")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+9bff4c7b992038a7409f@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=9bff4c7b992038a7409f
Cc: Lizhi Xu <lizhi.xu@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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After commit a694291a6211 ("nilfs2: separate wait function from
nilfs_segctor_write") was applied, the log writing function
nilfs_segctor_do_construct() was able to issue I/O requests continuously
even if user data blocks were split into multiple logs across segments,
but two potential flaws were introduced in its error handling.
First, if nilfs_segctor_begin_construction() fails while creating the
second or subsequent logs, the log writing function returns without
calling nilfs_segctor_abort_construction(), so the writeback flag set on
pages/folios will remain uncleared. This causes page cache operations to
hang waiting for the writeback flag. For example,
truncate_inode_pages_final(), which is called via nilfs_evict_inode() when
an inode is evicted from memory, will hang.
Second, the NILFS_I_COLLECTED flag set on normal inodes remain uncleared.
As a result, if the next log write involves checkpoint creation, that's
fine, but if a partial log write is performed that does not, inodes with
NILFS_I_COLLECTED set are erroneously removed from the "sc_dirty_files"
list, and their data and b-tree blocks may not be written to the device,
corrupting the block mapping.
Fix these issues by uniformly calling nilfs_segctor_abort_construction()
on failure of each step in the loop in nilfs_segctor_do_construct(),
having it clean up logs and segment usages according to progress, and
correcting the conditions for calling nilfs_redirty_inodes() to ensure
that the NILFS_I_COLLECTED flag is cleared.
Link: https://lkml.kernel.org/r/20240814101119.4070-1-konishi.ryusuke@gmail.com
Fixes: a694291a6211 ("nilfs2: separate wait function from nilfs_segctor_write")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In an error injection test of a routine for mount-time recovery, KASAN
found a use-after-free bug.
It turned out that if data recovery was performed using partial logs
created by dsync writes, but an error occurred before starting the log
writer to create a recovered checkpoint, the inodes whose data had been
recovered were left in the ns_dirty_files list of the nilfs object and
were not freed.
Fix this issue by cleaning up inodes that have read the recovery data if
the recovery routine fails midway before the log writer starts.
Link: https://lkml.kernel.org/r/20240810065242.3701-1-konishi.ryusuke@gmail.com
Fixes: 0f3e1c7f23f8 ("nilfs2: recovery functions")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The superblock buffers of nilfs2 can not only be overwritten at runtime
for modifications/repairs, but they are also regularly swapped, replaced
during resizing, and even abandoned when degrading to one side due to
backing device issues. So, accessing them requires mutual exclusion using
the reader/writer semaphore "nilfs->ns_sem".
Some sysfs attribute show methods read this superblock buffer without the
necessary mutual exclusion, which can cause problems with pointer
dereferencing and memory access, so fix it.
Link: https://lkml.kernel.org/r/20240811100320.9913-1-konishi.ryusuke@gmail.com
Fixes: da7141fb78db ("nilfs2: add /sys/fs/nilfs2/<device> group")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Syzbot reported that a buffer state inconsistency was detected in
nilfs_btnode_create_block(), triggering a kernel bug.
It is not appropriate to treat this inconsistency as a bug; it can occur
if the argument block address (the buffer index of the newly created
block) is a virtual block number and has been reallocated due to
corruption of the bitmap used to manage its allocation state.
So, modify nilfs_btnode_create_block() and its callers to treat it as a
possible filesystem error, rather than triggering a kernel bug.
Link: https://lkml.kernel.org/r/20240725052007.4562-1-konishi.ryusuke@gmail.com
Fixes: a60be987d45d ("nilfs2: B-tree node cache")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+89cc4f2324ed37988b60@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=89cc4f2324ed37988b60
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
- In the series "treewide: Refactor heap related implementation",
Kuan-Wei Chiu has significantly reworked the min_heap library code
and has taught bcachefs to use the new more generic implementation.
- Yury Norov's series "Cleanup cpumask.h inclusion in core headers"
reworks the cpumask and nodemask headers to make things generally
more rational.
- Kuan-Wei Chiu has sent along some maintenance work against our
sorting library code in the series "lib/sort: Optimizations and
cleanups".
- More library maintainance work from Christophe Jaillet in the series
"Remove usage of the deprecated ida_simple_xx() API".
- Ryusuke Konishi continues with the nilfs2 fixes and clanups in the
series "nilfs2: eliminate the call to inode_attach_wb()".
- Kuan-Ying Lee has some fixes to the gdb scripts in the series "Fix
GDB command error".
- Plus the usual shower of singleton patches all over the place. Please
see the relevant changelogs for details.
* tag 'mm-nonmm-stable-2024-07-21-15-07' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (98 commits)
ia64: scrub ia64 from poison.h
watchdog/perf: properly initialize the turbo mode timestamp and rearm counter
tsacct: replace strncpy() with strscpy()
lib/bch.c: use swap() to improve code
test_bpf: convert comma to semicolon
init/modpost: conditionally check section mismatch to __meminit*
init: remove unused __MEMINIT* macros
nilfs2: Constify struct kobj_type
nilfs2: avoid undefined behavior in nilfs_cnt32_ge macro
math: rational: add missing MODULE_DESCRIPTION() macro
lib/zlib: add missing MODULE_DESCRIPTION() macro
fs: ufs: add MODULE_DESCRIPTION()
lib/rbtree.c: fix the example typo
ocfs2: add bounds checking to ocfs2_check_dir_entry()
fs: add kernel-doc comments to ocfs2_prepare_orphan_dir()
coredump: simplify zap_process()
selftests/fpu: add missing MODULE_DESCRIPTION() macro
compiler.h: simplify data_race() macro
build-id: require program headers to be right after ELF header
resource: add missing MODULE_DESCRIPTION()
...
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'struct kobj_type' is not modified in this driver. It is only used with
kobject_init_and_add() which takes a "const struct kobj_type *" parameter.
Constifying this structure moves some data to a read-only section, so
increase overall security.
On a x86_64, with allmodconfig:
Before:
======
text data bss dec hex filename
22403 4184 24 26611 67f3 fs/nilfs2/sysfs.o
After:
=====
text data bss dec hex filename
22723 3928 24 26675 6833 fs/nilfs2/sysfs.o
Link: https://lkml.kernel.org/r/20240708143242.3296-1-konishi.ryusuke@gmail.com
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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crashes from deferred split racing folio migration", needed by "mm:
migrate: split folio_migrate_mapping()".
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According to the C standard 3.4.3p3, the result of signed integer overflow
is undefined. The macro nilfs_cnt32_ge(), which compares two sequence
numbers, uses signed integer subtraction that can overflow, and therefore
the result of the calculation may differ from what is expected due to
undefined behavior in different environments.
Similar to an earlier change to the jiffies-related comparison macros in
commit 5a581b367b5d ("jiffies: Avoid undefined behavior from signed
overflow"), avoid this potential issue by changing the definition of the
macro to perform the subtraction as unsigned integers, then cast the
result to a signed integer for comparison.
Link: https://lkml.kernel.org/r/20130727225828.GA11864@linux.vnet.ibm.com
Link: https://lkml.kernel.org/r/20240702183512.6390-1-konishi.ryusuke@gmail.com
Fixes: 9ff05123e3bf ("nilfs2: segment constructor")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Syzbot reported that in rename directory operation on broken directory on
nilfs2, __block_write_begin_int() called to prepare block write may fail
BUG_ON check for access exceeding the folio/page size.
This is because nilfs_dotdot(), which gets parent directory reference
entry ("..") of the directory to be moved or renamed, does not check
consistency enough, and may return location exceeding folio/page size for
broken directories.
Fix this issue by checking required directory entries ("." and "..") in
the first chunk of the directory in nilfs_dotdot().
Link: https://lkml.kernel.org/r/20240628165107.9006-1-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+d3abed1ad3d367fa2627@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=d3abed1ad3d367fa2627
Fixes: 2ba466d74ed7 ("nilfs2: directory entry operations")
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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If the bitmap block that manages the inode allocation status is corrupted,
nilfs_ifile_create_inode() may allocate a new inode from the reserved
inode area where it should not be allocated.
Previous fix commit d325dc6eb763 ("nilfs2: fix use-after-free bug of
struct nilfs_root"), fixed the problem that reserved inodes with inode
numbers less than NILFS_USER_INO (=11) were incorrectly reallocated due to
bitmap corruption, but since the start number of non-reserved inodes is
read from the super block and may change, in which case inode allocation
may occur from the extended reserved inode area.
If that happens, access to that inode will cause an IO error, causing the
file system to degrade to an error state.
Fix this potential issue by adding a wraparound option to the common
metadata object allocation routine and by modifying
nilfs_ifile_create_inode() to disable the option so that it only allocates
inodes with inode numbers greater than or equal to the inode number read
in "nilfs->ns_first_ino", regardless of the bitmap status of reserved
inodes.
Link: https://lkml.kernel.org/r/20240623051135.4180-4-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Syzbot reported that mounting and unmounting a specific pattern of
corrupted nilfs2 filesystem images causes a use-after-free of metadata
file inodes, which triggers a kernel bug in lru_add_fn().
As Jan Kara pointed out, this is because the link count of a metadata file
gets corrupted to 0, and nilfs_evict_inode(), which is called from iput(),
tries to delete that inode (ifile inode in this case).
The inconsistency occurs because directories containing the inode numbers
of these metadata files that should not be visible in the namespace are
read without checking.
Fix this issue by treating the inode numbers of these internal files as
errors in the sanity check helper when reading directory folios/pages.
Also thanks to Hillf Danton and Matthew Wilcox for their initial mm-layer
analysis.
Link: https://lkml.kernel.org/r/20240623051135.4180-3-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+d79afb004be235636ee8@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=d79afb004be235636ee8
Reported-by: Jan Kara <jack@suse.cz>
Closes: https://lkml.kernel.org/r/20240617075758.wewhukbrjod5fp5o@quack3
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "nilfs2: fix potential issues related to reserved inodes".
This series fixes one use-after-free issue reported by syzbot, caused by
nilfs2's internal inode being exposed in the namespace on a corrupted
filesystem, and a couple of flaws that cause problems if the starting
number of non-reserved inodes written in the on-disk super block is
intentionally (or corruptly) changed from its default value.
This patch (of 3):
In the current implementation of nilfs2, "nilfs->ns_first_ino", which
gives the first non-reserved inode number, is read from the superblock,
but its lower limit is not checked.
As a result, if a number that overlaps with the inode number range of
reserved inodes such as the root directory or metadata files is set in the
super block parameter, the inode number test macros (NILFS_MDT_INODE and
NILFS_VALID_INODE) will not function properly.
In addition, these test macros use left bit-shift calculations using with
the inode number as the shift count via the BIT macro, but the result of a
shift calculation that exceeds the bit width of an integer is undefined in
the C specification, so if "ns_first_ino" is set to a large value other
than the default value NILFS_USER_INO (=11), the macros may potentially
malfunction depending on the environment.
Fix these issues by checking the lower bound of "nilfs->ns_first_ino" and
by preventing bit shifts equal to or greater than the NILFS_USER_INO
constant in the inode number test macros.
Also, change the type of "ns_first_ino" from signed integer to unsigned
integer to avoid the need for type casting in comparisons such as the
lower bound check introduced this time.
Link: https://lkml.kernel.org/r/20240623051135.4180-1-konishi.ryusuke@gmail.com
Link: https://lkml.kernel.org/r/20240623051135.4180-2-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "mm/swap: clean up and optimize swap cache index", v6.
Currently we use one swap_address_space for every 64M chunk to reduce lock
contention, this is like having a set of smaller files inside a swap
device. But when doing swap cache look up or insert, we are still using
the offset of the whole large swap device. This is OK for correctness, as
the offset (key) is unique.
But Xarray is specially optimized for small indexes, it creates the redix
tree levels lazily to be just enough to fit the largest key stored in one
Xarray. So we are wasting tree nodes unnecessarily.
For 64M chunk it should only take at most 3 level to contain everything.
But if we are using the offset from the whole swap device, the offset
(key) value will be way beyond 64M, and so will the tree level.
Optimize this by reduce the swap cache search space into 64M scope.
Test with `time memhog 128G` inside a 8G memcg using 128G swap (ramdisk
with SWP_SYNCHRONOUS_IO dropped, tested 3 times, results are stable. The
test result is similar but the improvement is smaller if
SWP_SYNCHRONOUS_IO is enabled, as swap out path can never skip swap
cache):
Before:
6.07user 250.74system 4:17.26elapsed 99%CPU (0avgtext+0avgdata 8373376maxresident)k
0inputs+0outputs (55major+33555018minor)pagefaults 0swaps
After (+1.8% faster):
6.08user 246.09system 4:12.58elapsed 99%CPU (0avgtext+0avgdata 8373248maxresident)k
0inputs+0outputs (54major+33555027minor)pagefaults 0swaps
Similar result with MySQL and sysbench using swap:
Before:
94055.61 qps
After (+0.8% faster):
94834.91 qps
There is alse a very slight drop of radix tree node slab usage:
Before: 303952K
After: 302224K
For this series:
There are multiple places that expect mixed type of pages (page cache or
swap cache), eg. migration, huge memory split; There are four helpers
for that:
- page_index
- page_file_offset
- folio_index
- folio_file_pos
To keep the code clean and compatible, this series first cleaned up usage
of them.
page_file_offset and folio_file_pos are historical helpes that can be
simply dropped after clean up. And page_index can be all converted to
folio_index or folio->index.
Then introduce two new helpers swap_cache_index and swap_dev_pos for swap.
Replace swp_offset with swap_cache_index when used to retrieve folio from
swap cache, and use swap_dev_pos when needed to retrieve the device
position of a swap entry. This way, swap_cache_index can return the
optimized value with no compatibility issue.
The result is better performance and reduced LOC.
Idealy, in the future, we may want to reduce SWAP_ADDRESS_SPACE_SHIFT from
14 to 12: Default Xarray chunk offset is 6, so we have 3 level trees
instead of 2 level trees just for 2 extra bits. But swap cache is based
on address_space struct, with 4 times more metadata sparsely distributed
in memory it waste more cacheline, the performance gain from this series
is almost canceled according to my test. So first, just have a cleaner
seperation of offsets and smaller search space.
This patch (of 10):
page_index is only for mixed usage of page cache and swap cache, for pure
page cache usage, the caller can just use page->index instead.
It can't be a swap cache page here (being part of buffer head), so just
drop it. And while we are at it, optimize the code by retrieving the
offset of the buffer head within the folio directly using bh_offset, and
get rid of the loop and usage of page helpers.
Link: https://lkml.kernel.org/r/20240521175854.96038-1-ryncsn@gmail.com
Link: https://lkml.kernel.org/r/20240521175854.96038-3-ryncsn@gmail.com
Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Kairui Song <kasong@tencent.com>
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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If the bitmap block that manages the inode allocation status is corrupted,
nilfs_ifile_create_inode() may allocate a new inode from the reserved
inode area where it should not be allocated.
Previous fix commit d325dc6eb763 ("nilfs2: fix use-after-free bug of
struct nilfs_root"), fixed the problem that reserved inodes with inode
numbers less than NILFS_USER_INO (=11) were incorrectly reallocated due to
bitmap corruption, but since the start number of non-reserved inodes is
read from the super block and may change, in which case inode allocation
may occur from the extended reserved inode area.
If that happens, access to that inode will cause an IO error, causing the
file system to degrade to an error state.
Fix this potential issue by adding a wraparound option to the common
metadata object allocation routine and by modifying
nilfs_ifile_create_inode() to disable the option so that it only allocates
inodes with inode numbers greater than or equal to the inode number read
in "nilfs->ns_first_ino", regardless of the bitmap status of reserved
inodes.
Link: https://lkml.kernel.org/r/20240623051135.4180-4-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Syzbot reported that mounting and unmounting a specific pattern of
corrupted nilfs2 filesystem images causes a use-after-free of metadata
file inodes, which triggers a kernel bug in lru_add_fn().
As Jan Kara pointed out, this is because the link count of a metadata file
gets corrupted to 0, and nilfs_evict_inode(), which is called from iput(),
tries to delete that inode (ifile inode in this case).
The inconsistency occurs because directories containing the inode numbers
of these metadata files that should not be visible in the namespace are
read without checking.
Fix this issue by treating the inode numbers of these internal files as
errors in the sanity check helper when reading directory folios/pages.
Also thanks to Hillf Danton and Matthew Wilcox for their initial mm-layer
analysis.
Link: https://lkml.kernel.org/r/20240623051135.4180-3-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+d79afb004be235636ee8@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=d79afb004be235636ee8
Reported-by: Jan Kara <jack@suse.cz>
Closes: https://lkml.kernel.org/r/20240617075758.wewhukbrjod5fp5o@quack3
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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Patch series "nilfs2: fix potential issues related to reserved inodes".
This series fixes one use-after-free issue reported by syzbot, caused by
nilfs2's internal inode being exposed in the namespace on a corrupted
filesystem, and a couple of flaws that cause problems if the starting
number of non-reserved inodes written in the on-disk super block is
intentionally (or corruptly) changed from its default value.
This patch (of 3):
In the current implementation of nilfs2, "nilfs->ns_first_ino", which
gives the first non-reserved inode number, is read from the superblock,
but its lower limit is not checked.
As a result, if a number that overlaps with the inode number range of
reserved inodes such as the root directory or metadata files is set in the
super block parameter, the inode number test macros (NILFS_MDT_INODE and
NILFS_VALID_INODE) will not function properly.
In addition, these test macros use left bit-shift calculations using with
the inode number as the shift count via the BIT macro, but the result of a
shift calculation that exceeds the bit width of an integer is undefined in
the C specification, so if "ns_first_ino" is set to a large value other
than the default value NILFS_USER_INO (=11), the macros may potentially
malfunction depending on the environment.
Fix these issues by checking the lower bound of "nilfs->ns_first_ino" and
by preventing bit shifts equal to or greater than the NILFS_USER_INO
constant in the inode number test macros.
Also, change the type of "ns_first_ino" from signed integer to unsigned
integer to avoid the need for type casting in comparisons such as the
lower bound check introduced this time.
Link: https://lkml.kernel.org/r/20240623051135.4180-1-konishi.ryusuke@gmail.com
Link: https://lkml.kernel.org/r/20240623051135.4180-2-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Call mark_buffer_dirty() for segment summary and super root block buffers
on the backing device's page cache, thereby indirectly calling
inode_attach_wb().
Then remove the no longer needed call to inode_attach_wb() in
nilfs_attach_log_writer(), resolving the concern about its layer-violating
use.
Link: https://lkml.kernel.org/r/20240610160029.7673-3-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "nilfs2: eliminate the call to inode_attach_wb()".
This series eliminates the inode_attach_wb() call from nilfs2, which was
introduced as a workaround for a kernel bug but is suspected of layer
violation (in fact, it is undesirable since it exposes a reference to the
backing device).
Removal of the inode_attach_wb() call is done by simply using
mark_buffer_dirty() on the backing device's buffers. To use it safely,
this series will prepare it in patch 1/2, and perform the replacement
itself in patch 2/2.
This patch (of 2):
In preparation for inode_attach_wb(), which is currently called when
attaching the log writer, to be done via mark_buffer_dirty(), change the
order of preparation for log writing.
Specifically, the function call that adds checksums to segment summary and
super root blocks, which correspond to the log header and trailer, is made
before starting writeback of folios containing those blocks.
The current steps are as follows:
1. Put the folios of segment summary blocks in writeback state.
2. Put the folios of data blocks, metadata file blocks, and btree node
blocks (collectively called payload blocks) into writeback state.
3. Put the super root block folio in writeback state.
4. Add checksums.
Change these as follows:
1. Put the folios of payload blocks in writeback state.
2. Add checksums.
3. Put the folios of segment summary blocks in writeback state.
4. Put the super root block folio in writeback state.
In this order, the contents of segment summaries and super root block
that directly use buffer/folio of the backing device can be determined
including the addition of checksums, before preparing to write.
Step (1), which puts the payload block folios in writeback state, is
performed first because if there are memory-mapped data blocks, a valid
checksum can only be calculated after step (1).
Link: https://lkml.kernel.org/r/20240610160029.7673-2-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The error handling in nilfs_empty_dir() when a directory folio/page read
fails is incorrect, as in the old ext2 implementation, and if the
folio/page cannot be read or nilfs_check_folio() fails, it will falsely
determine the directory as empty and corrupt the file system.
In addition, since nilfs_empty_dir() does not immediately return on a
failed folio/page read, but continues to loop, this can cause a long loop
with I/O if i_size of the directory's inode is also corrupted, causing the
log writer thread to wait and hang, as reported by syzbot.
Fix these issues by making nilfs_empty_dir() immediately return a false
value (0) if it fails to get a directory folio/page.
Link: https://lkml.kernel.org/r/20240604134255.7165-1-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+c8166c541d3971bf6c87@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c8166c541d3971bf6c87
Fixes: 2ba466d74ed7 ("nilfs2: directory entry operations")
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Destructive writes to a block device on which nilfs2 is mounted can cause
a kernel bug in the folio/page writeback start routine or writeback end
routine (__folio_start_writeback in the log below):
kernel BUG at mm/page-writeback.c:3070!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
...
RIP: 0010:__folio_start_writeback+0xbaa/0x10e0
Code: 25 ff 0f 00 00 0f 84 18 01 00 00 e8 40 ca c6 ff e9 17 f6 ff ff
e8 36 ca c6 ff 4c 89 f7 48 c7 c6 80 c0 12 84 e8 e7 b3 0f 00 90 <0f>
0b e8 1f ca c6 ff 4c 89 f7 48 c7 c6 a0 c6 12 84 e8 d0 b3 0f 00
...
Call Trace:
<TASK>
nilfs_segctor_do_construct+0x4654/0x69d0 [nilfs2]
nilfs_segctor_construct+0x181/0x6b0 [nilfs2]
nilfs_segctor_thread+0x548/0x11c0 [nilfs2]
kthread+0x2f0/0x390
ret_from_fork+0x4b/0x80
ret_from_fork_asm+0x1a/0x30
</TASK>
This is because when the log writer starts a writeback for segment summary
blocks or a super root block that use the backing device's page cache, it
does not wait for the ongoing folio/page writeback, resulting in an
inconsistent writeback state.
Fix this issue by waiting for ongoing writebacks when putting
folios/pages on the backing device into writeback state.
Link: https://lkml.kernel.org/r/20240530141556.4411-1-konishi.ryusuke@gmail.com
Fixes: 9ff05123e3bf ("nilfs2: segment constructor")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Syzbot has reported a potential hang in nilfs_detach_log_writer() called
during nilfs2 unmount.
Analysis revealed that this is because nilfs_segctor_sync(), which
synchronizes with the log writer thread, can be called after
nilfs_segctor_destroy() terminates that thread, as shown in the call trace
below:
nilfs_detach_log_writer
nilfs_segctor_destroy
nilfs_segctor_kill_thread --> Shut down log writer thread
flush_work
nilfs_iput_work_func
nilfs_dispose_list
iput
nilfs_evict_inode
nilfs_transaction_commit
nilfs_construct_segment (if inode needs sync)
nilfs_segctor_sync --> Attempt to synchronize with
log writer thread
*** DEADLOCK ***
Fix this issue by changing nilfs_segctor_sync() so that the log writer
thread returns normally without synchronizing after it terminates, and by
forcing tasks that are already waiting to complete once after the thread
terminates.
The skipped inode metadata flushout will then be processed together in the
subsequent cleanup work in nilfs_segctor_destroy().
Link: https://lkml.kernel.org/r/20240520132621.4054-4-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+e3973c409251e136fdd0@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=e3973c409251e136fdd0
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Cc: "Bai, Shuangpeng" <sjb7183@psu.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
A potential and reproducible race issue has been identified where
nilfs_segctor_sync() would block even after the log writer thread writes a
checkpoint, unless there is an interrupt or other trigger to resume log
writing.
This turned out to be because, depending on the execution timing of the
log writer thread running in parallel, the log writer thread may skip
responding to nilfs_segctor_sync(), which causes a call to schedule()
waiting for completion within nilfs_segctor_sync() to lose the opportunity
to wake up.
The reason why waking up the task waiting in nilfs_segctor_sync() may be
skipped is that updating the request generation issued using a shared
sequence counter and adding an wait queue entry to the request wait queue
to the log writer, are not done atomically. There is a possibility that
log writing and request completion notification by nilfs_segctor_wakeup()
may occur between the two operations, and in that case, the wait queue
entry is not yet visible to nilfs_segctor_wakeup() and the wake-up of
nilfs_segctor_sync() will be carried over until the next request occurs.
Fix this issue by performing these two operations simultaneously within
the lock section of sc_state_lock. Also, following the memory barrier
guidelines for event waiting loops, move the call to set_current_state()
in the same location into the event waiting loop to ensure that a memory
barrier is inserted just before the event condition determination.
Link: https://lkml.kernel.org/r/20240520132621.4054-3-konishi.ryusuke@gmail.com
Fixes: 9ff05123e3bf ("nilfs2: segment constructor")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Cc: "Bai, Shuangpeng" <sjb7183@psu.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "nilfs2: fix log writer related issues".
This bug fix series covers three nilfs2 log writer-related issues,
including a timer use-after-free issue and potential deadlock issue on
unmount, and a potential freeze issue in event synchronization found
during their analysis. Details are described in each commit log.
This patch (of 3):
A use-after-free issue has been reported regarding the timer sc_timer on
the nilfs_sc_info structure.
The problem is that even though it is used to wake up a sleeping log
writer thread, sc_timer is not shut down until the nilfs_sc_info structure
is about to be freed, and is used regardless of the thread's lifetime.
Fix this issue by limiting the use of sc_timer only while the log writer
thread is alive.
Link: https://lkml.kernel.org/r/20240520132621.4054-1-konishi.ryusuke@gmail.com
Link: https://lkml.kernel.org/r/20240520132621.4054-2-konishi.ryusuke@gmail.com
Fixes: fdce895ea5dd ("nilfs2: change sc_timer from a pointer to an embedded one in struct nilfs_sc_info")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: "Bai, Shuangpeng" <sjb7183@psu.edu>
Closes: https://groups.google.com/g/syzkaller/c/MK_LYqtt8ko/m/8rgdWeseAwAJ
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull more non-mm updates from Andrew Morton:
- A series ("kbuild: enable more warnings by default") from Arnd
Bergmann which enables a number of additional build-time warnings. We
fixed all the fallout which we could find, there may still be a few
stragglers.
- Samuel Holland has developed the series "Unified cross-architecture
kernel-mode FPU API". This does a lot of consolidation of
per-architecture kernel-mode FPU usage and enables the use of newer
AMD GPUs on RISC-V.
- Tao Su has fixed some selftests build warnings in the series
"Selftests: Fix compilation warnings due to missing _GNU_SOURCE
definition".
- This pull also includes a nilfs2 fixup from Ryusuke Konishi.
* tag 'mm-nonmm-stable-2024-05-22-17-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (23 commits)
nilfs2: make block erasure safe in nilfs_finish_roll_forward()
selftests/harness: use 1024 in place of LINE_MAX
Revert "selftests/harness: remove use of LINE_MAX"
selftests/fpu: allow building on other architectures
selftests/fpu: move FP code to a separate translation unit
drm/amd/display: use ARCH_HAS_KERNEL_FPU_SUPPORT
drm/amd/display: only use hard-float, not altivec on powerpc
riscv: add support for kernel-mode FPU
x86: implement ARCH_HAS_KERNEL_FPU_SUPPORT
powerpc: implement ARCH_HAS_KERNEL_FPU_SUPPORT
LoongArch: implement ARCH_HAS_KERNEL_FPU_SUPPORT
lib/raid6: use CC_FLAGS_FPU for NEON CFLAGS
arm64: crypto: use CC_FLAGS_FPU for NEON CFLAGS
arm64: implement ARCH_HAS_KERNEL_FPU_SUPPORT
ARM: crypto: use CC_FLAGS_FPU for NEON CFLAGS
ARM: implement ARCH_HAS_KERNEL_FPU_SUPPORT
arch: add ARCH_HAS_KERNEL_FPU_SUPPORT
x86/fpu: fix asm/fpu/types.h include guard
kbuild: enable -Wcast-function-type-strict unconditionally
kbuild: enable -Wformat-truncation on clang
...
|
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull bdev bd_inode updates from Al Viro:
"Replacement |
