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Merge tag 'block-5.13-2021-06-12' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
"A few fixes that should go into 5.13:
- Fix a regression deadlock introduced in this release between open
and remove of a bdev (Christoph)
- Fix an async_xor md regression in this release (Xiao)
- Fix bcache oversized read issue (Coly)"
* tag 'block-5.13-2021-06-12' of git://git.kernel.dk/linux-block:
block: loop: fix deadlock between open and remove
async_xor: check src_offs is not NULL before updating it
bcache: avoid oversized read request in cache missing code path
bcache: remove bcache device self-defined readahead
In the cache missing code path of cached device, if a proper location
from the internal B+ tree is matched for a cache miss range, function
cached_dev_cache_miss() will be called in cache_lookup_fn() in the
following code block,
[code block 1]
526 unsigned int sectors = KEY_INODE(k) == s->iop.inode
527 ? min_t(uint64_t, INT_MAX,
528 KEY_START(k) - bio->bi_iter.bi_sector)
529 : INT_MAX;
530 int ret = s->d->cache_miss(b, s, bio, sectors);
Here s->d->cache_miss() is the call backfunction pointer initialized as
cached_dev_cache_miss(), the last parameter 'sectors' is an important
hint to calculate the size of read request to backing device of the
missing cache data.
Current calculation in above code block may generate oversized value of
'sectors', which consequently may trigger 2 different potential kernel
panics by BUG() or BUG_ON() as listed below,
1) BUG_ON() inside bch_btree_insert_key(),
[code block 2]
886 BUG_ON(b->ops->is_extents && !KEY_SIZE(k));
2) BUG() inside biovec_slab(),
[code block 3]
51 default:
52 BUG();
53 return NULL;
All the above panics are original from cached_dev_cache_miss() by the
oversized parameter 'sectors'.
Inside cached_dev_cache_miss(), parameter 'sectors' is used to calculate
the size of data read from backing device for the cache missing. This
size is stored in s->insert_bio_sectors by the following lines of code,
[code block 4]
909 s->insert_bio_sectors = min(sectors, bio_sectors(bio) + reada);
Then the actual key inserting to the internal B+ tree is generated and
stored in s->iop.replace_key by the following lines of code,
[code block 5]
911 s->iop.replace_key = KEY(s->iop.inode,
912 bio->bi_iter.bi_sector + s->insert_bio_sectors,
913 s->insert_bio_sectors);
The oversized parameter 'sectors' may trigger panic 1) by BUG_ON() from
the above code block.
And the bio sending to backing device for the missing data is allocated
with hint from s->insert_bio_sectors by the following lines of code,
[code block 6]
926 cache_bio = bio_alloc_bioset(GFP_NOWAIT,
927 DIV_ROUND_UP(s->insert_bio_sectors, PAGE_SECTORS),
928 &dc->disk.bio_split);
The oversized parameter 'sectors' may trigger panic 2) by BUG() from the
agove code block.
Now let me explain how the panics happen with the oversized 'sectors'.
In code block 5, replace_key is generated by macro KEY(). From the
definition of macro KEY(),
[code block 7]
71 #define KEY(inode, offset, size) \
72 ((struct bkey) { \
73 .high = (1ULL << 63) | ((__u64) (size) << 20) | (inode), \
74 .low = (offset) \
75 })
Here 'size' is 16bits width embedded in 64bits member 'high' of struct
bkey. But in code block 1, if "KEY_START(k) - bio->bi_iter.bi_sector" is
very probably to be larger than (1<<16) - 1, which makes the bkey size
calculation in code block 5 is overflowed. In one bug report the value
of parameter 'sectors' is 131072 (= 1 << 17), the overflowed 'sectors'
results the overflowed s->insert_bio_sectors in code block 4, then makes
size field of s->iop.replace_key to be 0 in code block 5. Then the 0-
sized s->iop.replace_key is inserted into the internal B+ tree as cache
missing check key (a special key to detect and avoid a racing between
normal write request and cache missing read request) as,
[code block 8]
915 ret = bch_btree_insert_check_key(b, &s->op, &s->iop.replace_key);
Then the 0-sized s->iop.replace_key as 3rd parameter triggers the bkey
size check BUG_ON() in code block 2, and causes the kernel panic 1).
Another kernel panic is from code block 6, is by the bvecs number
oversized value s->insert_bio_sectors from code block 4,
min(sectors, bio_sectors(bio) + reada)
There are two possibility for oversized reresult,
- bio_sectors(bio) is valid, but bio_sectors(bio) + reada is oversized.
- sectors < bio_sectors(bio) + reada, but sectors is oversized.
From a bug report the result of "DIV_ROUND_UP(s->insert_bio_sectors,
PAGE_SECTORS)" from code block 6 can be 344, 282, 946, 342 and many
other values which larther than BIO_MAX_VECS (a.k.a 256). When calling
bio_alloc_bioset() with such larger-than-256 value as the 2nd parameter,
this value will eventually be sent to biovec_slab() as parameter
'nr_vecs' in following code path,
bio_alloc_bioset() ==> bvec_alloc() ==> biovec_slab()
Because parameter 'nr_vecs' is larger-than-256 value, the panic by BUG()
in code block 3 is triggered inside biovec_slab().
From the above analysis, we know that the 4th parameter 'sector' sent
into cached_dev_cache_miss() may cause overflow in code block 5 and 6,
and finally cause kernel panic in code block 2 and 3. And if result of
bio_sectors(bio) + reada exceeds valid bvecs number, it may also trigger
kernel panic in code block 3 from code block 6.
Now the almost-useless readahead size for cache missing request back to
backing device is removed, this patch can fix the oversized issue with
more simpler method.
- add a local variable size_limit, set it by the minimum value from
the max bkey size and max bio bvecs number.
- set s->insert_bio_sectors by the minimum value from size_limit,
sectors, and the sectors size of bio.
- replace sectors by s->insert_bio_sectors to do bio_next_split.
By the above method with size_limit, s->insert_bio_sectors will never
result oversized replace_key size or bio bvecs number. And split bio
'miss' from bio_next_split() will always match the size of 'cache_bio',
that is the current maximum bio size we can sent to backing device for
fetching the cache missing data.
Current problmatic code can be partially found since Linux v3.13-rc1,
therefore all maintained stable kernels should try to apply this fix.
Reported-by: Alexander Ullrich <ealex1979@gmail.com>
Reported-by: Diego Ercolani <diego.ercolani@gmail.com>
Reported-by: Jan Szubiak <jan.szubiak@linuxpolska.pl>
Reported-by: Marco Rebhan <me@dblsaiko.net>
Reported-by: Matthias Ferdinand <bcache@mfedv.net>
Reported-by: Victor Westerhuis <victor@westerhu.is>
Reported-by: Vojtech Pavlik <vojtech@suse.cz>
Reported-and-tested-by: Rolf Fokkens <rolf@rolffokkens.nl>
Reported-and-tested-by: Thorsten Knabe <linux@thorsten-knabe.de>
Signed-off-by: Coly Li <colyli@suse.de>
Cc: stable@vger.kernel.org
Cc: Christoph Hellwig <hch@lst.de>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Nix <nix@esperi.org.uk>
Cc: Takashi Iwai <tiwai@suse.com>
Link: https://lore.kernel.org/r/20210607125052.21277-3-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For read cache missing, bcache defines a readahead size for the read I/O
request to the backing device for the missing data. This readahead size
is initialized to 0, and almost no one uses it to avoid unnecessary read
amplifying onto backing device and write amplifying onto cache device.
Considering upper layer file system code has readahead logic allready
and works fine with readahead_cache_policy sysfile interface, we don't
have to keep bcache self-defined readahead anymore.
This patch removes the bcache self-defined readahead for cache missing
request for backing device, and the readahead sysfs file interfaces are
removed as well.
This is the preparation for next patch to fix potential kernel panic due
to oversized request in a simpler method.
Reported-by: Alexander Ullrich <ealex1979@gmail.com>
Reported-by: Diego Ercolani <diego.ercolani@gmail.com>
Reported-by: Jan Szubiak <jan.szubiak@linuxpolska.pl>
Reported-by: Marco Rebhan <me@dblsaiko.net>
Reported-by: Matthias Ferdinand <bcache@mfedv.net>
Reported-by: Victor Westerhuis <victor@westerhu.is>
Reported-by: Vojtech Pavlik <vojtech@suse.cz>
Reported-and-tested-by: Rolf Fokkens <rolf@rolffokkens.nl>
Reported-and-tested-by: Thorsten Knabe <linux@thorsten-knabe.de>
Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Nix <nix@esperi.org.uk>
Cc: Takashi Iwai <tiwai@suse.com>
Link: https://lore.kernel.org/r/20210607125052.21277-2-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now that the original bdev is stored in the bio this assert is incorrect
and will trigger for any partitioned raid5 device.
Reported-by: Florian Dazinger <spam02@dazinger.net>
Tested-by: Florian Dazinger <spam02@dazinger.net>
Cc: stable@vger.kernel.org # 5.12
Fixes: 309dca309f ("block: store a block_device pointer in struct bio"),
Reviewed-by: Guoqing Jiang <jiangguoqing@kylinos.cn>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>
If an origin target has no snapshots, o->split_boundary is set to 0.
This causes BUG_ON(sectors <= 0) in block/bio.c:bio_split().
Fix this by initializing chunk_size, and in turn split_boundary, to
rounddown_pow_of_two(UINT_MAX) -- the largest power of two that fits
into "unsigned" type.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Commit 7ee06ddc40 ("dm snapshot: fix a
crash when an origin has no snapshots") introduced a regression in
snapshot merging - causing the lvm2 test lvcreate-cache-snapshot.sh
got stuck in an infinite loop.
Even though commit 7ee06ddc40 was marked
for stable@ the stable team was notified to _not_ backport it.
Fixes: 7ee06ddc40 ("dm snapshot: fix a crash when an origin has no snapshots")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
The third parameter of module_param() is permissions for the sysfs node
but it looks like it is being used as the initial value of the parameter
here. In fact, false here equates to omitting the file from sysfs and
does not affect the value of require_signatures.
Making the parameter writable is not simple because going from
false->true is fine but it should not be possible to remove the
requirement to verify a signature. But it can be useful to inspect the
value of this parameter from userspace, so change the permissions to
make a read-only file in sysfs.
Signed-off-by: John Keeping <john@metanate.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Use the types __le* instead of __u* to fix sparse warnings.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Revert the commit 7a5b96b478 ("dm integrity:
use discard support when recalculating").
There's a bug that when we write some data beyond the current recalculate
boundary, the checksum will be rewritten with the discard filler later.
And the data will no longer have integrity protection. There's no easy
fix for this case.
Also, another problematic case is if dm-integrity is used to detect
bitrot (random device errors, bit flips, etc); dm-integrity should
detect that even for unused sectors. With commit 7a5b96b478 it can
happen that such change is undetected (because discard filler is not a
valid checksum).
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
The following commands will crash the kernel:
modprobe brd rd_size=1048576
dmsetup create o --table "0 `blockdev --getsize /dev/ram0` snapshot-origin /dev/ram0"
dmsetup create s --table "0 `blockdev --getsize /dev/ram0` snapshot /dev/ram0 /dev/ram1 N 0"
The reason is that when we test for zero chunk size, we jump to the label
bad_read_metadata without setting the "r" variable. The function
snapshot_ctr destroys all the structures and then exits with "r == 0". The
kernel then crashes because it falsely believes that snapshot_ctr
succeeded.
In order to fix the bug, we set the variable "r" to -EINVAL.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
If an origin target has no snapshots, o->split_boundary is set to 0.
This causes BUG_ON(sectors <= 0) in block/bio.c:bio_split().
Fix this by initializing chunk_size, and in turn split_boundary, to
rounddown_pow_of_two(UINT_MAX) -- the largest power of two that fits
into "unsigned" type.
Reported-by: Michael Tokarev <mjt@tls.msk.ru>
Tested-by: Michael Tokarev <mjt@tls.msk.ru>
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
My UEK-derived config has 1030 files depending on pagemap.h before this
change. Afterwards, just 326 files need to be rebuilt when I touch
pagemap.h. I think blkdev.h is probably included too widely, but
untangling that dependency is harder and this solves my problem. x86
allmodconfig builds, but there may be implicit include problems on other
architectures.
Link: https://lkml.kernel.org/r/20210309195747.283796-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Dan Williams <dan.j.williams@intel.com> [nvdimm]
Acked-by: Jens Axboe <axboe@kernel.dk> [block]
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Coly Li <colyli@suse.de> [bcache]
Acked-by: Martin K. Petersen <martin.petersen@oracle.com> [scsi]
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Extend DM ioctl's DM_LIST_DEVICES_CMD handling to include UUID and
allow filtering based on name or UUID prefix.
- Various small fixes for typos, warnings, unused function, or
needlessly exported interfaces.
- Remove needless request_queue NULL pointer checks in DM thin and
cache targets.
- Remove unnecessary loop in DM core's __split_and_process_bio().
- Remove DM core's dm_vcalloc() and just use kvcalloc or
kvmalloc_array instead (depending whether zeroing is useful).
- Fix request-based DM's double free of blk_mq_tag_set in device
remove after table load fails.
- Improve DM persistent data performance on non-x86 by fixing packed
structs to have a stated alignment. Also remove needless extra work
from redundant calls to sm_disk_get_nr_free() and a paranoid BUG_ON()
that caused duplicate checksum calculation.
- Fix missing goto in DM integrity's bitmap_flush_interval error
handling.
- Add "reset_recalculate" feature flag to DM integrity.
- Improve DM integrity by leveraging discard support to avoid needless
re-writing of metadata and also use discard support to improve
hash recalculation.
- Fix race with DM raid target's reshape and MD raid4/5/6 resync that
resulted in inconsistant reshape state during table reloads.
- Update DM raid target to temove unnecessary discard limits for raid0
and raid10 now that MD has optimized discard handling for both raid
levels.
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Merge tag 'for-5.13/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper updates from Mike Snitzer:
- Improve scalability of DM's device hash by switching to rbtree
- Extend DM ioctl's DM_LIST_DEVICES_CMD handling to include UUID and
allow filtering based on name or UUID prefix.
- Various small fixes for typos, warnings, unused function, or
needlessly exported interfaces.
- Remove needless request_queue NULL pointer checks in DM thin and
cache targets.
- Remove unnecessary loop in DM core's __split_and_process_bio().
- Remove DM core's dm_vcalloc() and just use kvcalloc or kvmalloc_array
instead (depending whether zeroing is useful).
- Fix request-based DM's double free of blk_mq_tag_set in device remove
after table load fails.
- Improve DM persistent data performance on non-x86 by fixing packed
structs to have a stated alignment. Also remove needless extra work
from redundant calls to sm_disk_get_nr_free() and a paranoid BUG_ON()
that caused duplicate checksum calculation.
- Fix missing goto in DM integrity's bitmap_flush_interval error
handling.
- Add "reset_recalculate" feature flag to DM integrity.
- Improve DM integrity by leveraging discard support to avoid needless
re-writing of metadata and also use discard support to improve hash
recalculation.
- Fix race with DM raid target's reshape and MD raid4/5/6 resync that
resulted in inconsistant reshape state during table reloads.
- Update DM raid target to temove unnecessary discard limits for raid0
and raid10 now that MD has optimized discard handling for both raid
levels.
* tag 'for-5.13/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (26 commits)
dm raid: remove unnecessary discard limits for raid0 and raid10
dm rq: fix double free of blk_mq_tag_set in dev remove after table load fails
dm integrity: use discard support when recalculating
dm integrity: increase RECALC_SECTORS to improve recalculate speed
dm integrity: don't re-write metadata if discarding same blocks
dm raid: fix inconclusive reshape layout on fast raid4/5/6 table reload sequences
dm raid: fix fall-through warning in rs_check_takeover() for Clang
dm clone metadata: remove unused function
dm integrity: fix missing goto in bitmap_flush_interval error handling
dm: replace dm_vcalloc()
dm space map common: fix division bug in sm_ll_find_free_block()
dm persistent data: packed struct should have an aligned() attribute too
dm btree spine: remove paranoid node_check call in node_prep_for_write()
dm space map disk: remove redundant calls to sm_disk_get_nr_free()
dm integrity: add the "reset_recalculate" feature flag
dm persistent data: remove unused return from exit_shadow_spine()
dm cache: remove needless request_queue NULL pointer checks
dm thin: remove needless request_queue NULL pointer check
dm: unexport dm_{get,put}_table_device
dm ebs: fix a few typos
...
When loading a device-mapper table for a request-based mapped device,
and the allocation/initialization of the blk_mq_tag_set for the device
fails, a following device remove will cause a double free.
E.g. (dmesg):
device-mapper: core: Cannot initialize queue for request-based dm-mq mapped device
device-mapper: ioctl: unable to set up device queue for new table.
Unable to handle kernel pointer dereference in virtual kernel address space
Failing address: 0305e098835de000 TEID: 0305e098835de803
Fault in home space mode while using kernel ASCE.
AS:000000025efe0007 R3:0000000000000024
Oops: 0038 ilc:3 [#1] SMP
Modules linked in: ... lots of modules ...
Supported: Yes, External
CPU: 0 PID: 7348 Comm: multipathd Kdump: loaded Tainted: G W X 5.3.18-53-default #1 SLE15-SP3
Hardware name: IBM 8561 T01 7I2 (LPAR)
Krnl PSW : 0704e00180000000 000000025e368eca (kfree+0x42/0x330)
R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3
Krnl GPRS: 000000000000004a 000000025efe5230 c1773200d779968d 0000000000000000
000000025e520270 000000025e8d1b40 0000000000000003 00000007aae10000
000000025e5202a2 0000000000000001 c1773200d779968d 0305e098835de640
00000007a8170000 000003ff80138650 000000025e5202a2 000003e00396faa8
Krnl Code: 000000025e368eb8: c4180041e100 lgrl %r1,25eba50b8
000000025e368ebe: ecba06b93a55 risbg %r11,%r10,6,185,58
#000000025e368ec4: e3b010000008 ag %r11,0(%r1)
>000000025e368eca: e310b0080004 lg %r1,8(%r11)
000000025e368ed0: a7110001 tmll %r1,1
000000025e368ed4: a7740129 brc 7,25e369126
000000025e368ed8: e320b0080004 lg %r2,8(%r11)
000000025e368ede: b904001b lgr %r1,%r11
Call Trace:
[<000000025e368eca>] kfree+0x42/0x330
[<000000025e5202a2>] blk_mq_free_tag_set+0x72/0xb8
[<000003ff801316a8>] dm_mq_cleanup_mapped_device+0x38/0x50 [dm_mod]
[<000003ff80120082>] free_dev+0x52/0xd0 [dm_mod]
[<000003ff801233f0>] __dm_destroy+0x150/0x1d0 [dm_mod]
[<000003ff8012bb9a>] dev_remove+0x162/0x1c0 [dm_mod]
[<000003ff8012a988>] ctl_ioctl+0x198/0x478 [dm_mod]
[<000003ff8012ac8a>] dm_ctl_ioctl+0x22/0x38 [dm_mod]
[<000000025e3b11ee>] ksys_ioctl+0xbe/0xe0
[<000000025e3b127a>] __s390x_sys_ioctl+0x2a/0x40
[<000000025e8c15ac>] system_call+0xd8/0x2c8
Last Breaking-Event-Address:
[<000000025e52029c>] blk_mq_free_tag_set+0x6c/0xb8
Kernel panic - not syncing: Fatal exception: panic_on_oops
When allocation/initialization of the blk_mq_tag_set fails in
dm_mq_init_request_queue(), it is uninitialized/freed, but the pointer
is not reset to NULL; so when dev_remove() later gets into
dm_mq_cleanup_mapped_device() it sees the pointer and tries to
uninitialize and free it again.
Fix this by setting the pointer to NULL in dm_mq_init_request_queue()
error-handling. Also set it to NULL in dm_mq_cleanup_mapped_device().
Cc: <stable@vger.kernel.org> # 4.6+
Fixes: 1c357a1e86 ("dm: allocate blk_mq_tag_set rather than embed in mapped_device")
Signed-off-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
If we have discard support we don't have to recalculate hash - we can
just fill the metadata with the discard pattern.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Increase RECALC_SECTORS because it improves recalculate speed slightly
(from 390kiB/s to 410kiB/s).
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
If we discard already discarded blocks we do not need to write discard
pattern to the metadata, because it is already there.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
- Clean up list_sort prototypes (Sami Tolvanen)
- Introduce CONFIG_CFI_CLANG for arm64 (Sami Tolvanen)
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Merge tag 'cfi-v5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull CFI on arm64 support from Kees Cook:
"This builds on last cycle's LTO work, and allows the arm64 kernels to
be built with Clang's Control Flow Integrity feature. This feature has
happily lived in Android kernels for almost 3 years[1], so I'm excited
to have it ready for upstream.
The wide diffstat is mainly due to the treewide fixing of mismatched
list_sort prototypes. Other things in core kernel are to address
various CFI corner cases. The largest code portion is the CFI runtime
implementation itself (which will be shared by all architectures
implementing support for CFI). The arm64 pieces are Acked by arm64
maintainers rather than coming through the arm64 tree since carrying
this tree over there was going to be awkward.
CFI support for x86 is still under development, but is pretty close.
There are a handful of corner cases on x86 that need some improvements
to Clang and objtool, but otherwise works well.
Summary:
- Clean up list_sort prototypes (Sami Tolvanen)
- Introduce CONFIG_CFI_CLANG for arm64 (Sami Tolvanen)"
* tag 'cfi-v5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
arm64: allow CONFIG_CFI_CLANG to be selected
KVM: arm64: Disable CFI for nVHE
arm64: ftrace: use function_nocfi for ftrace_call
arm64: add __nocfi to __apply_alternatives
arm64: add __nocfi to functions that jump to a physical address
arm64: use function_nocfi with __pa_symbol
arm64: implement function_nocfi
psci: use function_nocfi for cpu_resume
lkdtm: use function_nocfi
treewide: Change list_sort to use const pointers
bpf: disable CFI in dispatcher functions
kallsyms: strip ThinLTO hashes from static functions
kthread: use WARN_ON_FUNCTION_MISMATCH
workqueue: use WARN_ON_FUNCTION_MISMATCH
module: ensure __cfi_check alignment
mm: add generic function_nocfi macro
cfi: add __cficanonical
add support for Clang CFI
This patch addresses a data corruption bug in raid1 arrays using bitmaps.
Without this fix, the bitmap bits for the failed I/O end up being cleared.
Since we are in the failure leg of raid1_end_write_request, the request
either needs to be retried (R1BIO_WriteError) or failed (R1BIO_Degraded).
Fixes: eeba6809d8 ("md/raid1: end bio when the device faulty")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Paul Clements <paul.clements@us.sios.com>
Signed-off-by: Song Liu <song@kernel.org>
If fast table reloads occur during an ongoing reshape of raid4/5/6
devices the target may race reading a superblock vs the the MD resync
thread; causing an inconclusive reshape state to be read in its
constructor.
lvm2 test lvconvert-raid-reshape-stripes-load-reload.sh can cause
BUG_ON() to trigger in md_run(), e.g.:
"kernel BUG at drivers/md/raid5.c:7567!".
Scenario triggering the bug:
1. the MD sync thread calls end_reshape() from raid5_sync_request()
when done reshaping. However end_reshape() _only_ updates the
reshape position to MaxSector keeping the changed layout
configuration though (i.e. any delta disks, chunk sector or RAID
algorithm changes). That inconclusive configuration is stored in
the superblock.
2. dm-raid constructs a mapping, loading named inconsistent superblock
as of step 1 before step 3 is able to finish resetting the reshape
state completely, and calls md_run() which leads to mentioned bug
in raid5.c.
3. the MD RAID personality's finish_reshape() is called; which resets
the reshape information on chunk sectors, delta disks, etc. This
explains why the bug is rarely seen on multi-core machines, as MD's
finish_reshape() superblock update races with the dm-raid
constructor's superblock load in step 2.
Fix identifies inconclusive superblock content in the dm-raid
constructor and resets it before calling md_run(), factoring out
identifying checks into rs_is_layout_change() to share in existing
rs_reshape_requested() and new rs_reset_inclonclusive_reshape(). Also
enhance a comment and remove an empty line.
Cc: stable@vger.kernel.org
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
In preparation to enable -Wimplicit-fallthrough for Clang, fix a warning
by explicitly adding a break statement instead of letting the code fall
through to the next case.
Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Use kvcalloc or kvmalloc_array instead (depending whether zeroing is
useful).
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This division bug meant the search for free metadata space could skip
the final allocation bitmap's worth of entries. Fix affects DM thinp,
cache and era targets.
Cc: stable@vger.kernel.org
Signed-off-by: Joe Thornber <ejt@redhat.com>
Tested-by: Ming-Hung Tsai <mtsai@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Otherwise most non-x86 architectures (e.g. riscv, arm) will resort to
byte-by-byte access.
Cc: stable@vger.kernel.org
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Remove this extra BUG_ON() that calls node_check() -- which avoids extra crc checking.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Both sm_disk_new_block and sm_disk_commit are needlessly calling
sm_disk_get_nr_free(). Looks like old queries used for some
debugging.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
NULL pointer dereference was observed in super_written() when it tries
to access the mddev structure.
[The below stack trace is from an older kernel, but the problem described
in this patch applies to the mainline kernel.]
[ 1194.474861] task: ffff8fdd20858000 task.stack: ffffb99d40790000
[ 1194.488000] RIP: 0010:super_written+0x29/0xe1
[ 1194.499688] RSP: 0018:ffff8ffb7fcc3c78 EFLAGS: 00010046
[ 1194.512477] RAX: 0000000000000000 RBX: ffff8ffb7bf4a000 RCX: ffff8ffb78991048
[ 1194.527325] RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff8ffb56b8a200
[ 1194.542576] RBP: ffff8ffb7fcc3c90 R08: 000000000000000b R09: 0000000000000000
[ 1194.558001] R10: ffff8ffb56b8a298 R11: 0000000000000000 R12: ffff8ffb56b8a200
[ 1194.573070] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 1194.588117] FS: 0000000000000000(0000) GS:ffff8ffb7fcc0000(0000) knlGS:0000000000000000
[ 1194.604264] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1194.617375] CR2: 00000000000002b8 CR3: 00000021e040a002 CR4: 00000000007606e0
[ 1194.632327] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1194.647865] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1194.663316] PKRU: 55555554
[ 1194.674090] Call Trace:
[ 1194.683735] <IRQ>
[ 1194.692948] bio_endio+0xae/0x135
[ 1194.703580] blk_update_request+0xad/0x2fa
[ 1194.714990] blk_update_bidi_request+0x20/0x72
[ 1194.726578] __blk_end_bidi_request+0x2c/0x4d
[ 1194.738373] __blk_end_request_all+0x31/0x49
[ 1194.749344] blk_flush_complete_seq+0x377/0x383
[ 1194.761550] flush_end_io+0x1dd/0x2a7
[ 1194.772910] blk_finish_request+0x9f/0x13c
[ 1194.784544] scsi_end_request+0x180/0x25c
[ 1194.796149] scsi_io_completion+0xc8/0x610
[ 1194.807503] scsi_finish_command+0xdc/0x125
[ 1194.818897] scsi_softirq_done+0x81/0xde
[ 1194.830062] blk_done_softirq+0xa4/0xcc
[ 1194.841008] __do_softirq+0xd9/0x29f
[ 1194.851257] irq_exit+0xe6/0xeb
[ 1194.861290] do_IRQ+0x59/0xe3
[ 1194.871060] common_interrupt+0x1c6/0x382
[ 1194.881988] </IRQ>
[ 1194.890646] RIP: 0010:cpuidle_enter_state+0xdd/0x2a5
[ 1194.902532] RSP: 0018:ffffb99d40793e68 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff43
[ 1194.917317] RAX: ffff8ffb7fce27c0 RBX: ffff8ffb7fced800 RCX: 000000000000001f
[ 1194.932056] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000000
[ 1194.946428] RBP: ffffb99d40793ea0 R08: 0000000000000004 R09: 0000000000002ed2
[ 1194.960508] R10: 0000000000002664 R11: 0000000000000018 R12: 0000000000000003
[ 1194.974454] R13: 000000000000000b R14: ffffffff925715a0 R15: 0000011610120d5a
[ 1194.988607] ? cpuidle_enter_state+0xcc/0x2a5
[ 1194.999077] cpuidle_enter+0x17/0x19
[ 1195.008395] call_cpuidle+0x23/0x3a
[ 1195.017718] do_idle+0x172/0x1d5
[ 1195.026358] cpu_startup_entry+0x73/0x75
[ 1195.035769] start_secondary+0x1b9/0x20b
[ 1195.044894] secondary_startup_64+0xa5/0xa5
[ 1195.084921] RIP: super_written+0x29/0xe1 RSP: ffff8ffb7fcc3c78
[ 1195.096354] CR2: 00000000000002b8
bio in the above stack is a bitmap write whose completion is invoked after
the tear down sequence sets the mddev structure to NULL in rdev.
During tear down, there is an attempt to flush the bitmap writes, but for
external bitmaps, there is no explicit wait for all the bitmap writes to
complete. For instance, md_bitmap_flush() is called to flush the bitmap
writes, but the last call to md_bitmap_daemon_work() in md_bitmap_flush()
could generate new bitmap writes for which there is no explicit wait to
complete those writes. The call to md_bitmap_update_sb() will return
simply for external bitmaps and the follow-up call to md_update_sb() is
conditional and may not get called for external bitmaps. This results in a
kernel panic when the completion routine, super_written() is called which
tries to reference mddev in the rdev that has been set to
NULL(in unbind_rdev_from_array() by tear down sequence).
The solution is to call md_super_wait() for external bitmaps after the
last call to md_bitmap_daemon_work() in md_bitmap_flush() to ensure there
are no pending bitmap writes before proceeding with the tear down.
Cc: stable@vger.kernel.org
Signed-off-by: Sudhakar Panneerselvam <sudhakar.panneerselvam@oracle.com>
Reviewed-by: Zhao Heming <heming.zhao@suse.com>
Signed-off-by: Song Liu <song@kernel.org>
Instead of returning an existing mddev, just for it to be discarded
later directly return -EEXIST. Rename the function to mddev_alloc now
that it doesn't find an existing mddev.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>
Allocate the new mddev first speculatively, which greatly simplifies
the code flow.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>
Split out a self contained helper to find a free minor for the md
"unit" number.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>
commit df7b59ba92 ("dm verity: fix FEC for RS roots unaligned to
block size") introduced the possibility for misaligned roots IO
relative to the underlying device's logical block size. E.g. Android's
default RS roots=2 results in dm_bufio->block_size=1024, which causes
the following EIO if the logical block size of the device is 4096,
given v->data_dev_block_bits=12:
E sd 0 : 0:0:0: [sda] tag#30 request not aligned to the logical block size
E blk_update_request: I/O error, dev sda, sector 10368424 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
E device-mapper: verity-fec: 254:8: FEC 9244672: parity read failed (block 18056): -5
Fix this by onlu using f->roots for dm_bufio blocksize IFF it is
aligned to v->data_dev_block_bits.
Fixes: df7b59ba92 ("dm verity: fix FEC for RS roots unaligned to block size")
Cc: stable@vger.kernel.org
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
The patch "bcache: remove PTR_CACHE" introduces a compiling failure in
debug.c with following error message,
In file included from drivers/md/bcache/bcache.h:182:0,
from drivers/md/bcache/debug.c:9:
drivers/md/bcache/debug.c: In function 'bch_btree_verify':
drivers/md/bcache/debug.c:53:19: error: 'c' undeclared (first use in
this function)
bio_set_dev(bio, c->cache->bdev);
^
This patch fixes the regression by replacing c->cache->bdev by b->c->
cache->bdev.
Signed-off-by: Coly Li <colyli@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210411134316.80274-8-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Cast multiple variables to (int64_t) in order to give the compiler
complete information about the proper arithmetic to use. Notice that
these variables are being used in contexts that expect expressions of
type int64_t (64 bit, signed). And currently, such expressions are
being evaluated using 32-bit arithmetic.
Fixes: d0cf9503e9 ("octeontx2-pf: ethtool fec mode support")
Addresses-Coverity-ID: 1501724 ("Unintentional integer overflow")
Addresses-Coverity-ID: 1501725 ("Unintentional integer overflow")
Addresses-Coverity-ID: 1501726 ("Unintentional integer overflow")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20210411134316.80274-7-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
building with 'make W=1' shows a harmless warning for each user of the
EBUG_ON() macro:
drivers/md/bcache/bset.c: In function 'bch_btree_sort_partial':
drivers/md/bcache/util.h:30:55: error: suggest braces around empty body in an 'if' statement [-Werror=empty-body]
30 | #define EBUG_ON(cond) do { if (cond); } while (0)
| ^
drivers/md/bcache/bset.c:1312:9: note: in expansion of macro 'EBUG_ON'
1312 | EBUG_ON(oldsize >= 0 && bch_count_data(b) != oldsize);
| ^~~~~~~
Reword the macro slightly to avoid the warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20210411134316.80274-5-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This fixes the following sparse warnings:
drivers/md/bcache/features.c:22:16: warning: Using plain integer as NULL
pointer
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20210411134316.80274-4-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Remove the PTR_CACHE inline and replace it with a direct dereference
of c->cache.
(Coly Li: fix the typo from PTR_BUCKET to PTR_CACHE in commit log)
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20210411134316.80274-3-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In bch_cached_dev_run(), free(env[1])|free(env[2])|free(buf)
show up three times. This patch introduce out tag in
which free(env[1])|free(env[2])|free(buf) are only called
one time. If we need to call free() when errors occur,
we can set error code to ret, and then goto out tag directly.
Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20210411134316.80274-2-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
list_sort() internally casts the comparison function passed to it
to a different type with constant struct list_head pointers, and
uses this pointer to call the functions, which trips indirect call
Control-Flow Integrity (CFI) checking.
Instead of removing the consts, this change defines the
list_cmp_func_t type and changes the comparison function types of
all list_sort() callers to use const pointers, thus avoiding type
mismatches.
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210408182843.1754385-10-samitolvanen@google.com
Split mddev_find into a simple mddev_find that just finds an existing
mddev by the unit number, and a more complicated mddev_find that deals
with find or allocating a mddev.
This turns out to fix this bug reported by Zhao Heming.
----------------------------- snip ------------------------------
commit d3374825ce ("md: make devices disappear when they are no longer
needed.") introduced protection between mddev creating & removing. The
md_open shouldn't create mddev when all_mddevs list doesn't contain
mddev. With currently code logic, there will be very easy to trigger
soft lockup in non-preempt env.
*** env ***
kvm-qemu VM 2C1G with 2 iscsi luns
kernel should be non-preempt
*** script ***
about trigger 1 time with 10 tests
`1 node1="15sp3-mdcluster1"
2 node2="15sp3-mdcluster2"
3
4 mdadm -Ss
5 ssh ${node2} "mdadm -Ss"
6 wipefs -a /dev/sda /dev/sdb
7 mdadm -CR /dev/md0 -b clustered -e 1.2 -n 2 -l mirror /dev/sda \
/dev/sdb --assume-clean
8
9 for i in {1..100}; do
10 echo ==== $i ====;
11
12 echo "test ...."
13 ssh ${node2} "mdadm -A /dev/md0 /dev/sda /dev/sdb"
14 sleep 1
15
16 echo "clean ....."
17 ssh ${node2} "mdadm -Ss"
18 done
`
I use mdcluster env to trigger soft lockup, but it isn't mdcluster
speical bug. To stop md array in mdcluster env will do more jobs than
non-cluster array, which will leave enough time/gap to allow kernel to
run md_open.
*** stack ***
`ID: 2831 TASK: ffff8dd7223b5040 CPU: 0 COMMAND: "mdadm"
#0 [ffffa15d00a13b90] __schedule at ffffffffb8f1935f
#1 [ffffa15d00a13ba8] exact_lock at ffffffffb8a4a66d
#2 [ffffa15d00a13bb0] kobj_lookup at ffffffffb8c62fe3
#3 [ffffa15d00a13c28] __blkdev_get at ffffffffb89273b9
#4 [ffffa15d00a13c98] blkdev_get at ffffffffb8927964
#5 [ffffa15d00a13cb0] do_dentry_open at ffffffffb88dc4b4
#6 [ffffa15d00a13ce0] path_openat at ffffffffb88f0ccc
#7 [ffffa15d00a13db8] do_filp_open at ffffffffb88f32bb
#8 [ffffa15d00a13ee0] do_sys_open at ffffffffb88ddc7d
#9 [ffffa15d00a13f38] do_syscall_64 at ffffffffb86053cb ffffffffb900008c
or:
[ 884.226509] mddev_put+0x1c/0xe0 [md_mod]
[ 884.226515] md_open+0x3c/0xe0 [md_mod]
[ 884.226518] __blkdev_get+0x30d/0x710
[ 884.226520] ? bd_acquire+0xd0/0xd0
[ 884.226522] blkdev_get+0x14/0x30
[ 884.226524] do_dentry_open+0x204/0x3a0
[ 884.226531] path_openat+0x2fc/0x1520
[ 884.226534] ? seq_printf+0x4e/0x70
[ 884.226536] do_filp_open+0x9b/0x110
[ 884.226542] ? md_release+0x20/0x20 [md_mod]
[ 884.226543] ? seq_read+0x1d8/0x3e0
[ 884.226545] ? kmem_cache_alloc+0x18a/0x270
[ 884.226547] ? do_sys_open+0x1bd/0x260
[ 884.226548] do_sys_open+0x1bd/0x260
[ 884.226551] do_syscall_64+0x5b/0x1e0
[ 884.226554] entry_SYSCALL_64_after_hwframe+0x44/0xa9
`
*** rootcause ***
"mdadm -A" (or other array assemble commands) will start a daemon "mdadm
--monitor" by default. When "mdadm -Ss" is running, the stop action will
wakeup "mdadm --monitor". The "--monitor" daemon will immediately get
info from /proc/mdstat. This time mddev in kernel still exist, so
/proc/mdstat still show md device, which makes "mdadm --monitor" to open
/dev/md0.
The previously "mdadm -Ss" is removing action, the "mdadm --monitor"
open action will trigger md_open which is creating action. Racing is
happening.
`<thread 1>: "mdadm -Ss"
md_release
mddev_put deletes mddev from all_mddevs
queue_work for mddev_delayed_delete
at this time, "/dev/md0" is still available for opening
<thread 2>: "mdadm --monitor ..."
md_open
+ mddev_find can't find mddev of /dev/md0, and create a new mddev and
| return.
+ trigger "if (mddev->gendisk != bdev->bd_disk)" and return
-ERESTARTSYS.
`
In non-preempt kernel, <thread 2> is occupying on current CPU. and
mddev_delayed_delete which was created in <thread 1> also can't be
schedule.
In preempt kernel, it can also trigger above racing. But kernel doesn't
allow one thread running on a CPU all the time. after <thread 2> running
some time, the later "mdadm -A" (refer above script line 13) will call
md_alloc to alloc a new gendisk for mddev. it will break md_open
statement "if (mddev->gendisk != bdev->bd_disk)" and return 0 to caller,
the soft lockup is broken.
------------------------------ snip ------------------------------
Cc: stable@vger.kernel.org
Fixes: d3374825ce ("md: make devices disappear when they are no longer needed.")
Reported-by: Heming Zhao <heming.zhao@suse.com>
Reviewed-by: Heming Zhao <heming.zhao@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>
Factor out a self-contained helper to just lookup a mddev by the dev_t
"unit".
Cc: stable@vger.kernel.org
Reviewed-by: Heming Zhao <heming.zhao@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>
commit d3374825ce ("md: make devices disappear when they are no longer
needed.") introduced protection between mddev creating & removing. The
md_open shouldn't create mddev when all_mddevs list doesn't contain
mddev. With currently code logic, there will be very easy to trigger
soft lockup in non-preempt env.
This patch changes md_open returning from -ERESTARTSYS to -EBUSY, which
will break the infinitely retry when md_open enter racing area.
This patch is partly fix soft lockup issue, full fix needs mddev_find
is split into two functions: mddev_find & mddev_find_or_alloc. And
md_open should call new mddev_find (it only does searching job).
For more detail, please refer with Christoph's "split mddev_find" patch
in later commits.
*** env ***
kvm-qemu VM 2C1G with 2 iscsi luns
kernel should be non-preempt
*** script ***
about trigger every time with below script
```
1 node1="mdcluster1"
2 node2="mdcluster2"
3
4 mdadm -Ss
5 ssh ${node2} "mdadm -Ss"
6 wipefs -a /dev/sda /dev/sdb
7 mdadm -CR /dev/md0 -b clustered -e 1.2 -n 2 -l mirror /dev/sda \
/dev/sdb --assume-clean
8
9 for i in {1..10}; do
10 echo ==== $i ====;
11
12 echo "test ...."
13 ssh ${node2} "mdadm -A /dev/md0 /dev/sda /dev/sdb"
14 sleep 1
15
16 echo "clean ....."
17 ssh ${node2} "mdadm -Ss"
18 done
```
I use mdcluster env to trigger soft lockup, but it isn't mdcluster
speical bug. To stop md array in mdcluster env will do more jobs than
non-cluster array, which will leave enough time/gap to allow kernel to
run md_open.
*** stack ***
```
[ 884.226509] mddev_put+0x1c/0xe0 [md_mod]
[ 884.226515] md_open+0x3c/0xe0 [md_mod]
[ 884.226518] __blkdev_get+0x30d/0x710
[ 884.226520] ? bd_acquire+0xd0/0xd0
[ 884.226522] blkdev_get+0x14/0x30
[ 884.226524] do_dentry_open+0x204/0x3a0
[ 884.226531] path_openat+0x2fc/0x1520
[ 884.226534] ? seq_printf+0x4e/0x70
[ 884.226536] do_filp_open+0x9b/0x110
[ 884.226542] ? md_release+0x20/0x20 [md_mod]
[ 884.226543] ? seq_read+0x1d8/0x3e0
[ 884.226545] ? kmem_cache_alloc+0x18a/0x270
[ 884.226547] ? do_sys_open+0x1bd/0x260
[ 884.226548] do_sys_open+0x1bd/0x260
[ 884.226551] do_syscall_64+0x5b/0x1e0
[ 884.226554] entry_SYSCALL_64_after_hwframe+0x44/0xa9
```
*** rootcause ***
"mdadm -A" (or other array assemble commands) will start a daemon "mdadm
--monitor" by default. When "mdadm -Ss" is running, the stop action will
wakeup "mdadm --monitor". The "--monitor" daemon will immediately get
info from /proc/mdstat. This time mddev in kernel still exist, so
/proc/mdstat still show md device, which makes "mdadm --monitor" to open
/dev/md0.
The previously "mdadm -Ss" is removing action, the "mdadm --monitor"
open action will trigger md_open which is creating action. Racing is
happening.
```
<thread 1>: "mdadm -Ss"
md_release
mddev_put deletes mddev from all_mddevs
queue_work for mddev_delayed_delete
at this time, "/dev/md0" is still available for opening
<thread 2>: "mdadm --monitor ..."
md_open
+ mddev_find can't find mddev of /dev/md0, and create a new mddev and
| return.
+ trigger "if (mddev->gendisk != bdev->bd_disk)" and return
-ERESTARTSYS.
```
In non-preempt kernel, <thread 2> is occupying on current CPU. and
mddev_delayed_delete which was created in <thread 1> also can't be
schedule.
In preempt kernel, it can also trigger above racing. But kernel doesn't
allow one thread running on a CPU all the time. after <thread 2> running
some time, the later "mdadm -A" (refer above script line 13) will call
md_alloc to alloc a new gendisk for mddev. it will break md_open
statement "if (mddev->gendisk != bdev->bd_disk)" and return 0 to caller,
the soft lockup is broken.
Cc: stable@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Zhao Heming <heming.zhao@suse.com>
Signed-off-by: Song Liu <song@kernel.org>
Add a new flag "reset_recalculate" that will restart recalculating
from the beginning of the device. It can be used if we want to change
the hash function. Example:
dmsetup remove_all
rmmod brd
set -e
modprobe brd rd_size=1048576
dmsetup create in --table '0 2000000 integrity /dev/ram0 0 16 J 2 internal_hash:sha256 recalculate'
sleep 10
dmsetup status
dmsetup remove in
dmsetup create in --table '0 2000000 integrity /dev/ram0 0 16 J 2 internal_hash:sha3-256 reset_recalculate'
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
