| 4a4bba9f | 19-Nov-2023 |
Coly Li <colyli@suse.de> |
bcache: avoid NULL checking to c->root in run_cache_set()
[ Upstream commit 3eba5e0b2422aec3c9e79822029599961fdcab97 ]
In run_cache_set() after c->root returned from bch_btree_node_get(), it
is che
bcache: avoid NULL checking to c->root in run_cache_set()
[ Upstream commit 3eba5e0b2422aec3c9e79822029599961fdcab97 ]
In run_cache_set() after c->root returned from bch_btree_node_get(), it
is checked by IS_ERR_OR_NULL(). Indeed it is unncessary to check NULL
because bch_btree_node_get() will not return NULL pointer to caller.
This patch replaces IS_ERR_OR_NULL() by IS_ERR() for the above reason.
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20231120052503.6122-11-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
show more ...
|
| 66534172 | 19-Nov-2023 |
Colin Ian King <colin.i.king@gmail.com> |
bcache: remove redundant assignment to variable cur_idx
[ Upstream commit be93825f0e6428c2d3f03a6e4d447dc48d33d7ff ]
Variable cur_idx is being initialized with a value that is never read,
it is bei
bcache: remove redundant assignment to variable cur_idx
[ Upstream commit be93825f0e6428c2d3f03a6e4d447dc48d33d7ff ]
Variable cur_idx is being initialized with a value that is never read,
it is being re-assigned later in a while-loop. Remove the redundant
assignment. Cleans up clang scan build warning:
drivers/md/bcache/writeback.c:916:2: warning: Value stored to 'cur_idx'
is never read [deadcode.DeadStores]
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Coly Li <colyli@suse.de>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20231120052503.6122-4-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
show more ...
|
| b163173d | 19-Nov-2023 |
Mingzhe Zou <mingzhe.zou@easystack.cn> |
bcache: fixup lock c->root error
commit e34820f984512b433ee1fc291417e60c47d56727 upstream.
We had a problem with io hung because it was waiting for c->root to
release the lock.
crash> cache_set.ro
bcache: fixup lock c->root error
commit e34820f984512b433ee1fc291417e60c47d56727 upstream.
We had a problem with io hung because it was waiting for c->root to
release the lock.
crash> cache_set.root -l cache_set.list ffffa03fde4c0050
root = 0xffff802ef454c800
crash> btree -o 0xffff802ef454c800 | grep rw_semaphore
[ffff802ef454c858] struct rw_semaphore lock;
crash> struct rw_semaphore ffff802ef454c858
struct rw_semaphore {
count = {
counter = -4294967297
},
wait_list = {
next = 0xffff00006786fc28,
prev = 0xffff00005d0efac8
},
wait_lock = {
raw_lock = {
{
val = {
counter = 0
},
{
locked = 0 '\000',
pending = 0 '\000'
},
{
locked_pending = 0,
tail = 0
}
}
}
},
osq = {
tail = {
counter = 0
}
},
owner = 0xffffa03fdc586603
}
The "counter = -4294967297" means that lock count is -1 and a write lock
is being attempted. Then, we found that there is a btree with a counter
of 1 in btree_cache_freeable.
crash> cache_set -l cache_set.list ffffa03fde4c0050 -o|grep btree_cache
[ffffa03fde4c1140] struct list_head btree_cache;
[ffffa03fde4c1150] struct list_head btree_cache_freeable;
[ffffa03fde4c1160] struct list_head btree_cache_freed;
[ffffa03fde4c1170] unsigned int btree_cache_used;
[ffffa03fde4c1178] wait_queue_head_t btree_cache_wait;
[ffffa03fde4c1190] struct task_struct *btree_cache_alloc_lock;
crash> list -H ffffa03fde4c1140|wc -l
973
crash> list -H ffffa03fde4c1150|wc -l
1123
crash> cache_set.btree_cache_used -l cache_set.list ffffa03fde4c0050
btree_cache_used = 2097
crash> list -s btree -l btree.list -H ffffa03fde4c1140|grep -E -A2 "^ lock = {" > btree_cache.txt
crash> list -s btree -l btree.list -H ffffa03fde4c1150|grep -E -A2 "^ lock = {" > btree_cache_freeable.txt
[root@node-3 127.0.0.1-2023-08-04-16:40:28]# pwd
/var/crash/127.0.0.1-2023-08-04-16:40:28
[root@node-3 127.0.0.1-2023-08-04-16:40:28]# cat btree_cache.txt|grep counter|grep -v "counter = 0"
[root@node-3 127.0.0.1-2023-08-04-16:40:28]# cat btree_cache_freeable.txt|grep counter|grep -v "counter = 0"
counter = 1
We found that this is a bug in bch_sectors_dirty_init() when locking c->root:
(1). Thread X has locked c->root(A) write.
(2). Thread Y failed to lock c->root(A), waiting for the lock(c->root A).
(3). Thread X bch_btree_set_root() changes c->root from A to B.
(4). Thread X releases the lock(c->root A).
(5). Thread Y successfully locks c->root(A).
(6). Thread Y releases the lock(c->root B).
down_write locked ---(1)----------------------┐
| |
| down_read waiting ---(2)----┐ |
| | ┌-------------┐ ┌-------------┐
bch_btree_set_root ===(3)========>> | c->root A | | c->root B |
| | └-------------┘ └-------------┘
up_write ---(4)---------------------┘ | |
| | |
down_read locked ---(5)-----------┘ |
| |
up_read ---(6)-----------------------------┘
Since c->root may change, the correct steps to lock c->root should be
the same as bch_root_usage(), compare after locking.
static unsigned int bch_root_usage(struct cache_set *c)
{
unsigned int bytes = 0;
struct bkey *k;
struct btree *b;
struct btree_iter iter;
goto lock_root;
do {
rw_unlock(false, b);
lock_root:
b = c->root;
rw_lock(false, b, b->level);
} while (b != c->root);
for_each_key_filter(&b->keys, k, &iter, bch_ptr_bad)
bytes += bkey_bytes(k);
rw_unlock(false, b);
return (bytes * 100) / btree_bytes(c);
}
Fixes: b144e45fc576 ("bcache: make bch_sectors_dirty_init() to be multithreaded")
Signed-off-by: Mingzhe Zou <mingzhe.zou@easystack.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20231120052503.6122-7-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
show more ...
|
| 19aff881 | 19-Nov-2023 |
Mingzhe Zou <mingzhe.zou@easystack.cn> |
bcache: fixup init dirty data errors
commit 7cc47e64d3d69786a2711a4767e26b26ba63d7ed upstream.
We found that after long run, the dirty_data of the bcache device
will have errors. This error cannot
bcache: fixup init dirty data errors
commit 7cc47e64d3d69786a2711a4767e26b26ba63d7ed upstream.
We found that after long run, the dirty_data of the bcache device
will have errors. This error cannot be eliminated unless re-register.
We also found that reattach after detach, this error can accumulate.
In bch_sectors_dirty_init(), all inode <= d->id keys will be recounted
again. This is wrong, we only need to count the keys of the current
device.
Fixes: b144e45fc576 ("bcache: make bch_sectors_dirty_init() to be multithreaded")
Signed-off-by: Mingzhe Zou <mingzhe.zou@easystack.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20231120052503.6122-6-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
show more ...
|
| 8ff25310 | 19-Nov-2023 |
Rand Deeb <rand.sec96@gmail.com> |
bcache: prevent potential division by zero error
commit 2c7f497ac274a14330208b18f6f734000868ebf9 upstream.
In SHOW(), the variable 'n' is of type 'size_t.' While there is a
conditional check to ver
bcache: prevent potential division by zero error
commit 2c7f497ac274a14330208b18f6f734000868ebf9 upstream.
In SHOW(), the variable 'n' is of type 'size_t.' While there is a
conditional check to verify that 'n' is not equal to zero before
executing the 'do_div' macro, concerns arise regarding potential
division by zero error in 64-bit environments.
The concern arises when 'n' is 64 bits in size, greater than zero, and
the lower 32 bits of it are zeros. In such cases, the conditional check
passes because 'n' is non-zero, but the 'do_div' macro casts 'n' to
'uint32_t,' effectively truncating it to its lower 32 bits.
Consequently, the 'n' value becomes zero.
To fix this potential division by zero error and ensure precise
division handling, this commit replaces the 'do_div' macro with
div64_u64(). div64_u64() is designed to work with 64-bit operands,
guaranteeing that division is performed correctly.
This change enhances the robustness of the code, ensuring that division
operations yield accurate results in all scenarios, eliminating the
possibility of division by zero, and improving compatibility across
different 64-bit environments.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Signed-off-by: Rand Deeb <rand.sec96@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20231120052503.6122-5-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
show more ...
|
| d1280fd4 | 19-Nov-2023 |
Mingzhe Zou <mingzhe.zou@easystack.cn> |
bcache: fixup multi-threaded bch_sectors_dirty_init() wake-up race
commit 2faac25d7958c4761bb8cec54adb79f806783ad6 upstream.
We get a kernel crash about "unable to handle kernel paging request":
`
bcache: fixup multi-threaded bch_sectors_dirty_init() wake-up race
commit 2faac25d7958c4761bb8cec54adb79f806783ad6 upstream.
We get a kernel crash about "unable to handle kernel paging request":
```dmesg
[368033.032005] BUG: unable to handle kernel paging request at ffffffffad9ae4b5
[368033.032007] PGD fc3a0d067 P4D fc3a0d067 PUD fc3a0e063 PMD 8000000fc38000e1
[368033.032012] Oops: 0003 [#1] SMP PTI
[368033.032015] CPU: 23 PID: 55090 Comm: bch_dirtcnt[0] Kdump: loaded Tainted: G OE --------- - - 4.18.0-147.5.1.es8_24.x86_64 #1
[368033.032017] Hardware name: Tsinghua Tongfang THTF Chaoqiang Server/072T6D, BIOS 2.4.3 01/17/2017
[368033.032027] RIP: 0010:native_queued_spin_lock_slowpath+0x183/0x1d0
[368033.032029] Code: 8b 02 48 85 c0 74 f6 48 89 c1 eb d0 c1 e9 12 83 e0
03 83 e9 01 48 c1 e0 05 48 63 c9 48 05 c0 3d 02 00 48 03 04 cd 60 68 93
ad <48> 89 10 8b 42 08 85 c0 75 09 f3 90 8b 42 08 85 c0 74 f7 48 8b 02
[368033.032031] RSP: 0018:ffffbb48852abe00 EFLAGS: 00010082
[368033.032032] RAX: ffffffffad9ae4b5 RBX: 0000000000000246 RCX: 0000000000003bf3
[368033.032033] RDX: ffff97b0ff8e3dc0 RSI: 0000000000600000 RDI: ffffbb4884743c68
[368033.032034] RBP: 0000000000000001 R08: 0000000000000000 R09: 000007ffffffffff
[368033.032035] R10: ffffbb486bb01000 R11: 0000000000000001 R12: ffffffffc068da70
[368033.032036] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000000
[368033.032038] FS: 0000000000000000(0000) GS:ffff97b0ff8c0000(0000) knlGS:0000000000000000
[368033.032039] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[368033.032040] CR2: ffffffffad9ae4b5 CR3: 0000000fc3a0a002 CR4: 00000000003626e0
[368033.032042] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[368033.032043] bcache: bch_cached_dev_attach() Caching rbd479 as bcache462 on set 8cff3c36-4a76-4242-afaa-7630206bc70b
[368033.032045] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[368033.032046] Call Trace:
[368033.032054] _raw_spin_lock_irqsave+0x32/0x40
[368033.032061] __wake_up_common_lock+0x63/0xc0
[368033.032073] ? bch_ptr_invalid+0x10/0x10 [bcache]
[368033.033502] bch_dirty_init_thread+0x14c/0x160 [bcache]
[368033.033511] ? read_dirty_submit+0x60/0x60 [bcache]
[368033.033516] kthread+0x112/0x130
[368033.033520] ? kthread_flush_work_fn+0x10/0x10
[368033.034505] ret_from_fork+0x35/0x40
```
The crash occurred when call wake_up(&state->wait), and then we want
to look at the value in the state. However, bch_sectors_dirty_init()
is not found in the stack of any task. Since state is allocated on
the stack, we guess that bch_sectors_dirty_init() has exited, causing
bch_dirty_init_thread() to be unable to handle kernel paging request.
In order to verify this idea, we added some printing information during
wake_up(&state->wait). We find that "wake up" is printed twice, however
we only expect the last thread to wake up once.
```dmesg
[ 994.641004] alcache: bch_dirty_init_thread() wake up
[ 994.641018] alcache: bch_dirty_init_thread() wake up
[ 994.641523] alcache: bch_sectors_dirty_init() init exit
```
There is a race. If bch_sectors_dirty_init() exits after the first wake
up, the second wake up will trigger this bug("unable to handle kernel
paging request").
Proceed as follows:
bch_sectors_dirty_init
kthread_run ==============> bch_dirty_init_thread(bch_dirtcnt[0])
... ...
atomic_inc(&state.started) ...
... ...
atomic_read(&state.enough) ...
... atomic_set(&state->enough, 1)
kthread_run ======================================================> bch_dirty_init_thread(bch_dirtcnt[1])
... atomic_dec_and_test(&state->started) ...
atomic_inc(&state.started) ... ...
... wake_up(&state->wait) ...
atomic_read(&state.enough) atomic_dec_and_test(&state->started)
... ...
wait_event(state.wait, atomic_read(&state.started) == 0) ...
return ...
wake_up(&state->wait)
We believe it is very common to wake up twice if there is no dirty, but
crash is an extremely low probability event. It's hard for us to reproduce
this issue. We attached and detached continuously for a week, with a total
of more than one million attaches and only one crash.
Putting atomic_inc(&state.started) before kthread_run() can avoid waking
up twice.
Fixes: b144e45fc576 ("bcache: make bch_sectors_dirty_init() to be multithreaded")
Signed-off-by: Mingzhe Zou <mingzhe.zou@easystack.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20231120052503.6122-8-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
show more ...
|
| f0854489 | 15-Jun-2023 |
Mingzhe Zou <mingzhe.zou@easystack.cn> |
bcache: fixup btree_cache_wait list damage
We get a kernel crash about "list_add corruption. next->prev should be
prev (ffff9c801bc01210), but was ffff9c77b688237c.
(next=ffffae586d8afe68)."
crash>
bcache: fixup btree_cache_wait list damage
We get a kernel crash about "list_add corruption. next->prev should be
prev (ffff9c801bc01210), but was ffff9c77b688237c.
(next=ffffae586d8afe68)."
crash> struct list_head 0xffff9c801bc01210
struct list_head {
next = 0xffffae586d8afe68,
prev = 0xffffae586d8afe68
}
crash> struct list_head 0xffff9c77b688237c
struct list_head {
next = 0x0,
prev = 0x0
}
crash> struct list_head 0xffffae586d8afe68
struct list_head struct: invalid kernel virtual address: ffffae586d8afe68 type: "gdb_readmem_callback"
Cannot access memory at address 0xffffae586d8afe68
[230469.019492] Call Trace:
[230469.032041] prepare_to_wait+0x8a/0xb0
[230469.044363] ? bch_btree_keys_free+0x6c/0xc0 [escache]
[230469.056533] mca_cannibalize_lock+0x72/0x90 [escache]
[230469.068788] mca_alloc+0x2ae/0x450 [escache]
[230469.080790] bch_btree_node_get+0x136/0x2d0 [escache]
[230469.092681] bch_btree_check_thread+0x1e1/0x260 [escache]
[230469.104382] ? finish_wait+0x80/0x80
[230469.115884] ? bch_btree_check_recurse+0x1a0/0x1a0 [escache]
[230469.127259] kthread+0x112/0x130
[230469.138448] ? kthread_flush_work_fn+0x10/0x10
[230469.149477] ret_from_fork+0x35/0x40
bch_btree_check_thread() and bch_dirty_init_thread() may call
mca_cannibalize() to cannibalize other cached btree nodes. Only one thread
can do it at a time, so the op of other threads will be added to the
btree_cache_wait list.
We must call finish_wait() to remove op from btree_cache_wait before free
it's memory address. Otherwise, the list will be damaged. Also should call
bch_cannibalize_unlock() to release the btree_cache_alloc_lock and wake_up
other waiters.
Fixes: 8e7102273f59 ("bcache: make bch_btree_check() to be multithreaded")
Fixes: b144e45fc576 ("bcache: make bch_sectors_dirty_init() to be multithreaded")
Cc: stable@vger.kernel.org
Signed-off-by: Mingzhe Zou <mingzhe.zou@easystack.cn>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20230615121223.22502-7-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
show more ...
|
| 80fca8a1 | 15-Jun-2023 |
Zheng Wang <zyytlz.wz@163.com> |
bcache: Fix __bch_btree_node_alloc to make the failure behavior consistent
In some specific situations, the return value of __bch_btree_node_alloc
may be NULL. This may lead to a potential NULL poin
bcache: Fix __bch_btree_node_alloc to make the failure behavior consistent
In some specific situations, the return value of __bch_btree_node_alloc
may be NULL. This may lead to a potential NULL pointer dereference in
caller function like a calling chain :
btree_split->bch_btree_node_alloc->__bch_btree_node_alloc.
Fix it by initializing the return value in __bch_btree_node_alloc.
Fixes: cafe56359144 ("bcache: A block layer cache")
Cc: stable@vger.kernel.org
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20230615121223.22502-6-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
show more ...
|
| 028ddcac | 15-Jun-2023 |
Zheng Wang <zyytlz.wz@163.com> |
bcache: Remove unnecessary NULL point check in node allocations
Due to the previous fix of __bch_btree_node_alloc, the return value will
never be a NULL pointer. So IS_ERR is enough to handle the fa
bcache: Remove unnecessary NULL point check in node allocations
Due to the previous fix of __bch_btree_node_alloc, the return value will
never be a NULL pointer. So IS_ERR is enough to handle the failure
situation. Fix it by replacing IS_ERR_OR_NULL check by an IS_ERR check.
Fixes: cafe56359144 ("bcache: A block layer cache")
Cc: stable@vger.kernel.org
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20230615121223.22502-5-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
show more ...
|
| ccb8c3bd | 15-Jun-2023 |
Andrea Tomassetti <andrea.tomassetti-opensource@devo.com> |
bcache: Remove dead references to cache_readaheads
The cache_readaheads stat counter is not used anymore and should be
removed.
Signed-off-by: Andrea Tomassetti <andrea.tomassetti-opensource@devo.c
bcache: Remove dead references to cache_readaheads
The cache_readaheads stat counter is not used anymore and should be
removed.
Signed-off-by: Andrea Tomassetti <andrea.tomassetti-opensource@devo.com>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20230615121223.22502-4-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
show more ...
|
| b98dd0b0 | 15-Jun-2023 |
Thomas Weißschuh <linux@weissschuh.net> |
bcache: make kobj_type structures constant
Since commit ee6d3dd4ed48 ("driver core: make kobj_type constant.")
the driver core allows the usage of const struct kobj_type.
Take advantage of this to
bcache: make kobj_type structures constant
Since commit ee6d3dd4ed48 ("driver core: make kobj_type constant.")
the driver core allows the usage of const struct kobj_type.
Take advantage of this to constify the structure definitions to prevent
modification at runtime.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20230615121223.22502-3-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
show more ...
|