linux-stable.git/drivers/md/bcache, branch linux-5.4.y

bcache: revert replacing IS_ERR_OR_NULL with IS_ERR again

2024-12-14T18:44:49+00:00

commit b2e382ae12a63560fca35050498e19e760adf8c0 upstream.

Commit 028ddcac477b ("bcache: Remove unnecessary NULL point check in
node allocations") leads a NULL pointer deference in cache_set_flush().

1721         if (!IS_ERR_OR_NULL(c->root))
1722                 list_add(&c->root->list, &c->btree_cache);

>From the above code in cache_set_flush(), if previous registration code
fails before allocating c->root, it is possible c->root is NULL as what
it is initialized. __bch_btree_node_alloc() never returns NULL but
c->root is possible to be NULL at above line 1721.

This patch replaces IS_ERR() by IS_ERR_OR_NULL() to fix this.

Fixes: 028ddcac477b ("bcache: Remove unnecessary NULL point check in node allocations")
Signed-off-by: Liequan Che 
Cc: stable@vger.kernel.org
Cc: Zheng Wang 
Reviewed-by: Mingzhe Zou 
Signed-off-by: Coly Li 
Link: https://lore.kernel.org/r/20241202115638.28957-1-colyli@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: avoid NULL checking to c->root in run_cache_set()

2023-12-20T14:41:20+00:00

[ 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 
Link: https://lore.kernel.org/r/20231120052503.6122-11-colyli@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

bcache: add code comments for bch_btree_node_get() and __bch_btree_node_alloc()

2023-12-20T14:41:20+00:00

[ Upstream commit 31f5b956a197d4ec25c8a07cb3a2ab69d0c0b82f ]

This patch adds code comments to bch_btree_node_get() and
__bch_btree_node_alloc() that NULL pointer will not be returned and it
is unnecessary to check NULL pointer by the callers of these routines.

Signed-off-by: Coly Li 
Link: https://lore.kernel.org/r/20231120052503.6122-10-colyli@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

bcache: avoid oversize memory allocation by small stripe_size

2023-12-20T14:41:20+00:00

[ Upstream commit baf8fb7e0e5ec54ea0839f0c534f2cdcd79bea9c ]

Arraies bcache->stripe_sectors_dirty and bcache->full_dirty_stripes are
used for dirty data writeback, their sizes are decided by backing device
capacity and stripe size. Larger backing device capacity or smaller
stripe size make these two arraies occupies more dynamic memory space.

Currently bcache->stripe_size is directly inherited from
queue->limits.io_opt of underlying storage device. For normal hard
drives, its limits.io_opt is 0, and bcache sets the corresponding
stripe_size to 1TB (1<<31 sectors), it works fine 10+ years. But for
devices do declare value for queue->limits.io_opt, small stripe_size
(comparing to 1TB) becomes an issue for oversize memory allocations of
bcache->stripe_sectors_dirty and bcache->full_dirty_stripes, while the
capacity of hard drives gets much larger in recent decade.

For example a raid5 array assembled by three 20TB hardrives, the raid
device capacity is 40TB with typical 512KB limits.io_opt. After the math
calculation in bcache code, these two arraies will occupy 400MB dynamic
memory. Even worse Andrea Tomassetti reports that a 4KB limits.io_opt is
declared on a new 2TB hard drive, then these two arraies request 2GB and
512MB dynamic memory from kzalloc(). The result is that bcache device
always fails to initialize on his system.

To avoid the oversize memory allocation, bcache->stripe_size should not
directly inherited by queue->limits.io_opt from the underlying device.
This patch defines BCH_MIN_STRIPE_SZ (4MB) as minimal bcache stripe size
and set bcache device's stripe size against the declared limits.io_opt
value from the underlying storage device,
- If the declared limits.io_opt > BCH_MIN_STRIPE_SZ, bcache device will
  set its stripe size directly by this limits.io_opt value.
- If the declared limits.io_opt < BCH_MIN_STRIPE_SZ, bcache device will
  set its stripe size by a value multiplying limits.io_opt and euqal or
  large than BCH_MIN_STRIPE_SZ.

Then the minimal stripe size of a bcache device will always be >= 4MB.
For a 40TB raid5 device with 512KB limits.io_opt, memory occupied by
bcache->stripe_sectors_dirty and bcache->full_dirty_stripes will be 50MB
in total. For a 2TB hard drive with 4KB limits.io_opt, memory occupied
by these two arraies will be 2.5MB in total.

Such mount of memory allocated for bcache->stripe_sectors_dirty and
bcache->full_dirty_stripes is reasonable for most of storage devices.

Reported-by: Andrea Tomassetti 
Signed-off-by: Coly Li 
Reviewed-by: Eric Wheeler 
Link: https://lore.kernel.org/r/20231120052503.6122-2-colyli@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

bcache: revert replacing IS_ERR_OR_NULL with IS_ERR

2023-12-08T07:44:26+00:00

commit bb6cc253861bd5a7cf8439e2118659696df9619f upstream.

Commit 028ddcac477b ("bcache: Remove unnecessary NULL point check in
node allocations") replaced IS_ERR_OR_NULL by IS_ERR. This leads to a
NULL pointer dereference.

BUG: kernel NULL pointer dereference, address: 0000000000000080
Call Trace:
 ? __die_body.cold+0x1a/0x1f
 ? page_fault_oops+0xd2/0x2b0
 ? exc_page_fault+0x70/0x170
 ? asm_exc_page_fault+0x22/0x30
 ? btree_node_free+0xf/0x160 [bcache]
 ? up_write+0x32/0x60
 btree_gc_coalesce+0x2aa/0x890 [bcache]
 ? bch_extent_bad+0x70/0x170 [bcache]
 btree_gc_recurse+0x130/0x390 [bcache]
 ? btree_gc_mark_node+0x72/0x230 [bcache]
 bch_btree_gc+0x5da/0x600 [bcache]
 ? cpuusage_read+0x10/0x10
 ? bch_btree_gc+0x600/0x600 [bcache]
 bch_gc_thread+0x135/0x180 [bcache]

The relevant code starts with:

    new_nodes[0] = NULL;

    for (i = 0; i < nodes; i++) {
        if (__bch_keylist_realloc(&keylist, bkey_u64s(&r[i].b->key)))
            goto out_nocoalesce;
    // ...
out_nocoalesce:
    // ...
    for (i = 0; i < nodes; i++)
        if (!IS_ERR(new_nodes[i])) {  // IS_ERR_OR_NULL before
028ddcac477b
            btree_node_free(new_nodes[i]);  // new_nodes[0] is NULL
            rw_unlock(true, new_nodes[i]);
        }

This patch replaces IS_ERR() by IS_ERR_OR_NULL() to fix this.

Fixes: 028ddcac477b ("bcache: Remove unnecessary NULL point check in node allocations")
Link: https://lore.kernel.org/all/3DF4A87A-2AC1-4893-AE5F-E921478419A9@suse.de/
Cc: stable@vger.kernel.org
Cc: Zheng Wang 
Cc: Coly Li 
Signed-off-by: Markus Weippert 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: prevent potential division by zero error

2023-12-08T07:44:25+00:00

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 
Cc:  
Signed-off-by: Coly Li 
Link: https://lore.kernel.org/r/20231120052503.6122-5-colyli@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: check return value from btree_node_alloc_replacement()

2023-12-08T07:44:25+00:00

commit 777967e7e9f6f5f3e153abffb562bffaf4430d26 upstream.

In btree_gc_rewrite_node(), pointer 'n' is not checked after it returns
from btree_gc_rewrite_node(). There is potential possibility that 'n' is
a non NULL ERR_PTR(), referencing such error code is not permitted in
following code. Therefore a return value checking is necessary after 'n'
is back from btree_node_alloc_replacement().

Signed-off-by: Coly Li 
Reported-by: Dan Carpenter 
Cc:  
Link: https://lore.kernel.org/r/20231120052503.6122-3-colyli@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: replace a mistaken IS_ERR() by IS_ERR_OR_NULL() in btree_gc_coalesce()

2023-12-08T07:44:25+00:00

commit f72f4312d4388376fc8a1f6cf37cb21a0d41758b upstream.

Commit 028ddcac477b ("bcache: Remove unnecessary NULL point check in
node allocations") do the following change inside btree_gc_coalesce(),

31 @@ -1340,7 +1340,7 @@ static int btree_gc_coalesce(
32         memset(new_nodes, 0, sizeof(new_nodes));
33         closure_init_stack(&cl);
34
35 -       while (nodes < GC_MERGE_NODES && !IS_ERR_OR_NULL(r[nodes].b))
36 +       while (nodes < GC_MERGE_NODES && !IS_ERR(r[nodes].b))
37                 keys += r[nodes++].keys;
38
39         blocks = btree_default_blocks(b->c) * 2 / 3;

At line 35 the original r[nodes].b is not always allocatored from
__bch_btree_node_alloc(), and possibly initialized as NULL pointer by
caller of btree_gc_coalesce(). Therefore the change at line 36 is not
correct.

This patch replaces the mistaken IS_ERR() by IS_ERR_OR_NULL() to avoid
potential issue.

Fixes: 028ddcac477b ("bcache: Remove unnecessary NULL point check in node allocations")
Cc:   # 6.5+
Cc: Zheng Wang 
Signed-off-by: Coly Li 
Link: https://lore.kernel.org/r/20231120052503.6122-9-colyli@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

bcache: Fix __bch_btree_node_alloc to make the failure behavior consistent

2023-08-11T09:53:44+00:00

[ Upstream commit 80fca8a10b604afad6c14213fdfd816c4eda3ee4 ]

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 
Signed-off-by: Coly Li 
Link: https://lore.kernel.org/r/20230615121223.22502-6-colyli@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

bcache: remove 'int n' from parameter list of bch_bucket_alloc_set()

2023-08-11T09:53:44+00:00

[ Upstream commit 17e4aed8309ff28670271546c2c3263eb12f5eb6 ]

The parameter 'int n' from bch_bucket_alloc_set() is not cleared
defined. From the code comments n is the number of buckets to alloc, but
from the code itself 'n' is the maximum cache to iterate. Indeed all the
locations where bch_bucket_alloc_set() is called, 'n' is alwasy 1.

This patch removes the confused and unnecessary 'int n' from parameter
list of  bch_bucket_alloc_set(), and explicitly allocates only 1 bucket
for its caller.

Signed-off-by: Coly Li 
Reviewed-by: Hannes Reinecke 
Signed-off-by: Jens Axboe 
Stable-dep-of: 80fca8a10b60 ("bcache: Fix __bch_btree_node_alloc to make the failure behavior consistent")
Signed-off-by: Sasha Levin