linux-stable.git/drivers/block, branch v6.6.67 Linux kernel stable tree zram: clear IDLE flag in mark_idle() 2024-12-14T18:59:44+00:00 Sergey Senozhatsky senozhatsky@chromium.org 2024-10-28T15:36:15+00:00 7360a0e798f4806794e7bd3b507bf4d82e0b07ad [ Upstream commit d37da422edb0664a2037e6d7d42fe6d339aae78a ] If entry does not fulfill current mark_idle() parameters, e.g. cutoff time, then we should clear its ZRAM_IDLE from previous mark_idle() invocations. Consider the following case: - mark_idle() cutoff time 8h - mark_idle() cutoff time 4h - writeback() idle - will writeback entries with cutoff time 8h, while it should only pick entries with cutoff time 4h The bug was reported by Shin Kawamura. Link: https://lkml.kernel.org/r/20241028153629.1479791-3-senozhatsky@chromium.org Fixes: 755804d16965 ("zram: introduce an aged idle interface") Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> Reported-by: Shin Kawamura <kawasin@google.com> Acked-by: Brian Geffon <bgeffon@google.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: <stable@vger.kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit d37da422edb0664a2037e6d7d42fe6d339aae78a ]

If entry does not fulfill current mark_idle() parameters, e.g.  cutoff
time, then we should clear its ZRAM_IDLE from previous mark_idle()
invocations.

Consider the following case:
- mark_idle() cutoff time 8h
- mark_idle() cutoff time 4h
- writeback() idle - will writeback entries with cutoff time 8h,
  while it should only pick entries with cutoff time 4h

The bug was reported by Shin Kawamura.

Link: https://lkml.kernel.org/r/20241028153629.1479791-3-senozhatsky@chromium.org
Fixes: 755804d16965 ("zram: introduce an aged idle interface")
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reported-by: Shin Kawamura <kawasin@google.com>
Acked-by: Brian Geffon <bgeffon@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
zram: do not mark idle slots that cannot be idle 2024-12-14T18:59:44+00:00 Sergey Senozhatsky senozhatsky@chromium.org 2024-09-17T02:09:10+00:00 9c251d1381ed81f5da84be3d5ed0eaca62147af8 [ Upstream commit b967fa1ba72b5da2b6d9bf95f0b13420a59e0701 ] ZRAM_SAME slots cannot be post-processed (writeback or recompress) so do not mark them ZRAM_IDLE. Same with ZRAM_WB slots, they cannot be ZRAM_IDLE because they are not in zsmalloc pool anymore. Link: https://lkml.kernel.org/r/20240917021020.883356-6-senozhatsky@chromium.org Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Stable-dep-of: d37da422edb0 ("zram: clear IDLE flag in mark_idle()") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit b967fa1ba72b5da2b6d9bf95f0b13420a59e0701 ]

ZRAM_SAME slots cannot be post-processed (writeback or recompress) so do
not mark them ZRAM_IDLE.  Same with ZRAM_WB slots, they cannot be
ZRAM_IDLE because they are not in zsmalloc pool anymore.

Link: https://lkml.kernel.org/r/20240917021020.883356-6-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: d37da422edb0 ("zram: clear IDLE flag in mark_idle()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
zram: split memory-tracking and ac-time tracking 2024-12-14T18:59:44+00:00 Sergey Senozhatsky senozhatsky@chromium.org 2023-11-15T02:42:12+00:00 b7c3fd65a3eaa7a7639ddec8b817a824e814bf37 [ Upstream commit a7a0350583ba51d8cde6180bb51d704b89a3b29e ] ZRAM_MEMORY_TRACKING enables two features: - per-entry ac-time tracking - debugfs interface The latter one is the reason why memory-tracking depends on DEBUG_FS, while the former one is used far beyond debugging these days. Namely ac-time is used for fine grained writeback of idle entries (pages). Move ac-time tracking under its own config option so that it can be enabled (along with writeback) on systems without DEBUG_FS. [senozhatsky@chromium.org: ifdef fixup, per Dmytro] Link: https://lkml.kernel.org/r/20231117013543.540280-1-senozhatsky@chromium.org Link: https://lkml.kernel.org/r/20231115024223.4133148-1-senozhatsky@chromium.org Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Dmytro Maluka <dmaluka@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Stable-dep-of: d37da422edb0 ("zram: clear IDLE flag in mark_idle()") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit a7a0350583ba51d8cde6180bb51d704b89a3b29e ]

ZRAM_MEMORY_TRACKING enables two features:
- per-entry ac-time tracking
- debugfs interface

The latter one is the reason why memory-tracking depends on DEBUG_FS,
while the former one is used far beyond debugging these days.  Namely
ac-time is used for fine grained writeback of idle entries (pages).

Move ac-time tracking under its own config option so that it can be
enabled (along with writeback) on systems without DEBUG_FS.

[senozhatsky@chromium.org: ifdef fixup, per Dmytro]
  Link: https://lkml.kernel.org/r/20231117013543.540280-1-senozhatsky@chromium.org
Link: https://lkml.kernel.org/r/20231115024223.4133148-1-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dmytro Maluka <dmaluka@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: d37da422edb0 ("zram: clear IDLE flag in mark_idle()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
zram: clear IDLE flag after recompression 2024-12-09T09:33:05+00:00 Sergey Senozhatsky senozhatsky@chromium.org 2024-10-28T15:36:14+00:00 9a8b989d8958f1771d79c351df9f082184e3c46f commit f85219096648b251a81e9fe24a1974590cfc417d upstream. Patch series "zram: IDLE flag handling fixes", v2. zram can wrongly preserve ZRAM_IDLE flag on its entries which can result in premature post-processing (writeback and recompression) of such entries. This patch (of 2) Recompression should clear ZRAM_IDLE flag on the entries it has accessed, because otherwise some entries, specifically those for which recompression has failed, become immediate candidate entries for another post-processing (e.g. writeback). Consider the following case: - recompression marks entries IDLE every 4 hours and attempts to recompress them - some entries are incompressible, so we keep them intact and hence preserve IDLE flag - writeback marks entries IDLE every 8 hours and writebacks IDLE entries, however we have IDLE entries left from recompression, so writeback prematurely writebacks those entries. The bug was reported by Shin Kawamura. Link: https://lkml.kernel.org/r/20241028153629.1479791-1-senozhatsky@chromium.org Link: https://lkml.kernel.org/r/20241028153629.1479791-2-senozhatsky@chromium.org Fixes: 84b33bf78889 ("zram: introduce recompress sysfs knob") Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> Reported-by: Shin Kawamura <kawasin@google.com> Acked-by: Brian Geffon <bgeffon@google.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit f85219096648b251a81e9fe24a1974590cfc417d upstream.

Patch series "zram: IDLE flag handling fixes", v2.

zram can wrongly preserve ZRAM_IDLE flag on its entries which can result
in premature post-processing (writeback and recompression) of such
entries.

This patch (of 2)

Recompression should clear ZRAM_IDLE flag on the entries it has accessed,
because otherwise some entries, specifically those for which recompression
has failed, become immediate candidate entries for another post-processing
(e.g.  writeback).

Consider the following case:
- recompression marks entries IDLE every 4 hours and attempts
  to recompress them
- some entries are incompressible, so we keep them intact and
  hence preserve IDLE flag
- writeback marks entries IDLE every 8 hours and writebacks
  IDLE entries, however we have IDLE entries left from
  recompression, so writeback prematurely writebacks those
  entries.

The bug was reported by Shin Kawamura.

Link: https://lkml.kernel.org/r/20241028153629.1479791-1-senozhatsky@chromium.org
Link: https://lkml.kernel.org/r/20241028153629.1479791-2-senozhatsky@chromium.org
Fixes: 84b33bf78889 ("zram: introduce recompress sysfs knob")
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reported-by: Shin Kawamura <kawasin@google.com>
Acked-by: Brian Geffon <bgeffon@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ublk: fix error code for unsupported command 2024-12-09T09:32:53+00:00 Ming Lei ming.lei@redhat.com 2024-11-19T03:06:46+00:00 9e68fcffc764551e64f6ab28bd75d67a7f58f18f commit 34c1227035b3ab930a1ae6ab6f22fec1af8ab09e upstream. ENOTSUPP is for kernel use only, and shouldn't be sent to userspace. Fix it by replacing it with EOPNOTSUPP. Cc: stable@vger.kernel.org Fixes: bfbcef036396 ("ublk_drv: move ublk_get_device_from_id into ublk_ctrl_uring_cmd") Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20241119030646.2319030-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 34c1227035b3ab930a1ae6ab6f22fec1af8ab09e upstream.

ENOTSUPP is for kernel use only, and shouldn't be sent to userspace.

Fix it by replacing it with EOPNOTSUPP.

Cc: stable@vger.kernel.org
Fixes: bfbcef036396 ("ublk_drv: move ublk_get_device_from_id into ublk_ctrl_uring_cmd")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20241119030646.2319030-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ublk: fix ublk_ch_mmap() for 64K page size 2024-12-09T09:32:50+00:00 Ming Lei ming.lei@redhat.com 2024-11-11T11:07:18+00:00 80f25003af2269af9d58fb2face5439d95368e4f commit d369735e02ef122d19d4c3d093028da0eb400636 upstream. In ublk_ch_mmap(), queue id is calculated in the following way: (vma->vm_pgoff << PAGE_SHIFT) / `max_cmd_buf_size` 'max_cmd_buf_size' is equal to `UBLK_MAX_QUEUE_DEPTH * sizeof(struct ublksrv_io_desc)` and UBLK_MAX_QUEUE_DEPTH is 4096 and part of UAPI, so 'max_cmd_buf_size' is always page aligned in 4K page size kernel. However, it isn't true in 64K page size kernel. Fixes the issue by always rounding up 'max_cmd_buf_size' with PAGE_SIZE. Cc: stable@vger.kernel.org Fixes: 71f28f3136af ("ublk_drv: add io_uring based userspace block driver") Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20241111110718.1394001-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit d369735e02ef122d19d4c3d093028da0eb400636 upstream.

In ublk_ch_mmap(), queue id is calculated in the following way:

	(vma->vm_pgoff << PAGE_SHIFT) / `max_cmd_buf_size`

'max_cmd_buf_size' is equal to

	`UBLK_MAX_QUEUE_DEPTH * sizeof(struct ublksrv_io_desc)`

and UBLK_MAX_QUEUE_DEPTH is 4096 and part of UAPI, so 'max_cmd_buf_size'
is always page aligned in 4K page size kernel. However, it isn't true in
64K page size kernel.

Fixes the issue by always rounding up 'max_cmd_buf_size' with PAGE_SIZE.

Cc: stable@vger.kernel.org
Fixes: 71f28f3136af ("ublk_drv: add io_uring based userspace block driver")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20241111110718.1394001-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
virtio_blk: reverse request order in virtio_queue_rqs 2024-12-09T09:31:46+00:00 Christoph Hellwig hch@lst.de 2024-11-13T15:20:42+00:00 b2c36fa9ac8a7daa8cb1f374ab72ec540c286ed2 [ Upstream commit 7f212e997edbb7a2cb85cef2ac14265dfaf88717 ] blk_mq_flush_plug_list submits requests in the reverse order that they were submitted, which leads to a rather suboptimal I/O pattern especially in rotational devices. Fix this by rewriting virtio_queue_rqs so that it always pops the requests from the passed in request list, and then adds them to the head of a local submit list. This actually simplifies the code a bit as it removes the complicated list splicing, at the cost of extra updates of the rq_next pointer. As that should be cache hot anyway it should be an easy price to pay. Fixes: 0e9911fa768f ("virtio-blk: support mq_ops->queue_rqs()") Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20241113152050.157179-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 7f212e997edbb7a2cb85cef2ac14265dfaf88717 ]

blk_mq_flush_plug_list submits requests in the reverse order that they
were submitted, which leads to a rather suboptimal I/O pattern
especially in rotational devices. Fix this by rewriting virtio_queue_rqs
so that it always pops the requests from the passed in request list, and
then adds them to the head of a local submit list. This actually
simplifies the code a bit as it removes the complicated list splicing,
at the cost of extra updates of the rq_next pointer. As that should be
cache hot anyway it should be an easy price to pay.

Fixes: 0e9911fa768f ("virtio-blk: support mq_ops->queue_rqs()")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20241113152050.157179-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
brd: defer automatic disk creation until module initialization succeeds 2024-12-09T09:31:43+00:00 Yang Erkun yangerkun@huawei.com 2024-10-30T03:49:14+00:00 410896624db639500f24f46478b4bfa05c76bf56 [ Upstream commit 826cc42adf44930a633d11a5993676d85ddb0842 ] My colleague Wupeng found the following problems during fault injection: BUG: unable to handle page fault for address: fffffbfff809d073 PGD 6e648067 P4D 123ec8067 PUD 123ec4067 PMD 100e38067 PTE 0 Oops: Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI CPU: 5 UID: 0 PID: 755 Comm: modprobe Not tainted 6.12.0-rc3+ #17 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 RIP: 0010:__asan_load8+0x4c/0xa0 ... Call Trace: <TASK> blkdev_put_whole+0x41/0x70 bdev_release+0x1a3/0x250 blkdev_release+0x11/0x20 __fput+0x1d7/0x4a0 task_work_run+0xfc/0x180 syscall_exit_to_user_mode+0x1de/0x1f0 do_syscall_64+0x6b/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e loop_init() is calling loop_add() after __register_blkdev() succeeds and is ignoring disk_add() failure from loop_add(), for loop_add() failure is not fatal and successfully created disks are already visible to bdev_open(). brd_init() is currently calling brd_alloc() before __register_blkdev() succeeds and is releasing successfully created disks when brd_init() returns an error. This can cause UAF for the latter two case: case 1: T1: modprobe brd brd_init brd_alloc(0) // success add_disk disk_scan_partitions bdev_file_open_by_dev // alloc file fput // won't free until back to userspace brd_alloc(1) // failed since mem alloc error inject // error path for modprobe will release code segment // back to userspace __fput blkdev_release bdev_release blkdev_put_whole bdev->bd_disk->fops->release // fops is freed now, UAF! case 2: T1: T2: modprobe brd brd_init brd_alloc(0) // success open(/dev/ram0) brd_alloc(1) // fail // error path for modprobe close(/dev/ram0) ... /* UAF! */ bdev->bd_disk->fops->release Fix this problem by following what loop_init() does. Besides, reintroduce brd_devices_mutex to help serialize modifications to brd_list. Fixes: 7f9b348cb5e9 ("brd: convert to blk_alloc_disk/blk_cleanup_disk") Reported-by: Wupeng Ma <mawupeng1@huawei.com> Signed-off-by: Yang Erkun <yangerkun@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20241030034914.907829-1-yangerkun@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 826cc42adf44930a633d11a5993676d85ddb0842 ]

My colleague Wupeng found the following problems during fault injection:

BUG: unable to handle page fault for address: fffffbfff809d073
PGD 6e648067 P4D 123ec8067 PUD 123ec4067 PMD 100e38067 PTE 0
Oops: Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 5 UID: 0 PID: 755 Comm: modprobe Not tainted 6.12.0-rc3+ #17
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.16.1-2.fc37 04/01/2014
RIP: 0010:__asan_load8+0x4c/0xa0
...
Call Trace:
 <TASK>
 blkdev_put_whole+0x41/0x70
 bdev_release+0x1a3/0x250
 blkdev_release+0x11/0x20
 __fput+0x1d7/0x4a0
 task_work_run+0xfc/0x180
 syscall_exit_to_user_mode+0x1de/0x1f0
 do_syscall_64+0x6b/0x170
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

loop_init() is calling loop_add() after __register_blkdev() succeeds and
is ignoring disk_add() failure from loop_add(), for loop_add() failure
is not fatal and successfully created disks are already visible to
bdev_open().

brd_init() is currently calling brd_alloc() before __register_blkdev()
succeeds and is releasing successfully created disks when brd_init()
returns an error. This can cause UAF for the latter two case:

case 1:
    T1:
modprobe brd
  brd_init
    brd_alloc(0) // success
      add_disk
        disk_scan_partitions
          bdev_file_open_by_dev // alloc file
          fput // won't free until back to userspace
    brd_alloc(1) // failed since mem alloc error inject
  // error path for modprobe will release code segment
  // back to userspace
  __fput
    blkdev_release
      bdev_release
        blkdev_put_whole
          bdev->bd_disk->fops->release // fops is freed now, UAF!

case 2:
    T1:                            T2:
modprobe brd
  brd_init
    brd_alloc(0) // success
                                   open(/dev/ram0)
    brd_alloc(1) // fail
  // error path for modprobe

                                   close(/dev/ram0)
                                   ...
                                   /* UAF! */
                                   bdev->bd_disk->fops->release

Fix this problem by following what loop_init() does. Besides,
reintroduce brd_devices_mutex to help serialize modifications to
brd_list.

Fixes: 7f9b348cb5e9 ("brd: convert to blk_alloc_disk/blk_cleanup_disk")
Reported-by: Wupeng Ma <mawupeng1@huawei.com>
Signed-off-by: Yang Erkun <yangerkun@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20241030034914.907829-1-yangerkun@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
ublk: don't allow user copy for unprivileged device 2024-10-22T13:46:27+00:00 Ming Lei ming.lei@redhat.com 2024-10-16T13:48:47+00:00 6414ab5c9c9c068eca6dc4fd3a036bc4b83164dc commit 42aafd8b48adac1c3b20fe5892b1b91b80c1a1e6 upstream. UBLK_F_USER_COPY requires userspace to call write() on ublk char device for filling request buffer, and unprivileged device can't be trusted. So don't allow user copy for unprivileged device. Cc: stable@vger.kernel.org Fixes: 1172d5b8beca ("ublk: support user copy") Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20241016134847.2911721-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 42aafd8b48adac1c3b20fe5892b1b91b80c1a1e6 upstream.

UBLK_F_USER_COPY requires userspace to call write() on ublk char
device for filling request buffer, and unprivileged device can't
be trusted.

So don't allow user copy for unprivileged device.

Cc: stable@vger.kernel.org
Fixes: 1172d5b8beca ("ublk: support user copy")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20241016134847.2911721-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
zram: don't free statically defined names 2024-10-17T13:24:14+00:00 Andrey Skvortsov andrej.skvortzov@gmail.com 2024-10-09T04:51:40+00:00 6e20720b12299595154857fa98222729f0d5823c [ Upstream commit 486fd58af7ac1098b68370b1d4d9f94a2a1c7124 ] When CONFIG_ZRAM_MULTI_COMP isn't set ZRAM_SECONDARY_COMP can hold default_compressor, because it's the same offset as ZRAM_PRIMARY_COMP, so we need to make sure that we don't attempt to kfree() the statically defined compressor name. This is detected by KASAN. ================================================================== Call trace: kfree+0x60/0x3a0 zram_destroy_comps+0x98/0x198 [zram] zram_reset_device+0x22c/0x4a8 [zram] reset_store+0x1bc/0x2d8 [zram] dev_attr_store+0x44/0x80 sysfs_kf_write+0xfc/0x188 kernfs_fop_write_iter+0x28c/0x428 vfs_write+0x4dc/0x9b8 ksys_write+0x100/0x1f8 __arm64_sys_write+0x74/0xb8 invoke_syscall+0xd8/0x260 el0_svc_common.constprop.0+0xb4/0x240 do_el0_svc+0x48/0x68 el0_svc+0x40/0xc8 el0t_64_sync_handler+0x120/0x130 el0t_64_sync+0x190/0x198 ================================================================== Link: https://lkml.kernel.org/r/20240923164843.1117010-1-andrej.skvortzov@gmail.com Fixes: 684826f8271a ("zram: free secondary algorithms names") Signed-off-by: Andrey Skvortsov <andrej.skvortzov@gmail.com> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> Reported-by: Venkat Rao Bagalkote <venkat88@linux.vnet.ibm.com> Closes: https://lore.kernel.org/lkml/57130e48-dbb6-4047-a8c7-ebf5aaea93f4@linux.vnet.ibm.com/ Tested-by: Venkat Rao Bagalkote <venkat88@linux.vnet.ibm.com> Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Cc: Jens Axboe <axboe@kernel.dk> Cc: Minchan Kim <minchan@kernel.org> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Venkat Rao Bagalkote <venkat88@linux.vnet.ibm.com> Cc: Chris Li <chrisl@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 486fd58af7ac1098b68370b1d4d9f94a2a1c7124 ]

When CONFIG_ZRAM_MULTI_COMP isn't set ZRAM_SECONDARY_COMP can hold
default_compressor, because it's the same offset as ZRAM_PRIMARY_COMP, so
we need to make sure that we don't attempt to kfree() the statically
defined compressor name.

This is detected by KASAN.

==================================================================
  Call trace:
   kfree+0x60/0x3a0
   zram_destroy_comps+0x98/0x198 [zram]
   zram_reset_device+0x22c/0x4a8 [zram]
   reset_store+0x1bc/0x2d8 [zram]
   dev_attr_store+0x44/0x80
   sysfs_kf_write+0xfc/0x188
   kernfs_fop_write_iter+0x28c/0x428
   vfs_write+0x4dc/0x9b8
   ksys_write+0x100/0x1f8
   __arm64_sys_write+0x74/0xb8
   invoke_syscall+0xd8/0x260
   el0_svc_common.constprop.0+0xb4/0x240
   do_el0_svc+0x48/0x68
   el0_svc+0x40/0xc8
   el0t_64_sync_handler+0x120/0x130
   el0t_64_sync+0x190/0x198
==================================================================

Link: https://lkml.kernel.org/r/20240923164843.1117010-1-andrej.skvortzov@gmail.com
Fixes: 684826f8271a ("zram: free secondary algorithms names")
Signed-off-by: Andrey Skvortsov <andrej.skvortzov@gmail.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reported-by: Venkat Rao Bagalkote <venkat88@linux.vnet.ibm.com>
Closes: https://lore.kernel.org/lkml/57130e48-dbb6-4047-a8c7-ebf5aaea93f4@linux.vnet.ibm.com/
Tested-by: Venkat Rao Bagalkote <venkat88@linux.vnet.ibm.com>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Venkat Rao Bagalkote <venkat88@linux.vnet.ibm.com>
Cc: Chris Li <chrisl@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>