linux.git/block, branch v6.6.39

block/ioctl: prefer different overflow check

2024-06-27T11:49:01+00:00

[ Upstream commit ccb326b5f9e623eb7f130fbbf2505ec0e2dcaff9 ]

Running syzkaller with the newly reintroduced signed integer overflow
sanitizer shows this report:

[   62.982337] ------------[ cut here ]------------
[   62.985692] cgroup: Invalid name
[   62.986211] UBSAN: signed-integer-overflow in ../block/ioctl.c:36:46
[   62.989370] 9pnet_fd: p9_fd_create_tcp (7343): problem connecting socket to 127.0.0.1
[   62.992992] 9223372036854775807 + 4095 cannot be represented in type 'long long'
[   62.997827] 9pnet_fd: p9_fd_create_tcp (7345): problem connecting socket to 127.0.0.1
[   62.999369] random: crng reseeded on system resumption
[   63.000634] GUP no longer grows the stack in syz-executor.2 (7353): 20002000-20003000 (20001000)
[   63.000668] CPU: 0 PID: 7353 Comm: syz-executor.2 Not tainted 6.8.0-rc2-00035-gb3ef86b5a957 #1
[   63.000677] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[   63.000682] Call Trace:
[   63.000686]  
[   63.000731]  dump_stack_lvl+0x93/0xd0
[   63.000919]  __get_user_pages+0x903/0xd30
[   63.001030]  __gup_longterm_locked+0x153e/0x1ba0
[   63.001041]  ? _raw_read_unlock_irqrestore+0x17/0x50
[   63.001072]  ? try_get_folio+0x29c/0x2d0
[   63.001083]  internal_get_user_pages_fast+0x1119/0x1530
[   63.001109]  iov_iter_extract_pages+0x23b/0x580
[   63.001206]  bio_iov_iter_get_pages+0x4de/0x1220
[   63.001235]  iomap_dio_bio_iter+0x9b6/0x1410
[   63.001297]  __iomap_dio_rw+0xab4/0x1810
[   63.001316]  iomap_dio_rw+0x45/0xa0
[   63.001328]  ext4_file_write_iter+0xdde/0x1390
[   63.001372]  vfs_write+0x599/0xbd0
[   63.001394]  ksys_write+0xc8/0x190
[   63.001403]  do_syscall_64+0xd4/0x1b0
[   63.001421]  ? arch_exit_to_user_mode_prepare+0x3a/0x60
[   63.001479]  entry_SYSCALL_64_after_hwframe+0x6f/0x77
[   63.001535] RIP: 0033:0x7f7fd3ebf539
[   63.001551] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 14 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
[   63.001562] RSP: 002b:00007f7fd32570c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[   63.001584] RAX: ffffffffffffffda RBX: 00007f7fd3ff3f80 RCX: 00007f7fd3ebf539
[   63.001590] RDX: 4db6d1e4f7e43360 RSI: 0000000020000000 RDI: 0000000000000004
[   63.001595] RBP: 00007f7fd3f1e496 R08: 0000000000000000 R09: 0000000000000000
[   63.001599] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
[   63.001604] R13: 0000000000000006 R14: 00007f7fd3ff3f80 R15: 00007ffd415ad2b8
...
[   63.018142] ---[ end trace ]---

Historically, the signed integer overflow sanitizer did not work in the
kernel due to its interaction with `-fwrapv` but this has since been
changed [1] in the newest version of Clang; It was re-enabled in the
kernel with Commit 557f8c582a9ba8ab ("ubsan: Reintroduce signed overflow
sanitizer").

Let's rework this overflow checking logic to not actually perform an
overflow during the check itself, thus avoiding the UBSAN splat.

[1]: https://github.com/llvm/llvm-project/pull/82432

Signed-off-by: Justin Stitt 
Reviewed-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20240507-b4-sio-block-ioctl-v3-1-ba0c2b32275e@google.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: fix request.queuelist usage in flush

2024-06-21T12:38:35+00:00

[ Upstream commit d0321c812d89c5910d8da8e4b10c891c6b96ff70 ]

Friedrich Weber reported a kernel crash problem and bisected to commit
81ada09cc25e ("blk-flush: reuse rq queuelist in flush state machine").

The root cause is that we use "list_move_tail(&rq->queuelist, pending)"
in the PREFLUSH/POSTFLUSH sequences. But rq->queuelist.next == xxx since
it's popped out from plug->cached_rq in __blk_mq_alloc_requests_batch().
We don't initialize its queuelist just for this first request, although
the queuelist of all later popped requests will be initialized.

Fix it by changing to use "list_add_tail(&rq->queuelist, pending)" so
rq->queuelist doesn't need to be initialized. It should be ok since rq
can't be on any list when PREFLUSH or POSTFLUSH, has no move actually.

Please note the commit 81ada09cc25e ("blk-flush: reuse rq queuelist in
flush state machine") also has another requirement that no drivers would
touch rq->queuelist after blk_mq_end_request() since we will reuse it to
add rq to the post-flush pending list in POSTFLUSH. If this is not true,
we will have to revert that commit IMHO.

This updated version adds "list_del_init(&rq->queuelist)" in flush rq
callback since the dm layer may submit request of a weird invalid format
(REQ_FSEQ_PREFLUSH | REQ_FSEQ_POSTFLUSH), which causes double list_add
if without this "list_del_init(&rq->queuelist)". The weird invalid format
problem should be fixed in dm layer.

Reported-by: Friedrich Weber 
Closes: https://lore.kernel.org/lkml/14b89dfb-505c-49f7-aebb-01c54451db40@proxmox.com/
Closes: https://lore.kernel.org/lkml/c9d03ff7-27c5-4ebd-b3f6-5a90d96f35ba@proxmox.com/
Fixes: 81ada09cc25e ("blk-flush: reuse rq queuelist in flush state machine")
Cc: Christoph Hellwig 
Cc: ming.lei@redhat.com
Cc: bvanassche@acm.org
Tested-by: Friedrich Weber 
Signed-off-by: Chengming Zhou 
Reviewed-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20240608143115.972486-1-chengming.zhou@linux.dev
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: sed-opal: avoid possible wrong address reference in read_sed_opal_key()

2024-06-21T12:38:35+00:00

[ Upstream commit 9b1ebce6a1fded90d4a1c6c57dc6262dac4c4c14 ]

Clang static checker (scan-build) warning:
block/sed-opal.c:line 317, column 3
Value stored to 'ret' is never read.

Fix this problem by returning the error code when keyring_search() failed.
Otherwise, 'key' will have a wrong value when 'kerf' stores the error code.

Fixes: 3bfeb6125664 ("block: sed-opal: keyring support for SED keys")
Signed-off-by: Su Hui 
Link: https://lore.kernel.org/r/20240611073659.429582-1-suhui@nfschina.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

blk-cgroup: Properly propagate the iostat update up the hierarchy

2024-06-12T09:12:46+00:00

[ Upstream commit 9d230c09964e6e18c8f6e4f0d41ee90eef45ec1c ]

During a cgroup_rstat_flush() call, the lowest level of nodes are flushed
first before their parents. Since commit 3b8cc6298724 ("blk-cgroup:
Optimize blkcg_rstat_flush()"), iostat propagation was still done to
the parent. Grandparent, however, may not get the iostat update if the
parent has no blkg_iostat_set queued in its lhead lockless list.

Fix this iostat propagation problem by queuing the parent's global
blkg->iostat into one of its percpu lockless lists to make sure that
the delta will always be propagated up to the grandparent and so on
toward the root blkcg.

Note that successive calls to __blkcg_rstat_flush() are serialized by
the cgroup_rstat_lock. So no special barrier is used in the reading
and writing of blkg->iostat.lqueued.

Fixes: 3b8cc6298724 ("blk-cgroup: Optimize blkcg_rstat_flush()")
Reported-by: Dan Schatzberg 
Closes: https://lore.kernel.org/lkml/ZkO6l%2FODzadSgdhC@dschatzberg-fedora-PF3DHTBV/
Signed-off-by: Waiman Long 
Reviewed-by: Ming Lei 
Acked-by: Tejun Heo 
Link: https://lore.kernel.org/r/20240515143059.276677-1-longman@redhat.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

blk-cgroup: fix list corruption from reorder of WRITE ->lqueued

2024-06-12T09:12:45+00:00

[ Upstream commit d0aac2363549e12cc79b8e285f13d5a9f42fd08e ]

__blkcg_rstat_flush() can be run anytime, especially when blk_cgroup_bio_start
is being executed.

If WRITE of `->lqueued` is re-ordered with READ of 'bisc->lnode.next' in
the loop of __blkcg_rstat_flush(), `next_bisc` can be assigned with one
stat instance being added in blk_cgroup_bio_start(), then the local
list in __blkcg_rstat_flush() could be corrupted.

Fix the issue by adding one barrier.

Cc: Tejun Heo 
Cc: Waiman Long 
Fixes: 3b8cc6298724 ("blk-cgroup: Optimize blkcg_rstat_flush()")
Signed-off-by: Ming Lei 
Link: https://lore.kernel.org/r/20240515013157.443672-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

blk-cgroup: fix list corruption from resetting io stat

2024-06-12T09:12:45+00:00

[ Upstream commit 6da6680632792709cecf2b006f2fe3ca7857e791 ]

Since commit 3b8cc6298724 ("blk-cgroup: Optimize blkcg_rstat_flush()"),
each iostat instance is added to blkcg percpu list, so blkcg_reset_stats()
can't reset the stat instance by memset(), otherwise the llist may be
corrupted.

Fix the issue by only resetting the counter part.

Cc: Tejun Heo 
Cc: Waiman Long 
Cc: Jay Shin 
Fixes: 3b8cc6298724 ("blk-cgroup: Optimize blkcg_rstat_flush()")
Signed-off-by: Ming Lei 
Acked-by: Tejun Heo 
Reviewed-by: Waiman Long 
Link: https://lore.kernel.org/r/20240515013157.443672-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: support to account io_ticks precisely

2024-06-12T09:11:35+00:00

[ Upstream commit 99dc422335d8b2bd4d105797241d3e715bae90e9 ]

Currently, io_ticks is accounted based on sampling, specifically
update_io_ticks() will always account io_ticks by 1 jiffies from
bdev_start_io_acct()/blk_account_io_start(), and the result can be
inaccurate, for example(HZ is 250):

Test script:
fio -filename=/dev/sda -bs=4k -rw=write -direct=1 -name=test -thinktime=4ms

Test result: util is about 90%, while the disk is really idle.

This behaviour is introduced by commit 5b18b5a73760 ("block: delete
part_round_stats and switch to less precise counting"), however, there
was a key point that is missed that this patch also improve performance
a lot:

Before the commit:
part_round_stats:
  if (part->stamp != now)
   stats |= 1;

  part_in_flight()
  -> there can be lots of task here in 1 jiffies.
  part_round_stats_single()
   __part_stat_add()
  part->stamp = now;

After the commit:
update_io_ticks:
  stamp = part->bd_stamp;
  if (time_after(now, stamp))
   if (try_cmpxchg())
    __part_stat_add()
    -> only one task can reach here in 1 jiffies.

Hence in order to account io_ticks precisely, we only need to know if
there are IO inflight at most once in one jiffies. Noted that for
rq-based device, iterating tags should not be used here because
'tags->lock' is grabbed in blk_mq_find_and_get_req(), hence
part_stat_lock_inc/dec() and part_in_flight() is used to trace inflight.
The additional overhead is quite little:

 - per cpu add/dec for each IO for rq-based device;
 - per cpu sum for each jiffies;

And it's verified by null-blk that there are no performance degration
under heavy IO pressure.

Fixes: 5b18b5a73760 ("block: delete part_round_stats and switch to less precise counting")
Signed-off-by: Yu Kuai 
Link: https://lore.kernel.org/r/20240509123717.3223892-2-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: fix and simplify blkdevparts= cmdline parsing

2024-06-12T09:11:35+00:00

[ Upstream commit bc2e07dfd2c49aaa4b52302cf7b55cf94e025f79 ]

Fix the cmdline parsing of the "blkdevparts=" parameter using strsep(),
which makes the code simpler.

Before commit 146afeb235cc ("block: use strscpy() to instead of
strncpy()"), we used a strncpy() to copy a block device name and partition
names. The commit simply replaced a strncpy() and NULL termination with
a strscpy(). It did not update calculations of length passed to strscpy().
While the length passed to strncpy() is just a length of valid characters
without NULL termination ('\0'), strscpy() takes it as a length of the
destination buffer, including a NULL termination.

Since the source buffer is not necessarily NULL terminated, the current
code copies "length - 1" characters and puts a NULL character in the
destination buffer. It replaces the last character with NULL and breaks
the parsing.

As an example, that buffer will be passed to parse_parts() and breaks
parsing sub-partitions due to the missing ')' at the end, like the
following.

example (Check Point V-80 & OpenWrt):

- Linux Kernel 6.6

  [    0.000000] Kernel command line: console=ttyS0,115200 earlycon=uart8250,mmio32,0xf0512000 crashkernel=30M mvpp2x.queue_mode=1 blkdevparts=mmcblk1:48M@10M(kernel-1),1M(dtb-1),720M(rootfs-1),48M(kernel-2),1M(dtb-2),720M(rootfs-2),300M(default_sw),650M(logs),1M(preset_cfg),1M(adsl),-(storage) maxcpus=4
  ...
  [    0.884016] mmc1: new HS200 MMC card at address 0001
  [    0.889951] mmcblk1: mmc1:0001 004GA0 3.69 GiB
  [    0.895043] cmdline partition format is invalid.
  [    0.895704]  mmcblk1: p1
  [    0.903447] mmcblk1boot0: mmc1:0001 004GA0 2.00 MiB
  [    0.908667] mmcblk1boot1: mmc1:0001 004GA0 2.00 MiB
  [    0.913765] mmcblk1rpmb: mmc1:0001 004GA0 512 KiB, chardev (248:0)

  1. "48M@10M(kernel-1),..." is passed to strscpy() with length=17
     from parse_parts()
  2. strscpy() returns -E2BIG and the destination buffer has
     "48M@10M(kernel-1\0"
  3. "48M@10M(kernel-1\0" is passed to parse_subpart()
  4. parse_subpart() fails to find ')' when parsing a partition name,
     and returns error

- Linux Kernel 6.1

  [    0.000000] Kernel command line: console=ttyS0,115200 earlycon=uart8250,mmio32,0xf0512000 crashkernel=30M mvpp2x.queue_mode=1 blkdevparts=mmcblk1:48M@10M(kernel-1),1M(dtb-1),720M(rootfs-1),48M(kernel-2),1M(dtb-2),720M(rootfs-2),300M(default_sw),650M(logs),1M(preset_cfg),1M(adsl),-(storage) maxcpus=4
  ...
  [    0.953142] mmc1: new HS200 MMC card at address 0001
  [    0.959114] mmcblk1: mmc1:0001 004GA0 3.69 GiB
  [    0.964259]  mmcblk1: p1(kernel-1) p2(dtb-1) p3(rootfs-1) p4(kernel-2) p5(dtb-2) 6(rootfs-2) p7(default_sw) p8(logs) p9(preset_cfg) p10(adsl) p11(storage)
  [    0.979174] mmcblk1boot0: mmc1:0001 004GA0 2.00 MiB
  [    0.984674] mmcblk1boot1: mmc1:0001 004GA0 2.00 MiB
  [    0.989926] mmcblk1rpmb: mmc1:0001 004GA0 512 KiB, chardev (248:0

By the way, strscpy() takes a length of destination buffer and it is
often confusing when copying characters with a specified length. Using
strsep() helps to separate the string by the specified character. Then,
we can use strscpy() naturally with the size of the destination buffer.

Separating the string on the fly is also useful to omit the redundant
string copy, reducing memory usage and improve the code readability.

Fixes: 146afeb235cc ("block: use strscpy() to instead of strncpy()")
Suggested-by: Naohiro Aota 
Signed-off-by: INAGAKI Hiroshi 
Reviewed-by: Daniel Golle 
Link: https://lore.kernel.org/r/20240421074005.565-1-musashino.open@gmail.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: refine the EOF check in blkdev_iomap_begin

2024-06-12T09:11:35+00:00

[ Upstream commit 0c12028aec837f5a002009bbf68d179d506510e8 ]

blkdev_iomap_begin rounds down the offset to the logical block size
before stashing it in iomap->offset and checking that it still is
inside the inode size.

Check the i_size check to the raw pos value so that we don't try a
zero size write if iter->pos is unaligned.

Fixes: 487c607df790 ("block: use iomap for writes to block devices")
Reported-by: syzbot+0a3683a0a6fecf909244@syzkaller.appspotmail.com
Signed-off-by: Christoph Hellwig 
Tested-by: syzbot+0a3683a0a6fecf909244@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20240503081042.2078062-1-hch@lst.de
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: add a partscan sysfs attribute for disks

2024-05-25T14:22:55+00:00

commit a4217c6740dc64a3eb6815868a9260825e8c68c6 upstream.

Userspace had been unknowingly relying on a non-stable interface of
kernel internals to determine if partition scanning is enabled for a
given disk. Provide a stable interface for this purpose instead.

Cc: stable@vger.kernel.org # 6.3+
Depends-on: 140ce28dd3be ("block: add a disk_has_partscan helper")
Signed-off-by: Christoph Hellwig 
Link: https://lore.kernel.org/linux-block/ZhQJf8mzq_wipkBH@gardel-login/
Link: https://lore.kernel.org/r/20240502130033.1958492-3-hch@lst.de
[axboe: add links and commit message from Keith]
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman