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  1. 08 Oct, 2020 2 commits
    • David Howells's avatar
      afs: Fix deadlock between writeback and truncate · ec0fa0b6
      David Howells authored 
      The afs filesystem has a lock[*] that it uses to serialise I/O operations
going to the server (vnode->io_lock), as the server will only perform one
modification operation at a time on any given file or directory.  This
prevents the the filesystem from filling up all the call slots to a server
with calls that aren't going to be executed in parallel anyway, thereby
allowing operations on other files to obtain slots.

  [*] Note that is probably redundant for directories at least since
      i_rwsem is used to serialise directory modifications and
      lookup/reading vs modification.  The server does allow parallel
      non-modification ops, however.

When a file truncation op completes, we truncate the in-memory copy of the
file to match - but we do it whilst still holding the io_lock, the idea
being to prevent races with other operations.

However, if writeback starts in a worker thread simultaneously with
truncation (whilst notify_change() is called with i_rwsem locked, writeback
pays it no heed), it may manage to set PG_writeback bits on the pages that
will get truncated before afs_setattr_success() manages to call
truncate_pagecache().  Truncate will then wait for those pages - whilst
still inside io_lock:

    # cat /proc/8837/stack
    [<0>] wait_on_page_bit_common+0x184/0x1e7
    [<0>] truncate_inode_pages_range+0x37f/0x3eb
    [<0>] truncate_pagecache+0x3c/0x53
    [<0>] afs_setattr_success+0x4d/0x6e
    [<0>] afs_wait_for_operation+0xd8/0x169
    [<0>] afs_do_sync_operation+0x16/0x1f
    [<0>] afs_setattr+0x1fb/0x25d
    [<0>] notify_change+0x2cf/0x3c4
    [<0>] do_truncate+0x7f/0xb2
    [<0>] do_sys_ftruncate+0xd1/0x104
    [<0>] do_syscall_64+0x2d/0x3a
    [<0>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

The writeback operation, however, stalls indefinitely because it needs to
get the io_lock to proceed:

    # cat /proc/5940/stack
    [<0>] afs_get_io_locks+0x58/0x1ae
    [<0>] afs_begin_vnode_operation+0xc7/0xd1
    [<0>] afs_store_data+0x1b2/0x2a3
    [<0>] afs_write_back_from_locked_page+0x418/0x57c
    [<0>] afs_writepages_region+0x196/0x224
    [<0>] afs_writepages+0x74/0x156
    [<0>] do_writepages+0x2d/0x56
    [<0>] __writeback_single_inode+0x84/0x207
    [<0>] writeback_sb_inodes+0x238/0x3cf
    [<0>] __writeback_inodes_wb+0x68/0x9f
    [<0>] wb_writeback+0x145/0x26c
    [<0>] wb_do_writeback+0x16a/0x194
    [<0>] wb_workfn+0x74/0x177
    [<0>] process_one_work+0x174/0x264
    [<0>] worker_thread+0x117/0x1b9
    [<0>] kthread+0xec/0xf1
    [<0>] ret_from_fork+0x1f/0x30

and thus deadlock has occurred.

Note that whilst afs_setattr() calls filemap_write_and_wait(), the fact
that the caller is holding i_rwsem doesn't preclude more pages being
dirtied through an mmap'd region.

Fix this by:

 (1) Use the vnode validate_lock to mediate access between afs_setattr()
     and afs_writepages():

     (a) Exclusively lock validate_lock in afs_setattr() around the whole
     	 RPC operation.

     (b) If WB_SYNC_ALL isn't set on entry to afs_writepages(), trying to
     	 shared-lock validate_lock and returning immediately if we couldn't
     	 get it.

     (c) If WB_SYNC_ALL is set, wait for the lock.

     The validate_lock is also used to validate a file and to zap its cache
     if the file was altered by a third party, so it's probably a good fit
     for this.

 (2) Move the truncation outside of the io_lock in setattr, using the same
     hook as is used for local directory editing.

     This requires the old i_size to be retained in the operation record as
     we commit the revised status to the inode members inside the io_lock
     still, but we still need to know if we reduced the file size.

Fixes: d2ddc776 ("afs: Overhaul volume and server record caching and fileserver rotation")
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ec0fa0b6
    • Linus Torvalds's avatar
      mm: avoid early COW write protect games during fork() · f3c64eda
      Linus Torvalds authored 
      In commit 70e806e4 ("mm: Do early cow for pinned pages during fork()
for ptes") we write-protected the PTE before doing the page pinning
check, in order to avoid a race with concurrent fast-GUP pinning (which
doesn't take the mm semaphore or the page table lock).

That trick doesn't actually work - it doesn't handle memory ordering
properly, and doing so would be prohibitively expensive.

It also isn't really needed.  While we're moving in the direction of
allowing and supporting page pinning without marking the pinned area
with MADV_DONTFORK, the fact is that we've never really supported this
kind of odd "concurrent fork() and page pinning", and doing the
serialization on a pte level is just wrong.

We can add serialization with a per-mm sequence counter, so we know how
to solve that race properly, but we'll do that at a more appropriate
time.  Right now this just removes the write protect games.

It also turns out that the write protect games actually break on Power,
as reported by Aneesh Kumar:

 "Architecture like ppc64 expects set_pte_at to be not used for updating
  a valid pte. This is further explained in commit 56eecdb9 ("mm:
  Use ptep/pmdp_set_numa() for updating _PAGE_NUMA bit")"

and the code triggered a warning there:

  WARNING: CPU: 0 PID: 30613 at arch/powerpc/mm/pgtable.c:185 set_pte_at+0x2a8/0x3a0 arch/powerpc/mm/pgtable.c:185
  Call Trace:
    copy_present_page mm/memory.c:857 [inline]
    copy_present_pte mm/memory.c:899 [inline]
    copy_pte_range mm/memory.c:1014 [inline]
    copy_pmd_range mm/memory.c:1092 [inline]
    copy_pud_range mm/memory.c:1127 [inline]
    copy_p4d_range mm/memory.c:1150 [inline]
    copy_page_range+0x1f6c/0x2cc0 mm/memory.c:1212
    dup_mmap kernel/fork.c:592 [inline]
    dup_mm+0x77c/0xab0 kernel/fork.c:1355
    copy_mm kernel/fork.c:1411 [inline]
    copy_process+0x1f00/0x2740 kernel/fork.c:2070
    _do_fork+0xc4/0x10b0 kernel/fork.c:2429

Link: https://lore.kernel.org/lkml/CAHk-=wiWr+gO0Ro4LvnJBMs90OiePNyrE3E+pJvc9PzdBShdmw@mail.gmail.com/
Link: https://lore.kernel.org/linuxppc-dev/20201008092541.398079-1-aneesh.kumar@linux.ibm.com/Reported-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Tested-by: default avatarLeon Romanovsky <leonro@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Kirill Shutemov <kirill@shutemov.name>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f3c64eda
  3. 06 Oct, 2020 8 commits
  5. 05 Oct, 2020 3 commits
    • Linus Torvalds's avatar
      Merge tag 'platform-drivers-x86-v5.9-2' of git://git.infradead.org/linux-platform-drivers-x86 · 7575fdda
      Linus Torvalds authored 
      Pull x86 platform driver fixes from Andy Shevchenko:
 "We have some fixes for Tablet Mode reporting in particular, that users
  are complaining a lot about.

  Summary:

   - Attempt #3 of enabling Tablet Mode reporting w/o regressions

   - Improve battery recognition code in ASUS WMI driver

   - Fix Kconfig dependency warning for Fujitsu and LG laptop drivers

   - Add fixes in Thinkpad ACPI driver for _BCL method and NVRAM polling

   - Fix power supply extended topology in Mellanox driver

   - Fix memory leak in OLPC EC driver

   - Avoid static struct device in Intel PMC core driver

   - Add support for the touchscreen found in MPMAN Converter9 2-in-1

   - Update MAINTAINERS to reflect the real state of affairs"

* tag 'platform-drivers-x86-v5.9-2' of git://git.infradead.org/linux-platform-drivers-x86:
  platform/x86: thinkpad_acpi: re-initialize ACPI buffer size when reuse
  MAINTAINERS: Add Mark Gross and Hans de Goede as x86 platform drivers maintainers
  platform/x86: intel-vbtn: Switch to an allow-list for SW_TABLET_MODE reporting
  platform/x86: intel-vbtn: Revert "Fix SW_TABLET_MODE always reporting 1 on the HP Pavilion 11 x360"
  platform/x86: intel_pmc_core: do not create a static struct device
  platform/x86: mlx-platform: Fix extended topology configuration for power supply units
  platform/x86: pcengines-apuv2: Fix typo on define of AMD_FCH_GPIO_REG_GPIO55_DEVSLP0
  platform/x86: fix kconfig dependency warning for FUJITSU_LAPTOP
  platform/x86: fix kconfig dependency warning for LG_LAPTOP
  platform/x86: thinkpad_acpi: initialize tp_nvram_state variable
  platform/x86: intel-vbtn: Fix SW_TABLET_MODE always reporting 1 on the HP Pavilion 11 x360
  platform/x86: asus-wmi: Add BATC battery name to the list of supported
  platform/x86: asus-nb-wmi: Revert "Do not load on Asus T100TA and T200TA"
  platform/x86: touchscreen_dmi: Add info for the MPMAN Converter9 2-in-1
  Documentation: laptops: thinkpad-acpi: fix underline length build warning
  Platform: OLPC: Fix memleak in olpc_ec_probe
      7575fdda
    • Linus Torvalds's avatar
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net · 165563c0
      Linus Torvalds authored 
      Pull networking fixes from David Miller:

 1) Make sure SKB control block is in the proper state during IPSEC
    ESP-in-TCP encapsulation. From Sabrina Dubroca.

 2) Various kinds of attributes were not being cloned properly when we
    build new xfrm_state objects from existing ones. Fix from Antony
    Antony.

 3) Make sure to keep BTF sections, from Tony Ambardar.

 4) TX DMA channels need proper locking in lantiq driver, from Hauke
    Mehrtens.

 5) Honour route MTU during forwarding, always. From Maciej
    Żenczykowski.

 6) Fix races in kTLS which can result in crashes, from Rohit
    Maheshwari.

 7) Skip TCP DSACKs with rediculous sequence ranges, from Priyaranjan
    Jha.

 8) Use correct address family in xfrm state lookups, from Herbert Xu.

 9) A bridge FDB flush should not clear out user managed fdb entries
    with the ext_learn flag set, from Nikolay Aleksandrov.

10) Fix nested locking of netdev address lists, from Taehee Yoo.

11) Fix handling of 32-bit DATA_FIN values in mptcp, from Mat Martineau.

12) Fix r8169 data corruptions on RTL8402 chips, from Heiner Kallweit.

13) Don't free command entries in mlx5 while comp handler could still be
    running, from Eran Ben Elisha.

14) Error flow of request_irq() in mlx5 is busted, due to an off by one
    we try to free and IRQ never allocated. From Maor Gottlieb.

15) Fix leak when dumping netlink policies, from Johannes Berg.

16) Sendpage cannot be performed when a page is a slab page, or the page
    count is < 1. Some subsystems such as nvme were doing so. Create a
    "sendpage_ok()" helper and use it as needed, from Coly Li.

17) Don't leak request socket when using syncookes with mptcp, from
    Paolo Abeni.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (111 commits)
  net/core: check length before updating Ethertype in skb_mpls_{push,pop}
  net: mvneta: fix double free of txq->buf
  net_sched: check error pointer in tcf_dump_walker()
  net: team: fix memory leak in __team_options_register
  net: typhoon: Fix a typo Typoon --> Typhoon
  net: hinic: fix DEVLINK build errors
  net: stmmac: Modify configuration method of EEE timers
  tcp: fix syn cookied MPTCP request socket leak
  libceph: use sendpage_ok() in ceph_tcp_sendpage()
  scsi: libiscsi: use sendpage_ok() in iscsi_tcp_segment_map()
  drbd: code cleanup by using sendpage_ok() to check page for kernel_sendpage()
  tcp: use sendpage_ok() to detect misused .sendpage
  nvme-tcp: check page by sendpage_ok() before calling kernel_sendpage()
  net: add WARN_ONCE in kernel_sendpage() for improper zero-copy send
  net: introduce helper sendpage_ok() in include/linux/net.h
  net: usb: pegasus: Proper error handing when setting pegasus' MAC address
  net: core: document two new elements of struct net_device
  netlink: fix policy dump leak
  net/mlx5e: Fix race condition on nhe->n pointer in neigh update
  net/mlx5e: Fix VLAN create flow
  ...
      165563c0
    • Aaron Ma's avatar
      platform/x86: thinkpad_acpi: re-initialize ACPI buffer size when reuse · 720ef73d
      Aaron Ma authored 
      Evaluating ACPI _BCL could fail, then ACPI buffer size will be set to 0.
When reuse this ACPI buffer, AE_BUFFER_OVERFLOW will be triggered.

Re-initialize buffer size will make ACPI evaluate successfully.

Fixes: 46445b6b ("thinkpad-acpi: fix handle locate for video and query of _BCL")
Signed-off-by: default avatarAaron Ma <aaron.ma@canonical.com>
Signed-off-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
      720ef73d
  7. 04 Oct, 2020 6 commits
  9. 03 Oct, 2020 12 commits
  11. 02 Oct, 2020 9 commits
    • David S. Miller's avatar
      Merge tag 'mlx5-fixes-2020-09-30' of git://git.kernel.org/pub/scm/linux/kernel/git/saeed/linux · ab0faf5f
      David S. Miller authored 
      From: Saeed Mahameed <saeedm@nvidia.com>

====================
This series introduces some fixes to mlx5 driver.

v1->v2:
 - Patch #1 Don't return while mutex is held. (Dave)

v2->v3:
 - Drop patch #1, will consider a better approach (Jakub)
 - use cpu_relax() instead of cond_resched() (Jakub)
 - while(i--) to reveres a loop (Jakub)
 - Drop old mellanox email sign-off and change the committer email
   (Jakub)

Please pull and let me know if there is any problem.

For -stable v4.15
 ('net/mlx5e: Fix VLAN cleanup flow')
 ('net/mlx5e: Fix VLAN create flow')

For -stable v4.16
 ('net/mlx5: Fix request_irqs error flow')

For -stable v5.4
 ('net/mlx5e: Add resiliency in Striding RQ mode for packets larger than MTU')
 ('net/mlx5: Avoid possible free of command entry while timeout comp handler')

For -stable v5.7
 ('net/mlx5e: Fix return status when setting unsupported FEC mode')

For -stable v5.8
 ('net/mlx5e: Fix race condition on nhe->n pointer in neigh update')
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      ab0faf5f
    • Paolo Abeni's avatar
      tcp: fix syn cookied MPTCP request socket leak · 9d8c05ad
      Paolo Abeni authored 
      If a syn-cookies request socket don't pass MPTCP-level
validation done in syn_recv_sock(), we need to release
it immediately, or it will be leaked.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/89
Fixes: 9466a1cc ("mptcp: enable JOIN requests even if cookies are in use")
Reported-and-tested-by: default avatarGeliang Tang <geliangtang@gmail.com>
Reviewed-by: default avatarMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      9d8c05ad
    • David S. Miller's avatar
      Merge branch 'Introduce-sendpage_ok-to-detect-misused-sendpage-in-network-related-drivers' · e7d4005d
      David S. Miller authored 
      Coly Li says:

====================
Introduce sendpage_ok() to detect misused sendpage in network related drivers

As Sagi Grimberg suggested, the original fix is refind to a more common
inline routine:
    static inline bool sendpage_ok(struct page *page)
    {
        return  (!PageSlab(page) && page_count(page) >= 1);
    }
If sendpage_ok() returns true, the checking page can be handled by the
concrete zero-copy sendpage method in network layer.

The v10 series has 7 patches, fixes a WARN_ONCE() usage from v9 series,
- The 1st patch in this series introduces sendpage_ok() in header file
  include/linux/net.h.
- The 2nd patch adds WARN_ONCE() for improper zero-copy send in
  kernel_sendpage().
- The 3rd patch fixes the page checking issue in nvme-over-tcp driver.
- The 4th patch adds page_count check by using sendpage_ok() in
  do_tcp_sendpages() as Eric Dumazet suggested.
- The 5th and 6th patches just replace existing open coded checks with
  the inline sendpage_ok() routine.
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      e7d4005d
    • Coly Li's avatar
      libceph: use sendpage_ok() in ceph_tcp_sendpage() · 40efc4dc
      Coly Li authored 
      In libceph, ceph_tcp_sendpage() does the following checks before handle
the page by network layer's zero copy sendpage method,
	if (page_count(page) >= 1 && !PageSlab(page))

This check is exactly what sendpage_ok() does. This patch replace the
open coded checks by sendpage_ok() as a code cleanup.
Signed-off-by: default avatarColy Li <colyli@suse.de>
Acked-by: default avatarJeff Layton <jlayton@kernel.org>
Cc: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      40efc4dc
    • Coly Li's avatar
      scsi: libiscsi: use sendpage_ok() in iscsi_tcp_segment_map() · 6aa25c73
      Coly Li authored 
      In iscsci driver, iscsi_tcp_segment_map() uses the following code to
check whether the page should or not be handled by sendpage:
    if (!recv && page_count(sg_page(sg)) >= 1 && !PageSlab(sg_page(sg)))

The "page_count(sg_page(sg)) >= 1 && !PageSlab(sg_page(sg)" part is to
make sure the page can be sent to network layer's zero copy path. This
part is exactly what sendpage_ok() does.

This patch uses  use sendpage_ok() in iscsi_tcp_segment_map() to replace
the original open coded checks.
Signed-off-by: default avatarColy Li <colyli@suse.de>
Reviewed-by: default avatarLee Duncan <lduncan@suse.com>
Acked-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Cc: Vasily Averin <vvs@virtuozzo.com>
Cc: Cong Wang <amwang@redhat.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Chris Leech <cleech@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      6aa25c73
    • Coly Li's avatar
      drbd: code cleanup by using sendpage_ok() to check page for kernel_sendpage() · fb25ebe1
      Coly Li authored 
      In _drbd_send_page() a page is checked by following code before sending
it by kernel_sendpage(),
        (page_count(page) < 1) || PageSlab(page)
If the check is true, this page won't be send by kernel_sendpage() and
handled by sock_no_sendpage().

This kind of check is exactly what macro sendpage_ok() does, which is
introduced into include/linux/net.h to solve a similar send page issue
in nvme-tcp code.

This patch uses macro sendpage_ok() to replace the open coded checks to
page type and refcount in _drbd_send_page(), as a code cleanup.
Signed-off-by: default avatarColy Li <colyli@suse.de>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      fb25ebe1
    • Coly Li's avatar
      tcp: use sendpage_ok() to detect misused .sendpage · cf83a17e
      Coly Li authored 
      commit a10674bf ("tcp: detecting the misuse of .sendpage for Slab
objects") adds the checks for Slab pages, but the pages don't have
page_count are still missing from the check.

Network layer's sendpage method is not designed to send page_count 0
pages neither, therefore both PageSlab() and page_count() should be
both checked for the sending page. This is exactly what sendpage_ok()
does.

This patch uses sendpage_ok() in do_tcp_sendpages() to detect misused
.sendpage, to make the code more robust.

Fixes: a10674bf ("tcp: detecting the misuse of .sendpage for Slab objects")
Suggested-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarColy Li <colyli@suse.de>
Cc: Vasily Averin <vvs@virtuozzo.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      cf83a17e
    • Coly Li's avatar
      nvme-tcp: check page by sendpage_ok() before calling kernel_sendpage() · 7d4194ab
      Coly Li authored 
      Currently nvme_tcp_try_send_data() doesn't use kernel_sendpage() to
send slab pages. But for pages allocated by __get_free_pages() without
__GFP_COMP, which also have refcount as 0, they are still sent by
kernel_sendpage() to remote end, this is problematic.

The new introduced helper sendpage_ok() checks both PageSlab tag and
page_count counter, and returns true if the checking page is OK to be
sent by kernel_sendpage().

This patch fixes the page checking issue of nvme_tcp_try_send_data()
with sendpage_ok(). If sendpage_ok() returns true, send this page by
kernel_sendpage(), otherwise use sock_no_sendpage to handle this page.
Signed-off-by: default avatarColy Li <colyli@suse.de>
Cc: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Jan Kara <jack@suse.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Mikhail Skorzhinskii <mskorzhinskiy@solarflare.com>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Vlastimil Babka <vbabka@suse.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      7d4194ab
    • Coly Li's avatar
      net: add WARN_ONCE in kernel_sendpage() for improper zero-copy send · 7b62d31d
      Coly Li authored 
      If a page sent into kernel_sendpage() is a slab page or it doesn't have
ref_count, this page is improper to send by the zero copy sendpage()
method. Otherwise such page might be unexpected released in network code
path and causes impredictable panic due to kernel memory management data
structure corruption.

This path adds a WARN_ON() on the sending page before sends it into the
concrete zero-copy sendpage() method, if the page is improper for the
zero-copy sendpage() method, a warning message can be observed before
the consequential unpredictable kernel panic.

This patch does not change existing kernel_sendpage() behavior for the
improper page zero-copy send, it just provides hint warning message for
following potential panic due the kernel memory heap corruption.
Signed-off-by: default avatarColy Li <colyli@suse.de>
Cc: Cong Wang <amwang@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      7b62d31d
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