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  1. 03 Sep, 2021 4 commits
    • David Hildenbrand's avatar
      binfmt: remove in-tree usage of MAP_DENYWRITE · 4589ff7c
      David Hildenbrand authored 
      At exec time when we mmap the new executable via MAP_DENYWRITE we have it
opened via do_open_execat() and already deny_write_access()'ed the file
successfully. Once exec completes, we allow_write_acces(); however,
we set mm->exe_file in begin_new_exec() via set_mm_exe_file() and
also deny_write_access() as long as mm->exe_file remains set. We'll
effectively deny write access to our executable via mm->exe_file
until mm->exe_file is changed -- when the process is removed, on new
exec, or via sys_prctl(PR_SET_MM_MAP/EXE_FILE).

Let's remove all usage of MAP_DENYWRITE, it's no longer necessary for
mm->exe_file.

In case of an elf interpreter, we'll now only deny write access to the file
during exec. This is somewhat okay, because the interpreter behaves
(and sometime is) a shared library; all shared libraries, especially the
ones loaded directly in user space like via dlopen() won't ever be mapped
via MAP_DENYWRITE, because we ignore that from user space completely;
these shared libraries can always be modified while mapped and executed.
Let's only special-case the main executable, denying write access while
being executed by a process. This can be considered a minor user space
visible change.

While this is a cleanup, it also fixes part of a problem reported with
VM_DENYWRITE on overlayfs, as VM_DENYWRITE is effectively unused with
this patch and will be removed next:
  "Overlayfs did not honor positive i_writecount on realfile for
   VM_DENYWRITE mappings." [1]

[1] https://lore.kernel.org/r/YNHXzBgzRrZu1MrD@miu.piliscsaba.redhat.com/Reported-by: default avatarChengguang Xu <cgxu519@mykernel.net>
Acked-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
      4589ff7c
    • David Hildenbrand's avatar
      kernel/fork: always deny write access to current MM exe_file · fe69d560
      David Hildenbrand authored 
      We want to remove VM_DENYWRITE only currently only used when mapping the
executable during exec. During exec, we already deny_write_access() the
executable, however, after exec completes the VMAs mapped
with VM_DENYWRITE effectively keeps write access denied via
deny_write_access().

Let's deny write access when setting or replacing the MM exe_file. With
this change, we can remove VM_DENYWRITE for mapping executables.

Make set_mm_exe_file() return an error in case deny_write_access()
fails; note that this should never happen, because exec code does a
deny_write_access() early and keeps write access denied when calling
set_mm_exe_file. However, it makes the code easier to read and makes
set_mm_exe_file() and replace_mm_exe_file() look more similar.

This represents a minor user space visible change:
sys_prctl(PR_SET_MM_MAP/EXE_FILE) can now fail if the file is already
opened writable. Also, after sys_prctl(PR_SET_MM_MAP/EXE_FILE) the file
cannot be opened writable. Note that we can already fail with -EACCES if
the file doesn't have execute permissions.
Acked-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
      fe69d560
    • David Hildenbrand's avatar
      kernel/fork: factor out replacing the current MM exe_file · 35d7bdc8
      David Hildenbrand authored 
      Let's factor the main logic out into replace_mm_exe_file(), such that
all mm->exe_file logic is contained in kernel/fork.c.

While at it, perform some simple cleanups that are possible now that
we're simplifying the individual functions.
Acked-by: default avatarChristian Brauner <christian.brauner@ubuntu.com>
Acked-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
      35d7bdc8
    • David Hildenbrand's avatar
      binfmt: don't use MAP_DENYWRITE when loading shared libraries via uselib() · 42be8b42
      David Hildenbrand authored 
      uselib() is the legacy systemcall for loading shared libraries.
Nowadays, applications use dlopen() to load shared libraries, completely
implemented in user space via mmap().

For example, glibc uses MAP_COPY to mmap shared libraries. While this
maps to MAP_PRIVATE | MAP_DENYWRITE on Linux, Linux ignores any
MAP_DENYWRITE specification from user space in mmap.

With this change, all remaining in-tree users of MAP_DENYWRITE use it
to map an executable. We will be able to open shared libraries loaded
via uselib() writable, just as we already can via dlopen() from user
space.

This is one step into the direction of removing MAP_DENYWRITE from the
kernel. This can be considered a minor user space visible change.
Acked-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
      42be8b42
  3. 29 Aug, 2021 8 commits
  5. 28 Aug, 2021 3 commits
  7. 27 Aug, 2021 18 commits
  9. 26 Aug, 2021 7 commits
    • Marek Marczykowski-Górecki's avatar
      PCI/MSI: Skip masking MSI-X on Xen PV · 1a519dc7
      Marek Marczykowski-Górecki authored 
      When running as Xen PV guest, masking MSI-X is a responsibility of the
hypervisor. The guest has no write access to the relevant BAR at all - when
it tries to, it results in a crash like this:

    BUG: unable to handle page fault for address: ffffc9004069100c
    #PF: supervisor write access in kernel mode
    #PF: error_code(0x0003) - permissions violation
    RIP: e030:__pci_enable_msix_range.part.0+0x26b/0x5f0
     e1000e_set_interrupt_capability+0xbf/0xd0 [e1000e]
     e1000_probe+0x41f/0xdb0 [e1000e]
     local_pci_probe+0x42/0x80
    (...)

The recently introduced function msix_mask_all() does not check the global
variable pci_msi_ignore_mask which is set by XEN PV to bypass the masking
of MSI[-X] interrupts.

Add the check to make this function XEN PV compatible.

Fixes: 7d5ec3d3 ("PCI/MSI: Mask all unused MSI-X entries")
Signed-off-by: default avatarMarek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210826170342.135172-1-marmarek@invisiblethingslab.com
      1a519dc7
    • Linus Torvalds's avatar
      Merge tag 'nfsd-5.14-1' of git://linux-nfs.org/~bfields/linux · 73367f05
      Linus Torvalds authored 
      Pull nfsd fix from Bruce Fields:
 "This is a one-liner fix for a serious bug that can cause the server to
  become unresponsive to a client, so I think it's worth the last-minute
  inclusion for 5.14"

* tag 'nfsd-5.14-1' of git://linux-nfs.org/~bfields/linux:
  SUNRPC: Fix XPT_BUSY flag leakage in svc_handle_xprt()...
      73367f05
    • Linus Torvalds's avatar
      Merge tag 'net-5.14-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net · 8a2cb8bd
      Linus Torvalds authored 
      Pull networking fixes from Jakub Kicinski:
 "Networking fixes, including fixes from can and bpf.

  Closing three hw-dependent regressions. Any fixes of note are in the
  'old code' category. Nothing blocking release from our perspective.

  Current release - regressions:

   - stmmac: revert "stmmac: align RX buffers"

   - usb: asix: ax88772: move embedded PHY detection as early as
     possible

   - usb: asix: do not call phy_disconnect() for ax88178

   - Revert "net: really fix the build...", from Kalle to fix QCA6390

  Current release - new code bugs:

   - phy: mediatek: add the missing suspend/resume callbacks

  Previous releases - regressions:

   - qrtr: fix another OOB Read in qrtr_endpoint_post

   - stmmac: dwmac-rk: fix unbalanced pm_runtime_enable warnings

  Previous releases - always broken:

   - inet: use siphash in exception handling

   - ip_gre: add validation for csum_start

   - bpf: fix ringbuf helper function compatibility

   - rtnetlink: return correct error on changing device netns

   - e1000e: do not try to recover the NVM checksum on Tiger Lake"

* tag 'net-5.14-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (43 commits)
  Revert "net: really fix the build..."
  net: hns3: fix get wrong pfc_en when query PFC configuration
  net: hns3: fix GRO configuration error after reset
  net: hns3: change the method of getting cmd index in debugfs
  net: hns3: fix duplicate node in VLAN list
  net: hns3: fix speed unknown issue in bond 4
  net: hns3: add waiting time before cmdq memory is released
  net: hns3: clear hardware resource when loading driver
  net: fix NULL pointer reference in cipso_v4_doi_free
  rtnetlink: Return correct error on changing device netns
  net: dsa: hellcreek: Adjust schedule look ahead window
  net: dsa: hellcreek: Fix incorrect setting of GCL
  cxgb4: dont touch blocked freelist bitmap after free
  ipv4: use siphash instead of Jenkins in fnhe_hashfun()
  ipv6: use siphash in rt6_exception_hash()
  can: usb: esd_usb2: esd_usb2_rx_event(): fix the interchange of the CAN RX and TX error counters
  net: usb: asix: ax88772: fix boolconv.cocci warnings
  net/sched: ets: fix crash when flipping from 'strict' to 'quantum'
  qede: Fix memset corruption
  net: stmmac: fix kernel panic due to NULL pointer dereference of buf->xdp
  ...
      8a2cb8bd
    • Jens Axboe's avatar
      Revert "block/mq-deadline: Prioritize high-priority requests" · 7b05bf77
      Jens Axboe authored 
      This reverts commit fb926032.

Zhen reports that this commit slows down mq-deadline on a 128 thread
box, going from 258K IOPS to 170-180K. My testing shows that Optane
gen2 IOPS goes from 2.3M IOPS to 1.2M IOPS on a 64 thread box.

Looking in detail at the code, the main culprit here is needing to sum
percpu counters in the dispatch hot path, leading to very high CPU
utilization there. To make matters worse, the code currently needs to
sum 2 percpu counters, and it does so in the most naive way of iterating
possible CPUs _twice_.

Since we're close to release, revert this commit and we can re-do it
with regular per-priority counters instead for the 5.15 kernel.

Link: https://lore.kernel.org/linux-block/20210826144039.2143-1-thunder.leizhen@huawei.com/Reported-by: default avatarZhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      7b05bf77
    • Linus Torvalds's avatar
      Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux · 1a6d80ff
      Linus Torvalds authored 
      Pull arm64 fix from Will Deacon:
 "We received a report this week that the generic version of
  pfn_valid(), which we switched to this merge window in 16c9afc7
  ("arm64/mm: drop HAVE_ARCH_PFN_VALID"), interacts badly with
  dma_map_resource() due to the following check:

        /* Don't allow RAM to be mapped */
        if (WARN_ON_ONCE(pfn_valid(PHYS_PFN(phys_addr))))
                return DMA_MAPPING_ERROR;

  Since the ongoing saga to determine the semantics of pfn_valid() is
  unlikely to be resolved this week (does it indicate valid memory, or
  just the presence of a struct page, or whether that struct page has
  been initialised?), just revert back to our old version of pfn_valid()
  for 5.14.

  Summary:

   - Fix dma_map_resource() by reverting back to old pfn_valid() code"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  Partially revert "arm64/mm: drop HAVE_ARCH_PFN_VALID"
      1a6d80ff
    • Linus Torvalds's avatar
      Merge tag 'ceph-for-5.14-rc8' of git://github.com/ceph/ceph-client · 97d8cc20
      Linus Torvalds authored 
      Pull ceph fixes from Ilya Dryomov:
 "Two memory management fixes for the filesystem"

* tag 'ceph-for-5.14-rc8' of git://github.com/ceph/ceph-client:
  ceph: fix possible null-pointer dereference in ceph_mdsmap_decode()
  ceph: correctly handle releasing an embedded cap flush
      97d8cc20
    • Kalle Valo's avatar
      Revert "net: really fix the build..." · 9ebc2758
      Kalle Valo authored 
      This reverts commit ce78ffa3.

Wren and Nicolas reported that ath11k was failing to initialise QCA6390
Wi-Fi 6 device with error:

qcom_mhi_qrtr: probe of mhi0_IPCR failed with error -22

Commit ce78ffa3 ("net: really fix the build..."), introduced in
v5.14-rc5, caused this regression in qrtr. Most likely all ath11k
devices are broken, but I only tested QCA6390. Let's revert the broken
commit so that ath11k works again.
Reported-by: default avatarWren Turkal <wt@penguintechs.org>
Reported-by: default avatarNicolas Schichan <nschichan@freebox.fr>
Signed-off-by: default avatarKalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210826172816.24478-1-kvalo@codeaurora.orgSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      9ebc2758
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