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  1. 14 Feb, 2023 1 commit
    • Linus Torvalds's avatar
      Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm · 82eac0c8
      Linus Torvalds authored 
      Pull kvm fixes from Paolo Bonzini:
 "Certain AMD processors are vulnerable to a cross-thread return address
  predictions bug. When running in SMT mode and one of the sibling
  threads transitions out of C0 state, the other thread gets access to
  twice as many entries in the RSB, but unfortunately the predictions of
  the now-halted logical processor are not purged. Therefore, the
  executing processor could speculatively execute from locations that
  the now-halted processor had trained the RSB on.

  The Spectre v2 mitigations cover the Linux kernel, as it fills the RSB
  when context switching to the idle thread. However, KVM allows a VMM
  to prevent exiting guest mode when transitioning out of C0 using the
  KVM_CAP_X86_DISABLE_EXITS capability can be used by a VMM to change
  this behavior. To mitigate the cross-thread return address predictions
  bug, a VMM must not be allowed to override the default behavior to
  intercept C0 transitions.

  These patches introduce a KVM module parameter that, if set, will
  prevent the user from disabling the HLT, MWAIT and CSTATE exits"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  Documentation/hw-vuln: Add documentation for Cross-Thread Return Predictions
  KVM: x86: Mitigate the cross-thread return address predictions bug
  x86/speculation: Identify processors vulnerable to SMT RSB predictions
      82eac0c8
  3. 13 Feb, 2023 2 commits
  5. 12 Feb, 2023 10 commits
  7. 11 Feb, 2023 5 commits
  9. 10 Feb, 2023 19 commits
  11. 09 Feb, 2023 3 commits
    • Isaac J. Manjarres's avatar
      of: reserved_mem: Have kmemleak ignore dynamically allocated reserved mem · ce4d9a1e
      Isaac J. Manjarres authored 
      Patch series "Fix kmemleak crashes when scanning CMA regions", v2.

When trying to boot a device with an ARM64 kernel with the following
config options enabled:

CONFIG_DEBUG_PAGEALLOC=y
CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT=y
CONFIG_DEBUG_KMEMLEAK=y

a crash is encountered when kmemleak starts to scan the list of gray
or allocated objects that it maintains. Upon closer inspection, it was
observed that these page-faults always occurred when kmemleak attempted
to scan a CMA region.

At the moment, kmemleak is made aware of CMA regions that are specified
through the devicetree to be dynamically allocated within a range of
addresses. However, kmemleak should not need to scan CMA regions or any
reserved memory region, as those regions can be used for DMA transfers
between drivers and peripherals, and thus wouldn't contain anything
useful for kmemleak.

Additionally, since CMA regions are unmapped from the kernel's address
space when they are freed to the buddy allocator at boot when
CONFIG_DEBUG_PAGEALLOC is enabled, kmemleak shouldn't attempt to access
those memory regions, as that will trigger a crash. Thus, kmemleak
should ignore all dynamically allocated reserved memory regions.


This patch (of 1):

Currently, kmemleak ignores dynamically allocated reserved memory regions
that don't have a kernel mapping.  However, regions that do retain a
kernel mapping (e.g.  CMA regions) do get scanned by kmemleak.

This is not ideal for two reasons:

1  kmemleak works by scanning memory regions for pointers to allocated
   objects to determine if those objects have been leaked or not. 
   However, reserved memory regions can be used between drivers and
   peripherals for DMA transfers, and thus, would not contain pointers to
   allocated objects, making it unnecessary for kmemleak to scan these
   reserved memory regions.

2  When CONFIG_DEBUG_PAGEALLOC is enabled, along with kmemleak, the
   CMA reserved memory regions are unmapped from the kernel's address
   space when they are freed to buddy at boot.  These CMA reserved regions
   are still tracked by kmemleak, however, and when kmemleak attempts to
   scan them, a crash will happen, as accessing the CMA region will result
   in a page-fault, since the regions are unmapped.

Thus, use kmemleak_ignore_phys() for all dynamically allocated reserved
memory regions, instead of those that do not have a kernel mapping
associated with them.

Link: https://lkml.kernel.org/r/20230208232001.2052777-1-isaacmanjarres@google.com
Link: https://lkml.kernel.org/r/20230208232001.2052777-2-isaacmanjarres@google.com
Fixes: a7259df7 ("memblock: make memblock_find_in_range method private")
Signed-off-by: default avatarIsaac J. Manjarres <isaacmanjarres@google.com>
Acked-by: default avatarMike Rapoport (IBM) <rppt@kernel.org>
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Kirill A. Shutemov <kirill.shtuemov@linux.intel.com>
Cc: Nick Kossifidis <mick@ics.forth.gr>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Cc: Saravana Kannan <saravanak@google.com>
Cc: <stable@vger.kernel.org>	[5.15+]
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      ce4d9a1e
    • Jeff Xie's avatar
      scripts/gdb: fix 'lx-current' for x86 · c16a3b11
      Jeff Xie authored 
      When printing the name of the current process, it will report an error:
(gdb) p $lx_current().comm Python Exception <class 'gdb.error'> No symbol
"current_task" in current context.: Error occurred in Python: No symbol
"current_task" in current context.

Because e57ef2ed ("x86: Put hot per CPU variables into a struct")
changed it.

Link: https://lkml.kernel.org/r/20230204090139.1789264-1-xiehuan09@gmail.com
Fixes: e57ef2ed ("x86: Put hot per CPU variables into a struct")
Signed-off-by: default avatarJeff Xie <xiehuan09@gmail.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      c16a3b11
    • Li Lingfeng's avatar
      lib: parser: optimize match_NUMBER apis to use local array · 67222c4b
      Li Lingfeng authored 
      Memory will be allocated to store substring_t in match_strdup(), which
means the caller of match_strdup() may need to be scheduled out to wait
for reclaiming memory.  smatch complains that this can cuase sleeping in
an atoic context.

Using local array to store substring_t to remove the restriction.

Link: https://lkml.kernel.org/r/20230120032352.242767-1-lilingfeng3@huawei.com
Link: https://lore.kernel.org/all/20221104023938.2346986-5-yukuai1@huaweicloud.com/
Link: https://lkml.kernel.org/r/20230120032352.242767-1-lilingfeng3@huawei.com
Fixes: 2c064798 ("blk-iocost: don't release 'ioc->lock' while updating params")
Signed-off-by: default avatarLi Lingfeng <lilingfeng3@huawei.com>
Reported-by: default avatarYu Kuai <yukuai1@huaweicloud.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Cc: BingJing Chang <bingjingc@synology.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Hou Tao <houtao1@huawei.com>
Cc: James Smart <james.smart@broadcom.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: yangerkun <yangerkun@huawei.com>
Cc: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      67222c4b
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