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Filename Latest commit message Latest commit date
Mike Rapoport 7845532adb arm[64]/memremap: don't abuse pfn_valid() to ensure presence of linear map
commit 260364d112bc822005224667c0c9b1b17a53eafd upstream.

The semantics of pfn_valid() is to check presence of the memory map for a
PFN and not whether a PFN is covered by the linear map.  The memory map
may be present for NOMAP memory regions, but they won't be mapped in the
linear mapping.  Accessing such regions via __va() when they are
memremap()'ed will cause a crash.

On v5.4.y the crash happens on qemu-arm with UEFI [1]:

<1>[    0.084476] 8<--- cut here ---
<1>[    0.084595] Unable to handle kernel paging request at virtual address dfb76000
<1>[    0.084938] pgd = (ptrval)
<1>[    0.085038] [dfb76000] *pgd=5f7fe801, *pte=00000000, *ppte=00000000

...

<4>[    0.093923] [<c0ed6ce8>] (memcpy) from [<c16a06f8>] (dmi_setup+0x60/0x418)
<4>[    0.094204] [<c16a06f8>] (dmi_setup) from [<c16a38d4>] (arm_dmi_init+0x8/0x10)
<4>[    0.094408] [<c16a38d4>] (arm_dmi_init) from [<c0302e9c>] (do_one_initcall+0x50/0x228)
<4>[    0.094619] [<c0302e9c>] (do_one_initcall) from [<c16011e4>] (kernel_init_freeable+0x15c/0x1f8)
<4>[    0.094841] [<c16011e4>] (kernel_init_freeable) from [<c0f028cc>] (kernel_init+0x8/0x10c)
<4>[    0.095057] [<c0f028cc>] (kernel_init) from [<c03010e8>] (ret_from_fork+0x14/0x2c)

On kernels v5.10.y and newer the same crash won't reproduce on ARM because
commit b10d6bca8720 ("arch, drivers: replace for_each_membock() with
for_each_mem_range()") changed the way memory regions are registered in
the resource tree, but that merely covers up the problem.

On ARM64 memory resources registered in yet another way and there the
issue of wrong usage of pfn_valid() to ensure availability of the linear
map is also covered.

Implement arch_memremap_can_ram_remap() on ARM and ARM64 to prevent access
to NOMAP regions via the linear mapping in memremap().

Link: https://lore.kernel.org/all/Yl65zxGgFzF1Okac@sirena.org.uk
Link: https://lkml.kernel.org/r/20220426060107.7618-1-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reported-by: "kernelci.org bot" <bot@kernelci.org>
Tested-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Will Deacon <will@kernel.org>
Cc: <stable@vger.kernel.org>	[5.4+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-05-18 09:47:28 +02:00
arch arm[64]/memremap: don't abuse pfn_valid() to ensure presence of linear map 2022-05-18 09:47:28 +02:00
block block-map: add __GFP_ZERO flag for alloc_page in function bio_copy_kern 2022-05-12 12:23:48 +02:00
certs
crypto
Documentation arm: remove CONFIG_ARCH_HAS_HOLES_MEMORYMODEL 2022-05-15 19:54:46 +02:00
drivers net: phy: Fix race condition on link status change 2022-05-18 09:47:28 +02:00
fs gfs2: Fix filesystem block deallocation for short writes 2022-05-18 09:47:26 +02:00
include net/sched: act_pedit: really ensure the skb is writable 2022-05-18 09:47:25 +02:00
init init/main.c: return 1 from handled __setup() functions 2022-04-15 14:18:35 +02:00
ipc
kernel cgroup/cpuset: Remove cpus_allowed/mems_allowed setup in cpuset_init_smp() 2022-05-18 09:47:27 +02:00
lib dim: initialize all struct fields 2022-05-18 09:47:25 +02:00
LICENSES
mm mm: userfaultfd: fix missing cache flush in mcopy_atomic_pte() and __mcopy_atomic() 2022-05-15 19:54:47 +02:00
net tcp: resalt the secret every 10 seconds 2022-05-18 09:47:26 +02:00
samples
scripts gcc-plugins: latent_entropy: use /dev/urandom 2022-04-20 09:19:38 +02:00
security
sound ASoC: ops: Validate input values in snd_soc_put_volsw_range() 2022-05-18 09:47:26 +02:00
tools x86: xen: insn: Decode Xen and KVM emulate-prefix signature 2022-05-15 19:54:47 +02:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.194 2022-05-15 19:54:48 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.