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Chen Jingwen 98574c91e3 elf: don't use MAP_FIXED_NOREPLACE for elf interpreter mappings
commit 9b2f72cc0a upstream.

In commit b212921b13 ("elf: don't use MAP_FIXED_NOREPLACE for elf
executable mappings") we still leave MAP_FIXED_NOREPLACE in place for
load_elf_interp.

Unfortunately, this will cause kernel to fail to start with:

    1 (init): Uhuuh, elf segment at 00003ffff7ffd000 requested but the memory is mapped already
    Failed to execute /init (error -17)

The reason is that the elf interpreter (ld.so) has overlapping segments.

  readelf -l ld-2.31.so
  Program Headers:
    Type           Offset             VirtAddr           PhysAddr
                   FileSiz            MemSiz              Flags  Align
    LOAD           0x0000000000000000 0x0000000000000000 0x0000000000000000
                   0x000000000002c94c 0x000000000002c94c  R E    0x10000
    LOAD           0x000000000002dae0 0x000000000003dae0 0x000000000003dae0
                   0x00000000000021e8 0x0000000000002320  RW     0x10000
    LOAD           0x000000000002fe00 0x000000000003fe00 0x000000000003fe00
                   0x00000000000011ac 0x0000000000001328  RW     0x10000

The reason for this problem is the same as described in commit
ad55eac74f ("elf: enforce MAP_FIXED on overlaying elf segments").

Not only executable binaries, elf interpreters (e.g. ld.so) can have
overlapping elf segments, so we better drop MAP_FIXED_NOREPLACE and go
back to MAP_FIXED in load_elf_interp.

Fixes: 4ed2863951 ("fs, elf: drop MAP_FIXED usage from elf_map")
Cc: <stable@vger.kernel.org> # v4.19
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Chen Jingwen <chenjingwen6@huawei.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-06 15:42:35 +02:00
Documentation dt-bindings: mtd: gpmc: Fix the ECC bytes vs. OOB bytes equation 2021-09-22 12:26:43 +02:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch perf/x86/intel: Update event constraints for ICX 2021-10-06 15:42:35 +02:00
block Revert "block, bfq: honor already-setup queue merges" 2021-10-06 15:42:34 +02:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:47:29 +02:00
crypto crypto: shash - avoid comparing pointers to exported functions under CFI 2021-07-14 16:53:13 +02:00
drivers net: hns3: do not allow call hns3_nic_net_open repeatedly 2021-10-06 15:42:34 +02:00
fs elf: don't use MAP_FIXED_NOREPLACE for elf interpreter mappings 2021-10-06 15:42:35 +02:00
include af_unix: fix races in sk_peer_pid and sk_peer_cred accesses 2021-10-06 15:42:35 +02:00
init kbuild: add CONFIG_LD_IS_LLD 2021-06-30 08:47:44 -04:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel cpufreq: schedutil: Use kobject release() method to free sugov_tunables 2021-10-06 15:42:29 +02:00
lib Kconfig.debug: drop selecting non-existing HARDLOCKUP_DETECTOR_ARCH 2021-09-26 14:07:10 +02:00
mm mm/memory_hotplug: use "unsigned long" for PFN in zone_for_pfn_range() 2021-09-22 12:26:43 +02:00
net af_unix: fix races in sk_peer_pid and sk_peer_cred accesses 2021-10-06 15:42:35 +02:00
samples samples: bpf: Fix tracex7 error raised on the missing argument 2021-09-22 12:26:30 +02:00
scripts kbuild: Fix 'no symbols' warning when CONFIG_TRIM_UNUSD_KSYMS=y 2021-09-22 12:26:26 +02:00
security apparmor: remove duplicate macro list_entry_is_head() 2021-09-26 14:07:06 +02:00
sound ASoC: rockchip: i2s: Fixup config for DAIFMT_DSP_A/B 2021-09-22 12:26:35 +02:00
tools selftests, bpf: test_lwt_ip_encap: Really disable rp_filter 2021-10-06 15:42:34 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: remember position in kvm->vcpus array 2021-09-26 14:07:05 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.150 2021-09-30 10:09:26 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.