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Haren Myneni 959dc1b16e powerpc/pseries/vas: Hold mmap_mutex after mmap lock during window close 
[ Upstream commit b59c9dc4d9 ]

Commit 8ef7b9e176 ("powerpc/pseries/vas: Close windows with DLPAR
core removal") unmaps the window paste address and issues HCALL to
close window in the hypervisor for migration or DLPAR core removal
events. So holds mmap_mutex and then mmap lock before unmap the
paste address. But if the user space issue mmap paste address at
the same time with the migration event, coproc_mmap() is called
after holding the mmap lock which can trigger deadlock when trying
to acquire mmap_mutex in coproc_mmap().

t1: mmap() call to mmap              t2: Migration event
    window paste address

do_mmap2()                           migration_store()
 ksys_mmap_pgoff()                    pseries_migrate_partition()
  vm_mmap_pgoff()                      vas_migration_handler()
    Acquire mmap lock                   reconfig_close_windows()
    do_mmap()                             lock mmap_mutex
     mmap_region()                        Acquire mmap lock
      call_mmap()                         //Wait for mmap lock
       coproc_mmap()                        unmap vma
         lock mmap_mutex                    update window status
         //wait for mmap_mutex            Release mmap lock
          mmap vma                        unlock mmap_mutex
          update window status
         unlock mmap_mutex
    ...
    Release mmap lock

Fix this deadlock issue by holding mmap lock first before mmap_mutex
in reconfig_close_windows().

Fixes: 8ef7b9e176 ("powerpc/pseries/vas: Close windows with DLPAR core removal")
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230716100506.7833-1-haren@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2023-08-03 10:25:41 +02:00
arch powerpc/pseries/vas: Hold mmap_mutex after mmap lock during window close 2023-08-03 10:25:41 +02:00
block blk-mq: Fix stall due to recursive flush plug 2023-08-03 10:25:41 +02:00
certs KEYS: Add missing function documentation 2023-04-24 16:15:52 +03:00
crypto crypto: jitter - correct health test during initialization 2023-07-19 16:36:19 +02:00
Documentation media: uapi: Fix [GS]_ROUTING ACTIVE flag value 2023-07-23 13:54:08 +02:00
drivers r8169: revert 2ab19de62d ("r8169: remove ASPM restrictions now that ASPM is disabled during NAPI poll") 2023-08-03 10:25:41 +02:00
fs jbd2: Fix wrongly judgement for buffer head removing while doing checkpoint 2023-08-03 10:25:41 +02:00
include tcp: annotate data-races around fastopenq.max_qlen 2023-07-27 08:57:05 +02:00
init kbuild: Fix CFI failures with GCOV 2023-07-19 16:36:23 +02:00
io_uring io_uring: Fix io_uring mmap() by using architecture-provided get_unmapped_area() 2023-07-27 08:56:31 +02:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel tracing/histograms: Return an error if we fail to add histogram to hist_vars list 2023-07-27 08:57:06 +02:00
lib iov_iter: Mark copy_iovec_from_user() noclone 2023-07-27 08:56:53 +02:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/mlock: fix vma iterator conversion of apply_vma_lock_flags() 2023-07-27 08:56:32 +02:00
net tcp: annotate data-races around fastopenq.max_qlen 2023-07-27 08:57:05 +02:00
rust Rust changes for v6.4 2023-04-30 11:20:22 -07:00
samples samples: ftrace: Save required argument registers in sample trampolines 2023-07-23 13:54:09 +02:00
scripts kbuild: rust: avoid creating temporary files 2023-07-27 08:57:06 +02:00
security security: keys: Modify mismatched function name 2023-07-27 08:56:59 +02:00
sound ALSA: hda/realtek: Fix generic fixup definition for cs35l41 amp 2023-07-27 08:57:01 +02:00
tools perf build: Fix library not found error when using CSLIBS 2023-07-27 08:56:54 +02:00
usr initramfs: Check negative timestamp to prevent broken cpio archive 2023-04-16 17:37:01 +09:00
virt KVM: Avoid illegal stage2 mapping on invalid memory slot 2023-06-22 15:14:57 -04:00
.clang-format cxl for v6.4 2023-04-30 11:51:51 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for *.dtso files 2023-02-26 15:28:23 +09:00
.gitignore linux-kselftest-kunit-6.4-rc1 2023-04-24 12:31:32 -07:00
.mailmap mailmap: add entries for Ben Dooks 2023-06-19 13:19:35 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: sctp: move Neil to CREDITS 2023-05-12 08:51:32 +01:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Networking fixes for 6.4-rc8, including fixes from ipsec, bpf, 2023-06-22 17:59:51 -07:00
Makefile Linux 6.4.7 2023-07-27 08:57:07 +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.