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Leon Romanovsky 36e8169ec9 RDMA/ucma: Protect mc during concurrent multicast leaves
Partially revert the commit mentioned in the Fixes line to make sure that
allocation and erasing multicast struct are locked.

  BUG: KASAN: use-after-free in ucma_cleanup_multicast drivers/infiniband/core/ucma.c:491 [inline]
  BUG: KASAN: use-after-free in ucma_destroy_private_ctx+0x914/0xb70 drivers/infiniband/core/ucma.c:579
  Read of size 8 at addr ffff88801bb74b00 by task syz-executor.1/25529
  CPU: 0 PID: 25529 Comm: syz-executor.1 Not tainted 5.16.0-rc7-syzkaller #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  Call Trace:
   __dump_stack lib/dump_stack.c:88 [inline]
   dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
   print_address_description.constprop.0.cold+0x8d/0x320 mm/kasan/report.c:247
   __kasan_report mm/kasan/report.c:433 [inline]
   kasan_report.cold+0x83/0xdf mm/kasan/report.c:450
   ucma_cleanup_multicast drivers/infiniband/core/ucma.c:491 [inline]
   ucma_destroy_private_ctx+0x914/0xb70 drivers/infiniband/core/ucma.c:579
   ucma_destroy_id+0x1e6/0x280 drivers/infiniband/core/ucma.c:614
   ucma_write+0x25c/0x350 drivers/infiniband/core/ucma.c:1732
   vfs_write+0x28e/0xae0 fs/read_write.c:588
   ksys_write+0x1ee/0x250 fs/read_write.c:643
   do_syscall_x64 arch/x86/entry/common.c:50 [inline]
   do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
   entry_SYSCALL_64_after_hwframe+0x44/0xae

Currently the xarray search can touch a concurrently freeing mc as the
xa_for_each() is not surrounded by any lock. Rather than hold the lock for
a full scan hold it only for the effected items, which is usually an empty
list.

Fixes: 95fe51096b ("RDMA/ucma: Remove mc_list and rely on xarray")
Link: https://lore.kernel.org/r/1cda5fabb1081e8d16e39a48d3a4f8160cea88b8.1642491047.git.leonro@nvidia.com
Reported-by: syzbot+e3f96c43d19782dd14a7@syzkaller.appspotmail.com
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Maor Gottlieb <maorg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
2022-01-28 11:36:55 -04:00
arch bitmap patches for 5.17-rc1 2022-01-23 06:20:44 +02:00
block bitmap patches for 5.17-rc1 2022-01-23 06:20:44 +02:00
certs certs: Fix build error when CONFIG_MODULE_SIG_KEY is empty 2022-01-23 00:08:44 +09:00
crypto lib/crypto: add prompts back to crypto libraries 2022-01-18 13:03:55 +01:00
Documentation Merge branch 'akpm' (patches from Andrew) 2022-01-22 11:28:23 +02:00
drivers RDMA/ucma: Protect mc during concurrent multicast leaves 2022-01-28 11:36:55 -04:00
fs bitmap patches for 5.17-rc1 2022-01-23 06:20:44 +02:00
include bitmap patches for 5.17-rc1 2022-01-23 06:20:44 +02:00
init lib/stackdepot: allow optional init and stack_table allocation by kvmalloc() 2022-01-22 08:33:37 +02:00
ipc proc: remove PDE_DATA() completely 2022-01-22 08:33:37 +02:00
kernel ftrace: Fix s390 breakage from sorting mcount tables 2022-01-23 08:07:02 +02:00
lib bitmap patches for 5.17-rc1 2022-01-23 06:20:44 +02:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm bitmap patches for 5.17-rc1 2022-01-23 06:20:44 +02:00
net bitmap patches for 5.17-rc1 2022-01-23 06:20:44 +02:00
samples Merge branch 'akpm' (patches from Andrew) 2022-01-20 10:41:01 +02:00
scripts Devicetree fixes for v5.17, take 1: 2022-01-22 09:52:17 +02:00
security fs.idmapped.v5.17 2022-01-11 14:26:55 -08:00
sound proc: remove PDE_DATA() completely 2022-01-22 08:33:37 +02:00
tools perf tools changes for v5.17: 2nd batch 2022-01-23 08:14:21 +02:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-01-22 21:48:45 +09:00
virt Generic: 2022-01-22 09:40:01 +02:00
.clang-format genirq/msi: Make interrupt allocation less convoluted 2021-12-16 22:22:20 +01:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap RISCV: 2022-01-16 16:15:14 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Removing Ohad from remoteproc/rpmsg maintenance 2021-12-08 10:09:40 -07:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS bitmap patches for 5.17-rc1 2022-01-23 06:20:44 +02:00
Makefile Linux 5.17-rc1 2022-01-23 10:12:53 +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.