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Filename Latest commit message Latest commit date
Christian Brauner d25bf5a341 taskstats: fix data-race
[ Upstream commit 0b8d616fb5a8ffa307b1d3af37f55c15dae14f28 ]

When assiging and testing taskstats in taskstats_exit() there's a race
when setting up and reading sig->stats when a thread-group with more
than one thread exits:

write to 0xffff8881157bbe10 of 8 bytes by task 7951 on cpu 0:
 taskstats_tgid_alloc kernel/taskstats.c:567 [inline]
 taskstats_exit+0x6b7/0x717 kernel/taskstats.c:596
 do_exit+0x2c2/0x18e0 kernel/exit.c:864
 do_group_exit+0xb4/0x1c0 kernel/exit.c:983
 get_signal+0x2a2/0x1320 kernel/signal.c:2734
 do_signal+0x3b/0xc00 arch/x86/kernel/signal.c:815
 exit_to_usermode_loop+0x250/0x2c0 arch/x86/entry/common.c:159
 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
 do_syscall_64+0x2d7/0x2f0 arch/x86/entry/common.c:299
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8881157bbe10 of 8 bytes by task 7949 on cpu 1:
 taskstats_tgid_alloc kernel/taskstats.c:559 [inline]
 taskstats_exit+0xb2/0x717 kernel/taskstats.c:596
 do_exit+0x2c2/0x18e0 kernel/exit.c:864
 do_group_exit+0xb4/0x1c0 kernel/exit.c:983
 __do_sys_exit_group kernel/exit.c:994 [inline]
 __se_sys_exit_group kernel/exit.c:992 [inline]
 __x64_sys_exit_group+0x2e/0x30 kernel/exit.c:992
 do_syscall_64+0xcf/0x2f0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fix this by using smp_load_acquire() and smp_store_release().

Reported-by: syzbot+c5d03165a1bd1dead0c1@syzkaller.appspotmail.com
Fixes: 34ec12349c ("taskstats: cleanup ->signal->stats allocation")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Marco Elver <elver@google.com>
Reviewed-by: Will Deacon <will@kernel.org>
Reviewed-by: Andrea Parri <parri.andrea@gmail.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Link: https://lore.kernel.org/r/20191009114809.8643-1-christian.brauner@ubuntu.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-09 10:19:54 +01:00
arch s390/cpum_sf: Avoid SBD overflow condition in irq handler 2020-01-09 10:19:49 +01:00
block iocost: over-budget forced IOs should schedule async delay 2019-12-31 16:46:19 +01:00
certs
crypto
Documentation dt-bindings: Improve validation build error handling 2020-01-04 19:18:11 +01:00
drivers PCI: Add a helper to check Power Resource Requirements _PR3 existence 2020-01-09 10:19:52 +01:00
fs afs: Fix creation calls in the dynamic root to fail with EOPNOTSUPP 2020-01-09 10:19:48 +01:00
include PCI: Fix missing inline for pci_pr3_present() 2020-01-09 10:19:53 +01:00
init
ipc
kernel taskstats: fix data-race 2020-01-09 10:19:54 +01:00
lib
LICENSES
mm shmem: pin the file in shmem_fault() if mmap_sem is dropped 2020-01-09 10:19:54 +01:00
net tcp: fix data-race in tcp_recvmsg() 2020-01-09 10:19:54 +01:00
samples
scripts scripts/kallsyms: fix definitely-lost memory leak 2020-01-04 19:18:23 +01:00
security tomoyo: Don't use nifty names on sockets. 2020-01-04 19:18:42 +01:00
sound ALSA: hda - fixup for the bass speaker on Lenovo Carbon X1 7th gen 2020-01-09 10:19:53 +01:00
tools selftests: vm: add fragment CONFIG_TEST_VMALLOC 2020-01-04 19:18:31 +01:00
usr
virt KVM: arm/arm64: Properly handle faulting of device mappings 2019-12-31 16:46:24 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.8 2020-01-04 19:19:19 +01:00
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.