Kuniyuki Iwashima cd720fad8b pipe: make poll_usage boolean and annotate its access ... commit f485922d8fe4e44f6d52a5bb95a603b7c65554bb upstream. Patch series "Fix data-races around epoll reported by KCSAN." This series suppresses a false positive KCSAN's message and fixes a real data-race. This patch (of 2): pipe_poll() runs locklessly and assigns 1 to poll_usage. Once poll_usage is set to 1, it never changes in other places. However, concurrent writes of a value trigger KCSAN, so let's make KCSAN happy. BUG: KCSAN: data-race in pipe_poll / pipe_poll write to 0xffff8880042f6678 of 4 bytes by task 174 on cpu 3: pipe_poll (fs/pipe.c:656) ep_item_poll.isra.0 (./include/linux/poll.h:88 fs/eventpoll.c:853) do_epoll_wait (fs/eventpoll.c:1692 fs/eventpoll.c:1806 fs/eventpoll.c:2234) __x64_sys_epoll_wait (fs/eventpoll.c:2246 fs/eventpoll.c:2241 fs/eventpoll.c:2241) do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:113) write to 0xffff8880042f6678 of 4 bytes by task 177 on cpu 1: pipe_poll (fs/pipe.c:656) ep_item_poll.isra.0 (./include/linux/poll.h:88 fs/eventpoll.c:853) do_epoll_wait (fs/eventpoll.c:1692 fs/eventpoll.c:1806 fs/eventpoll.c:2234) __x64_sys_epoll_wait (fs/eventpoll.c:2246 fs/eventpoll.c:2241 fs/eventpoll.c:2241) do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:113) Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 177 Comm: epoll_race Not tainted 5.17.0-58927-gf443e374ae13 #6 Hardware name: Red Hat KVM, BIOS 1.11.0-2.amzn2 04/01/2014 Link: https://lkml.kernel.org/r/20220322002653.33865-1-kuniyu@amazon.co.jp Link: https://lkml.kernel.org/r/20220322002653.33865-2-kuniyu@amazon.co.jp Fixes: 3b844826b6c6 ("pipe: avoid unnecessary EPOLLET wakeups under normal loads") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp> Cc: Alexander Duyck <alexander.h.duyck@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Kuniyuki Iwashima <kuni1840@gmail.com> Cc: "Soheil Hassas Yeganeh" <soheil@google.com> Cc: "Sridhar Samudrala" <sridhar.samudrala@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2022-06-06 08:42:41 +02:00
..
acpi	ACPICA: actypes.h: Expand the ACPI_ACCESS_ definitions	2022-01-27 10:54:18 +01:00
asm-generic	tlb: hugetlb: Add more sizes to tlb_remove_huge_tlb_entry	2022-04-20 09:23:22 +02:00
clocksource
crypto	random: replace custom notifier chain with standard one	2022-05-30 09:33:38 +02:00
drm
dt-bindings
keys
kunit
kvm
linux	pipe: make poll_usage boolean and annotate its access	2022-06-06 08:42:41 +02:00
math-emu
media
memory	memory: renesas-rpc-if: Fix HF/OSPI data transfer in Manual Mode	2022-05-09 09:05:02 +02:00
misc
net	secure_seq: use the 64 bits of the siphash for port offset calculation	2022-05-30 09:33:23 +02:00
pcmcia
ras
rdma
scsi	scsi: iscsi: Fix conn cleanup and stop race during iscsid restart	2022-04-20 09:23:17 +02:00
soc
sound	ALSA: pcm: Fix potential AB/BA lock with buffer_mutex and mmap_lock	2022-04-08 14:39:53 +02:00
target
trace	random: remove unused tracepoints	2022-05-30 09:33:34 +02:00
uapi	include/uapi/linux/xfrm.h: Fix XFRM_MSG_MAPPING ABI breakage	2022-05-25 09:18:02 +02:00
vdso
video
xen	xen/gnttab: fix gnttab_end_foreign_access() without page specified	2022-03-11 12:11:54 +01:00