diff options
| author | Dylan Yudaken <dylany@fb.com> | 2022-08-16 06:59:59 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-10-21 12:38:47 +0200 |
| commit | ecc1e2aab59fc6ab3515397245625fb965058d30 (patch) | |
| tree | fa6674226f205aa14af79262aa0efb52f779032f /include | |
| parent | 5d80e4c0bbb03af05b60733352fa1b77f366139a (diff) | |
eventfd: guard wake_up in eventfd fs calls as well
[ Upstream commit 9f0deaa12d832f488500a5afe9b912e9b3cfc432 ]
Guard wakeups that the user can trigger, and that may end up triggering a
call back into eventfd_signal. This is in addition to the current approach
that only guards in eventfd_signal.
Rename in_eventfd_signal -> in_eventfd at the same time to reflect this.
Without this there would be a deadlock in the following code using libaio:
int main()
{
struct io_context *ctx = NULL;
struct iocb iocb;
struct iocb *iocbs[] = { &iocb };
int evfd;
uint64_t val = 1;
evfd = eventfd(0, EFD_CLOEXEC);
assert(!io_setup(2, &ctx));
io_prep_poll(&iocb, evfd, POLLIN);
io_set_eventfd(&iocb, evfd);
assert(1 == io_submit(ctx, 1, iocbs));
write(evfd, &val, 8);
}
Signed-off-by: Dylan Yudaken <dylany@fb.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20220816135959.1490641-1-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/eventfd.h | 2 | ||||
| -rw-r--r-- | include/linux/sched.h | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h index 305d5f19093b..30eb30d6909b 100644 --- a/include/linux/eventfd.h +++ b/include/linux/eventfd.h @@ -46,7 +46,7 @@ void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt); static inline bool eventfd_signal_allowed(void) { - return !current->in_eventfd_signal; + return !current->in_eventfd; } #else /* CONFIG_EVENTFD */ diff --git a/include/linux/sched.h b/include/linux/sched.h index e7b2f8a5c711..8d82d6d32670 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -936,7 +936,7 @@ struct task_struct { #endif #ifdef CONFIG_EVENTFD /* Recursion prevention for eventfd_signal() */ - unsigned in_eventfd_signal:1; + unsigned in_eventfd:1; #endif #ifdef CONFIG_IOMMU_SVA unsigned pasid_activated:1; |