kernel.git/io_uring/io_uring.c, branch linux-6.4.y

io_uring: break out of iowq iopoll on teardown

2023-09-13T07:48:39Z

commit 45500dc4e01c167ee063f3dcc22f51ced5b2b1e9 upstream. io-wq will retry iopoll even when it failed with -EAGAIN. If that races with task exit, which sets TIF_NOTIFY_SIGNAL for all its workers, such workers might potentially infinitely spin retrying iopoll again and again and each time failing on some allocation / waiting / etc. Don't keep spinning if io-wq is dying. Fixes: 561fb04a6a225 ("io_uring: replace workqueue usage with io-wq") Cc: stable@vger.kernel.org Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring/sqpoll: fix io-wq affinity when IORING_SETUP_SQPOLL is used

2023-09-13T07:48:39Z

commit ebdfefc09c6de7897962769bd3e63a2ff443ebf5 upstream. If we setup the ring with SQPOLL, then that polling thread has its own io-wq setup. This means that if the application uses IORING_REGISTER_IOWQ_AFF to set the io-wq affinity, we should not be setting it for the invoking task, but rather the sqpoll task. Add an sqpoll helper that parks the thread and updates the affinity, and use that one if we're using SQPOLL. Fixes: fe76421d1da1 ("io_uring: allow user configurable IO thread CPU affinity") Cc: stable@vger.kernel.org # 5.10+ Link: https://github.com/axboe/liburing/discussions/884 Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring: break iopolling on signal

2023-09-13T07:48:39Z

commit dc314886cb3d0e4ab2858003e8de2917f8a3ccbd upstream. Don't keep spinning iopoll with a signal set. It'll eventually return back, e.g. by virtue of need_resched(), but it's not a nice user experience. Cc: stable@vger.kernel.org Fixes: def596e9557c9 ("io_uring: support for IO polling") Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/eeba551e82cad12af30c3220125eb6cb244cc94c.1691594339.git.asml.silence@gmail.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring: fix false positive KASAN warnings

2023-09-13T07:48:39Z

commit 569f5308e54352a12181cc0185f848024c5443e8 upstream. io_req_local_work_add() peeks into the work list, which can be executed in the meanwhile. It's completely fine without KASAN as we're in an RCU read section and it's SLAB_TYPESAFE_BY_RCU. With KASAN though it may trigger a false positive warning because internal io_uring caches are sanitised. Remove sanitisation from the io_uring request cache for now. Cc: stable@vger.kernel.org Fixes: 8751d15426a31 ("io_uring: reduce scheduling due to tw") Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/c6fbf7a82a341e66a0007c76eefd9d57f2d3ba51.1691541473.git.asml.silence@gmail.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring: fix drain stalls by invalid SQE

2023-09-13T07:48:17Z

[ Upstream commit cfdbaa3a291d6fd2cb4a1a70d74e63b4abc2f5ec ] cq_extra is protected by ->completion_lock, which io_get_sqe() misses. The bug is harmless as it doesn't happen in real life, requires invalid SQ index array and racing with submission, and only messes up the userspace, i.e. stall requests execution but will be cleaned up on ring destruction. Fixes: 15641e427070f ("io_uring: don't cache number of dropped SQEs") Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/66096d54651b1a60534bb2023f2947f09f50ef73.1691538547.git.asml.silence@gmail.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring/parisc: Adjust pgoff in io_uring mmap() for parisc

2023-08-16T16:32:17Z

commit 56675f8b9f9b15b024b8e3145fa289b004916ab7 upstream. The changes from commit 32832a407a71 ("io_uring: Fix io_uring mmap() by using architecture-provided get_unmapped_area()") to the parisc implementation of get_unmapped_area() broke glibc's locale-gen executable when running on parisc. This patch reverts those architecture-specific changes, and instead adjusts in io_uring_mmu_get_unmapped_area() the pgoff offset which is then given to parisc's get_unmapped_area() function. This is much cleaner than the previous approach, and we still will get a coherent addresss. This patch has no effect on other architectures (SHM_COLOUR is only defined on parisc), and the liburing testcase stil passes on parisc. Cc: stable@vger.kernel.org # 6.4 Signed-off-by: Helge Deller Reported-by: Christoph Biedl Fixes: 32832a407a71 ("io_uring: Fix io_uring mmap() by using architecture-provided get_unmapped_area()") Fixes: d808459b2e31 ("io_uring: Adjust mapping wrt architecture aliasing requirements") Link: https://lore.kernel.org/r/ZNEyGV0jyI8kOOfz@p100 Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring: gate iowait schedule on having pending requests

2023-08-03T08:26:10Z

commit 7b72d661f1f2f950ab8c12de7e2bc48bdac8ed69 upstream. A previous commit made all cqring waits marked as iowait, as a way to improve performance for short schedules with pending IO. However, for use cases that have a special reaper thread that does nothing but wait on events on the ring, this causes a cosmetic issue where we know have one core marked as being "busy" with 100% iowait. While this isn't a grave issue, it is confusing to users. Rather than always mark us as being in iowait, gate setting of current->in_iowait to 1 by whether or not the waiting task has pending requests. Cc: stable@vger.kernel.org Link: https://lore.kernel.org/io-uring/CAMEGJJ2RxopfNQ7GNLhr7X9=bHXKo+G5OOe0LUq=+UgLXsv1Xg@mail.gmail.com/ Link: https://bugzilla.kernel.org/show_bug.cgi?id=217699 Link: https://bugzilla.kernel.org/show_bug.cgi?id=217700 Reported-by: Oleksandr Natalenko Reported-by: Phil Elwell Tested-by: Andres Freund Fixes: 8a796565cec3 ("io_uring: Use io_schedule* in cqring wait") Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring: don't audit the capability check in io_uring_create()

2023-08-03T08:25:42Z

[ Upstream commit 6adc2272aaaf84f34b652cf77f770c6fcc4b8336 ] The check being unconditional may lead to unwanted denials reported by LSMs when a process has the capability granted by DAC, but denied by an LSM. In the case of SELinux such denials are a problem, since they can't be effectively filtered out via the policy and when not silenced, they produce noise that may hide a true problem or an attack. Since not having the capability merely means that the created io_uring context will be accounted against the current user's RLIMIT_MEMLOCK limit, we can disable auditing of denials for this check by using ns_capable_noaudit() instead of capable(). Fixes: 2b188cc1bb85 ("Add io_uring IO interface") Link: https://bugzilla.redhat.com/show_bug.cgi?id=2193317 Signed-off-by: Ondrej Mosnacek Reviewed-by: Jeff Moyer Link: https://lore.kernel.org/r/20230718115607.65652-1-omosnace@redhat.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring: Fix io_uring mmap() by using architecture-provided get_unmapped_area()

2023-07-27T06:56:31Z

commit 32832a407a7178eec3215fad9b1a3298c14b0d69 upstream. The io_uring testcase is broken on IA-64 since commit d808459b2e31 ("io_uring: Adjust mapping wrt architecture aliasing requirements"). The reason is, that this commit introduced an own architecture independend get_unmapped_area() search algorithm which finds on IA-64 a memory region which is outside of the regular memory region used for shared userspace mappings and which can't be used on that platform due to aliasing. To avoid similar problems on IA-64 and other platforms in the future, it's better to switch back to the architecture-provided get_unmapped_area() function and adjust the needed input parameters before the call. Beside fixing the issue, the function now becomes easier to understand and maintain. This patch has been successfully tested with the io_uring testcase on physical x86-64, ppc64le, IA-64 and PA-RISC machines. On PA-RISC the LTP mmmap testcases did not report any regressions. Cc: stable@vger.kernel.org # 6.4 Signed-off-by: Helge Deller Reported-by: matoro Fixes: d808459b2e31 ("io_uring: Adjust mapping wrt architecture aliasing requirements") Link: https://lore.kernel.org/r/20230721152432.196382-2-deller@gmx.de Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring: treat -EAGAIN for REQ_F_NOWAIT as final for io-wq

2023-07-27T06:56:31Z

commit a9be202269580ca611c6cebac90eaf1795497800 upstream. io-wq assumes that an issue is blocking, but it may not be if the request type has asked for a non-blocking attempt. If we get -EAGAIN for that case, then we need to treat it as a final result and not retry or arm poll for it. Cc: stable@vger.kernel.org # 5.10+ Link: https://github.com/axboe/liburing/issues/897 Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman