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9 daysio_uring/poll: correctly handle io_poll_add() return value on updateJens Axboe1-2/+7
Commit 84230ad2d2afbf0c44c32967e525c0ad92e26b4e upstream. When the core of io_uring was updated to handle completions consistently and with fixed return codes, the POLL_REMOVE opcode with updates got slightly broken. If a POLL_ADD is pending and then POLL_REMOVE is used to update the events of that request, if that update causes the POLL_ADD to now trigger, then that completion is lost and a CQE is never posted. Additionally, ensure that if an update does cause an existing POLL_ADD to complete, that the completion value isn't always overwritten with -ECANCELED. For that case, whatever io_poll_add() set the value to should just be retained. Cc: stable@vger.kernel.org Fixes: 97b388d70b53 ("io_uring: handle completions in the core") Reported-by: syzbot+641eec6b7af1f62f2b99@syzkaller.appspotmail.com Tested-by: syzbot+641eec6b7af1f62f2b99@syzkaller.appspotmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
9 daysio_uring: fix filename leak in __io_openat_prep()Prithvi Tambewagh1-1/+1
commit b14fad555302a2104948feaff70503b64c80ac01 upstream. __io_openat_prep() allocates a struct filename using getname(). However, for the condition of the file being installed in the fixed file table as well as having O_CLOEXEC flag set, the function returns early. At that point, the request doesn't have REQ_F_NEED_CLEANUP flag set. Due to this, the memory for the newly allocated struct filename is not cleaned up, causing a memory leak. Fix this by setting the REQ_F_NEED_CLEANUP for the request just after the successful getname() call, so that when the request is torn down, the filename will be cleaned up, along with other resources needing cleanup. Reported-by: syzbot+00e61c43eb5e4740438f@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=00e61c43eb5e4740438f Tested-by: syzbot+00e61c43eb5e4740438f@syzkaller.appspotmail.com Cc: stable@vger.kernel.org Signed-off-by: Prithvi Tambewagh <activprithvi@gmail.com> Fixes: b9445598d8c6 ("io_uring: openat directly into fixed fd table") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-10-29io_uring: correct __must_hold annotation in io_install_fixed_fileAlok Tiwari1-1/+1
[ Upstream commit c5efc6a0b3940381d67887302ddb87a5cf623685 ] The __must_hold annotation references &req->ctx->uring_lock, but req is not in scope in io_install_fixed_file. This change updates the annotation to reference the correct ctx->uring_lock. improving code clarity. Fixes: f110ed8498af ("io_uring: split out fixed file installation and removal") Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-09-25io_uring: include dying ring in task_work "should cancel" stateJens Axboe4-6/+8
Commit 3539b1467e94336d5854ebf976d9627bfb65d6c3 upstream. When running task_work for an exiting task, rather than perform the issue retry attempt, the task_work is canceled. However, this isn't done for a ring that has been closed. This can lead to requests being successfully completed post the ring being closed, which is somewhat confusing and surprising to an application. Rather than just check the task exit state, also include the ring ref state in deciding whether or not to terminate a given request when run from task_work. Cc: stable@vger.kernel.org # 6.1+ Link: https://github.com/axboe/liburing/discussions/1459 Reported-by: Benedek Thaler <thaler@thaler.hu> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-09-25io_uring: backport io_should_terminate_tw()Jens Axboe4-5/+16
Parts of commit b6f58a3f4aa8dba424356c7a69388a81f4459300 upstream. Backport io_should_terminate_tw() helper to judge whether task_work should be run or terminated. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-08-28io_uring/net: commit partial buffers on retryJens Axboe1-6/+13
Commit 41b70df5b38bc80967d2e0ed55cc3c3896bba781 upstream. Ring provided buffers are potentially only valid within the single execution context in which they were acquired. io_uring deals with this and invalidates them on retry. But on the networking side, if MSG_WAITALL is set, or if the socket is of the streaming type and too little was processed, then it will hang on to the buffer rather than recycle or commit it. This is problematic for two reasons: 1) If someone unregisters the provided buffer ring before a later retry, then the req->buf_list will no longer be valid. 2) If multiple sockers are using the same buffer group, then multiple receives can consume the same memory. This can cause data corruption in the application, as either receive could land in the same userspace buffer. Fix this by disallowing partial retries from pinning a provided buffer across multiple executions, if ring provided buffers are used. Cc: stable@vger.kernel.org Reported-by: pt x <superman.xpt@gmail.com> Fixes: c56e022c0a27 ("io_uring: add support for user mapped provided buffer ring") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-24io_uring/poll: fix POLLERR handlingPavel Begunkov2-6/+8
commit c7cafd5b81cc07fb402e3068d134c21e60ea688c upstream. 8c8492ca64e7 ("io_uring/net: don't retry connect operation on EPOLLERR") is a little dirty hack that 1) wrongfully assumes that POLLERR equals to a failed request, which breaks all POLLERR users, e.g. all error queue recv interfaces. 2) deviates the connection request behaviour from connect(2), and 3) racy and solved at a wrong level. Nothing can be done with 2) now, and 3) is beyond the scope of the patch. At least solve 1) by moving the hack out of generic poll handling into io_connect(). Cc: stable@vger.kernel.org Fixes: 8c8492ca64e79 ("io_uring/net: don't retry connect operation on EPOLLERR") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/3dc89036388d602ebd84c28e5042e457bdfc952b.1752682444.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-17io_uring: make fallocate be hashed workFengnan Chang1-0/+1
[ Upstream commit 88a80066af1617fab444776135d840467414beb6 ] Like ftruncate and write, fallocate operations on the same file cannot be executed in parallel, so it is better to make fallocate be hashed work. Signed-off-by: Fengnan Chang <changfengnan@bytedance.com> Link: https://lore.kernel.org/r/20250623110218.61490-1-changfengnan@bytedance.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-27io_uring: fix task leak issue in io_wq_create()Penglei Jiang1-1/+3
commit 89465d923bda180299e69ee2800aab84ad0ba689 upstream. Add missing put_task_struct() in the error path Cc: stable@vger.kernel.org Fixes: 0f8baa3c9802 ("io-wq: fully initialize wqe before calling cpuhp_state_add_instance_nocalls()") Signed-off-by: Penglei Jiang <superman.xpt@gmail.com> Link: https://lore.kernel.org/r/20250615163906.2367-1-superman.xpt@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-27io_uring/kbuf: account ring io_buffer_list memoryPavel Begunkov1-1/+1
commit 475a8d30371604a6363da8e304a608a5959afc40 upstream. Follow the non-ringed pbuf struct io_buffer_list allocations and account it against the memcg. There is low chance of that being an actual problem as ring provided buffer should either pin user memory or allocate it, which is already accounted. Cc: stable@vger.kernel.org # 6.1 Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/3985218b50d341273cafff7234e1a7e6d0db9808.1747150490.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-27io_uring: account drain memory to cgroupPavel Begunkov1-1/+1
commit f979c20547e72568e3c793bc92c7522bc3166246 upstream. Account drain allocations against memcg. It's not a big problem as each such allocation is paired with a request, which is accounted, but it's nicer to follow the limits more closely. Cc: stable@vger.kernel.org # 6.1 Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/f8dfdbd755c41fd9c75d12b858af07dfba5bbb68.1746788718.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-19Revert "io_uring: ensure deferred completions are posted for multishot"Greg Kroah-Hartman1-8/+0
This reverts commit 746e7d285dcb96caa1845fbbb62b14bf4010cdfb which is commit 687b2bae0efff9b25e071737d6af5004e6e35af5 upstream. Jens writes: There's some missing dependencies that makes this not work right, I'll bring it back in a series instead. Link: https://lore.kernel.org/r/906ba919-32e6-4534-bbad-2cd18e1098ca@kernel.dk Reported-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-19io_uring/rw: fix wrong NOWAIT check in io_rw_init_file()Jens Axboe1-1/+1
Commit ae6a888a4357131c01d85f4c91fb32552dd0bf70 upstream. A previous commit improved how !FMODE_NOWAIT is dealt with, but inadvertently negated a check whilst doing so. This caused -EAGAIN to be returned from reading files with O_NONBLOCK set. Fix up the check for REQ_F_SUPPORT_NOWAIT. Reported-by: Julian Orth <ju.orth@gmail.com> Link: https://github.com/axboe/liburing/issues/1270 Fixes: f7c913438533 ("io_uring/rw: allow pollable non-blocking attempts for !FMODE_NOWAIT") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-19io_uring/rw: allow pollable non-blocking attempts for !FMODE_NOWAITJens Axboe1-6/+16
Commit f7c9134385331c5ef36252895130aa01a92de907 upstream. The checking for whether or not io_uring can do a non-blocking read or write attempt is gated on FMODE_NOWAIT. However, if the file is pollable, it's feasible to just check if it's currently in a state in which it can sanely receive or send _some_ data. This avoids unnecessary io-wq punts, and repeated worthless retries before doing that punt, by assuming that some data can get delivered or received if poll tells us that is true. It also allows multishot reads to properly work with these types of files, enabling a bit of a cleanup of the logic that: c9d952b9103b ("io_uring/rw: fix cflags posting for single issue multishot read") had to put in place. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-19io_uring: add io_file_can_poll() helperJens Axboe5-6/+17
Commit 95041b93e90a06bb613ec4bef9cd4d61570f68e4 upstream. This adds a flag to avoid dipping dereferencing file and then f_op to figure out if the file has a poll handler defined or not. We generally call this at least twice for networked workloads, and if using ring provided buffers, we do it on every buffer selection. Particularly the latter is troublesome, as it's otherwise a very fast operation. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-04io_uring: fix overflow resched cqe reorderingPavel Begunkov1-0/+1
[ Upstream commit a7d755ed9ce9738af3db602eb29d32774a180bc7 ] Leaving the CQ critical section in the middle of a overflow flushing can cause cqe reordering since the cache cq pointers are reset and any new cqe emitters that might get called in between are not going to be forced into io_cqe_cache_refill(). Fixes: eac2ca2d682f9 ("io_uring: check if we need to reschedule during overflow flush") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/90ba817f1a458f091f355f407de1c911d2b93bbf.1747483784.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-04io_uring/fdinfo: annotate racy sq/cq head/tail readsJens Axboe1-2/+2
[ Upstream commit f024d3a8ded0d8d2129ae123d7a5305c29ca44ce ] syzbot complains about the cached sq head read, and it's totally right. But we don't need to care, it's just reading fdinfo, and reading the CQ or SQ tail/head entries are known racy in that they are just a view into that very instant and may of course be outdated by the time they are reported. Annotate both the SQ head and CQ tail read with data_race() to avoid this syzbot complaint. Link: https://lore.kernel.org/io-uring/6811f6dc.050a0220.39e3a1.0d0e.GAE@google.com/ Reported-by: syzbot+3e77fd302e99f5af9394@syzkaller.appspotmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-18io_uring: ensure deferred completions are posted for multishotJens Axboe1-0/+8
Commit 687b2bae0efff9b25e071737d6af5004e6e35af5 upstream. Multishot normally uses io_req_post_cqe() to post completions, but when stopping it, it may finish up with a deferred completion. This is fine, except if another multishot event triggers before the deferred completions get flushed. If this occurs, then CQEs may get reordered in the CQ ring, and cause confusion on the application side. When multishot posting via io_req_post_cqe(), flush any pending deferred completions first, if any. Cc: stable@vger.kernel.org # 6.1+ Reported-by: Norman Maurer <norman_maurer@apple.com> Reported-by: Christian Mazakas <christian.mazakas@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-05-18io_uring: always arm linked timeouts prior to issueJens Axboe1-37/+16
Commit b53e523261bf058ea4a518b482222e7a277b186b upstream. There are a few spots where linked timeouts are armed, and not all of them adhere to the pre-arm, attempt issue, post-arm pattern. This can be problematic if the linked request returns that it will trigger a callback later, and does so before the linked timeout is fully armed. Consolidate all the linked timeout handling into __io_issue_sqe(), rather than have it spread throughout the various issue entry points. Cc: stable@vger.kernel.org Link: https://github.com/axboe/liburing/issues/1390 Reported-by: Chase Hiltz <chase@path.net> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-05-02io_uring: always do atomic put from iowqPavel Begunkov2-1/+8
[ Upstream commit 390513642ee6763c7ada07f0a1470474986e6c1c ] io_uring always switches requests to atomic refcounting for iowq execution before there is any parallilism by setting REQ_F_REFCOUNT, and the flag is not cleared until the request completes. That should be fine as long as the compiler doesn't make up a non existing value for the flags, however KCSAN still complains when the request owner changes oter flag bits: BUG: KCSAN: data-race in io_req_task_cancel / io_wq_free_work ... read to 0xffff888117207448 of 8 bytes by task 3871 on cpu 0: req_ref_put_and_test io_uring/refs.h:22 [inline] Skip REQ_F_REFCOUNT checks for iowq, we know it's set. Reported-by: syzbot+903a2ad71fb3f1e47cf5@syzkaller.appspotmail.com Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/d880bc27fb8c3209b54641be4ff6ac02b0e5789a.1743679736.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-02io_uring: fix 'sync' handling of io_fallback_tw()Jens Axboe1-6/+7
commit edd43f4d6f50ec3de55a0c9e9df6348d1da51965 upstream. A previous commit added a 'sync' parameter to io_fallback_tw(), which if true, means the caller wants to wait on the fallback thread handling it. But the logic is somewhat messed up, ensure that ctxs are swapped and flushed appropriately. Cc: stable@vger.kernel.org Fixes: dfbe5561ae93 ("io_uring: flush offloaded and delayed task_work on exit") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-04-25io_uring/net: fix accept multishot handlingPavel Begunkov1-0/+2
Commit f6a89bf5278d6e15016a736db67043560d1b50d5 upstream. REQ_F_APOLL_MULTISHOT doesn't guarantee it's executed from the multishot context, so a multishot accept may get executed inline, fail io_req_post_cqe(), and ask the core code to kill the request with -ECANCELED by returning IOU_STOP_MULTISHOT even when a socket has been accepted and installed. Cc: stable@vger.kernel.org Fixes: 390ed29b5e425 ("io_uring: add IORING_ACCEPT_MULTISHOT for accept") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/51c6deb01feaa78b08565ca8f24843c017f5bc80.1740331076.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-04-25io_uring/kbuf: reject zero sized provided buffersJens Axboe1-0/+2
commit cf960726eb65e8d0bfecbcce6cf95f47b1ffa6cc upstream. This isn't fixing a real issue, but there's also zero point in going through group and buffer setup, when the buffers are going to be rejected once attempted to get used. Cc: stable@vger.kernel.org Reported-by: syzbot+58928048fd1416f1457c@syzkaller.appspotmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-22io_uring: fix error pbuf checkingPavel Begunkov1-1/+3
Commit bcc87d978b834c298bbdd9c52454c5d0a946e97e upstream. Syz reports a problem, which boils down to NULL vs IS_ERR inconsistent error handling in io_alloc_pbuf_ring(). KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:__io_remove_buffers+0xac/0x700 io_uring/kbuf.c:341 Call Trace: <TASK> io_put_bl io_uring/kbuf.c:378 [inline] io_destroy_buffers+0x14e/0x490 io_uring/kbuf.c:392 io_ring_ctx_free+0xa00/0x1070 io_uring/io_uring.c:2613 io_ring_exit_work+0x80f/0x8a0 io_uring/io_uring.c:2844 process_one_work kernel/workqueue.c:3231 [inline] process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312 worker_thread+0x86d/0xd40 kernel/workqueue.c:3390 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Cc: stable@vger.kernel.org Reported-by: syzbot+2074b1a3d447915c6f1c@syzkaller.appspotmail.com Fixes: 87585b05757dc ("io_uring/kbuf: use vm_insert_pages() for mmap'ed pbuf ring") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/c5f9df20560bd9830401e8e48abc029e7cfd9f5e.1721329239.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-22io_uring: use unpin_user_pages() where appropriateJens Axboe1-3/+2
Commit 18595c0a58ae29ac6a996c5b664610119b73182d upstream. There are a few cases of open-rolled loops around unpin_user_page(), use the generic helper instead. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-22io_uring/kbuf: use vm_insert_pages() for mmap'ed pbuf ringJens Axboe4-154/+46
Commit 87585b05757dc70545efb434669708d276125559 upstream. Rather than use remap_pfn_range() for this and manually free later, switch to using vm_insert_page() and have it Just Work. This requires a bit of effort on the mmap lookup side, as the ctx uring_lock isn't held, which otherwise protects buffer_lists from being torn down, and it's not safe to grab from mmap context that would introduce an ABBA deadlock between the mmap lock and the ctx uring_lock. Instead, lookup the buffer_list under RCU, as the the list is RCU freed already. Use the existing reference count to determine whether it's possible to safely grab a reference to it (eg if it's not zero already), and drop that reference when done with the mapping. If the mmap reference is the last one, the buffer_list and the associated memory can go away, since the vma insertion has references to the inserted pages at that point. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-22io_uring/kbuf: vmap pinned buffer ringJens Axboe1-24/+15
Commit e270bfd22a2a10d1cfbaddf23e79b6d0b405d21e upstream. This avoids needing to care about HIGHMEM, and it makes the buffer indexing easier as both ring provided buffer methods are now virtually mapped in a contigious fashion. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-22io_uring: unify io_pin_pages()Jens Axboe2-58/+42
Commit 1943f96b3816e0f0d3d6686374d6e1d617c8b42c upstream. Move it into io_uring.c where it belongs, and use it in there as well rather than have two implementations of this. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-22io_uring: use vmap() for ring mappingJens Axboe1-29/+9
Commit 09fc75e0c035a2cabb8caa15cec6e85159dd94f0 upstream. This is the last holdout which does odd page checking, convert it to vmap just like what is done for the non-mmap path. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-22io_uring: fix corner case forgetting to vunmapPavel Begunkov1-1/+3
Commit 43eef70e7e2ac74e7767731dd806720c7fb5e010 upstream. io_pages_unmap() is a bit tricky in trying to figure whether the pages were previously vmap'ed or not. In particular If there is juts one page it belives there is no need to vunmap. Paired io_pages_map(), however, could've failed io_mem_alloc_compound() and attempted to io_mem_alloc_single(), which does vmap, and that leads to unpaired vmap. The solution is to fail if io_mem_alloc_compound() can't allocate a single page. That's the easiest way to deal with it, and those two functions are getting removed soon, so no need to overcomplicate it. Cc: stable@vger.kernel.org Fixes: 3ab1db3c6039e ("io_uring: get rid of remap_pfn_range() for mapping rings/sqes") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/477e75a3907a2fe83249e49c0a92cd480b2c60e0.1732569842.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-22io_uring: don't attempt to mmap larger than what the user asks forJens Axboe1-2/+3
Commit 06fe9b1df1086b42718d632aa57e8f7cd1a66a21 upstream. If IORING_FEAT_SINGLE_MMAP is ignored, as can happen if an application uses an ancient liburing or does setup manually, then 3 mmap's are required to map the ring into userspace. The kernel will still have collapsed the mappings, however userspace may ask for mapping them individually. If so, then we should not use the full number of ring pages, as it may exceed the partial mapping. Doing so will yield an -EFAULT from vm_insert_pages(), as we pass in more pages than what the application asked for. Cap the number of pages to match what the application asked for, for the particular mapping operation. Reported-by: Lucas Mülling <lmulling@proton.me> Link: https://github.com/axboe/liburing/issues/1157 Fixes: 3ab1db3c6039 ("io_uring: get rid of remap_pfn_range() for mapping rings/sqes") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-22io_uring: get rid of remap_pfn_range() for mapping rings/sqesJens Axboe2-8/+134
Commit 3ab1db3c6039e02a9deb9d5091d28d559917a645 upstream. Rather than use remap_pfn_range() for this and manually free later, switch to using vm_insert_pages() and have it Just Work. If possible, allocate a single compound page that covers the range that is needed. If that works, then we can just use page_address() on that page. If we fail to get a compound page, allocate single pages and use vmap() to map them into the kernel virtual address space. This just covers the rings/sqes, the other remaining user of the mmap remap_pfn_range() user will be converted separately. Once that is done, we can kill the old alloc/free code. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-22io-wq: backoff when retrying worker creationUday Shankar1-5/+18
[ Upstream commit 13918315c5dc5a515926c8799042ea6885c2b734 ] When io_uring submission goes async for the first time on a given task, we'll try to create a worker thread to handle the submission. Creating this worker thread can fail due to various transient conditions, such as an outstanding signal in the forking thread, so we have retry logic with a limit of 3 retries. However, this retry logic appears to be too aggressive/fast - we've observed a thread blowing through the retry limit while having the same outstanding signal the whole time. Here's an excerpt of some tracing that demonstrates the issue: First, signal 26 is generated for the process. It ends up getting routed to thread 92942. 0) cbd-92284 /* signal_generate: sig=26 errno=0 code=-2 comm=psblkdASD pid=92934 grp=1 res=0 */ This causes create_io_thread in the signalled thread to fail with ERESTARTNOINTR, and thus a retry is queued. 13) task_th-92942 /* io_uring_queue_async_work: ring 000000007325c9ae, request 0000000080c96d8e, user_data 0x0, opcode URING_CMD, flags 0x8240001, normal queue, work 000000006e96dd3f */ 13) task_th-92942 io_wq_enqueue() { 13) task_th-92942 _raw_spin_lock(); 13) task_th-92942 io_wq_activate_free_worker(); 13) task_th-92942 _raw_spin_lock(); 13) task_th-92942 create_io_worker() { 13) task_th-92942 __kmalloc_cache_noprof(); 13) task_th-92942 __init_swait_queue_head(); 13) task_th-92942 kprobe_ftrace_handler() { 13) task_th-92942 get_kprobe(); 13) task_th-92942 aggr_pre_handler() { 13) task_th-92942 pre_handler_kretprobe(); 13) task_th-92942 /* create_enter: (create_io_thread+0x0/0x50) fn=0xffffffff8172c0e0 arg=0xffff888996bb69c0 node=-1 */ 13) task_th-92942 } /* aggr_pre_handler */ ... 13) task_th-92942 } /* copy_process */ 13) task_th-92942 } /* create_io_thread */ 13) task_th-92942 kretprobe_rethook_handler() { 13) task_th-92942 /* create_exit: (create_io_worker+0x8a/0x1a0 <- create_io_thread) arg1=0xfffffffffffffdff */ 13) task_th-92942 } /* kretprobe_rethook_handler */ 13) task_th-92942 queue_work_on() { ... The CPU is then handed to a kworker to process the queued retry: ------------------------------------------ 13) task_th-92942 => kworker-54154 ------------------------------------------ 13) kworker-54154 io_workqueue_create() { 13) kworker-54154 io_queue_worker_create() { 13) kworker-54154 task_work_add() { 13) kworker-54154 wake_up_state() { 13) kworker-54154 try_to_wake_up() { 13) kworker-54154 _raw_spin_lock_irqsave(); 13) kworker-54154 _raw_spin_unlock_irqrestore(); 13) kworker-54154 } /* try_to_wake_up */ 13) kworker-54154 } /* wake_up_state */ 13) kworker-54154 kick_process(); 13) kworker-54154 } /* task_work_add */ 13) kworker-54154 } /* io_queue_worker_create */ 13) kworker-54154 } /* io_workqueue_create */ And then we immediately switch back to the original task to try creating a worker again. This fails, because the original task still hasn't handled its signal. ----------------------------------------- 13) kworker-54154 => task_th-92942 ------------------------------------------ 13) task_th-92942 create_worker_cont() { 13) task_th-92942 kprobe_ftrace_handler() { 13) task_th-92942 get_kprobe(); 13) task_th-92942 aggr_pre_handler() { 13) task_th-92942 pre_handler_kretprobe(); 13) task_th-92942 /* create_enter: (create_io_thread+0x0/0x50) fn=0xffffffff8172c0e0 arg=0xffff888996bb69c0 node=-1 */ 13) task_th-92942 } /* aggr_pre_handler */ 13) task_th-92942 } /* kprobe_ftrace_handler */ 13) task_th-92942 create_io_thread() { 13) task_th-92942 copy_process() { 13) task_th-92942 task_active_pid_ns(); 13) task_th-92942 _raw_spin_lock_irq(); 13) task_th-92942 recalc_sigpending(); 13) task_th-92942 _raw_spin_lock_irq(); 13) task_th-92942 } /* copy_process */ 13) task_th-92942 } /* create_io_thread */ 13) task_th-92942 kretprobe_rethook_handler() { 13) task_th-92942 /* create_exit: (create_worker_cont+0x35/0x1b0 <- create_io_thread) arg1=0xfffffffffffffdff */ 13) task_th-92942 } /* kretprobe_rethook_handler */ 13) task_th-92942 io_worker_release(); 13) task_th-92942 queue_work_on() { 13) task_th-92942 clear_pending_if_disabled(); 13) task_th-92942 __queue_work() { 13) task_th-92942 } /* __queue_work */ 13) task_th-92942 } /* queue_work_on */ 13) task_th-92942 } /* create_worker_cont */ The pattern repeats another couple times until we blow through the retry counter, at which point we give up. All outstanding work is canceled, and the io_uring command which triggered all this is failed with ECANCELED: 13) task_th-92942 io_acct_cancel_pending_work() { ... 13) task_th-92942 /* io_uring_complete: ring 000000007325c9ae, req 0000000080c96d8e, user_data 0x0, result -125, cflags 0x0 extra1 0 extra2 0 */ Finally, the task gets around to processing its outstanding signal 26, but it's too late. 13) task_th-92942 /* signal_deliver: sig=26 errno=0 code=-2 sa_handler=59566a0 sa_flags=14000000 */ Try to address this issue by adding a small scaling delay when retrying worker creation. This should give the forking thread time to handle its signal in the above case. This isn't a particularly satisfying solution, as sufficiently paradoxical scheduling would still have us hitting the same issue, and I'm open to suggestions for something better. But this is likely to prevent this (already rare) issue from hitting in practice. Signed-off-by: Uday Shankar <ushankar@purestorage.com> Link: https://lore.kernel.org/r/20250208-wq_retry-v2-1-4f6f5041d303@purestorage.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-07io_uring/net: save msg_control for compatPavel Begunkov1-1/+3
[ Upstream commit 6ebf05189dfc6d0d597c99a6448a4d1064439a18 ] Match the compat part of io_sendmsg_copy_hdr() with its counterpart and save msg_control. Fixes: c55978024d123 ("io_uring/net: move receive multishot out of the generic msghdr path") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/2a8418821fe83d3b64350ad2b3c0303e9b732bbd.1740498502.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-27io_uring: prevent opcode speculationPavel Begunkov1-0/+2
commit 1e988c3fe1264708f4f92109203ac5b1d65de50b upstream. sqe->opcode is used for different tables, make sure we santitise it against speculations. Cc: stable@vger.kernel.org Fixes: d3656344fea03 ("io_uring: add lookup table for various opcode needs") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Li Zetao <lizetao1@huawei.com> Link: https://lore.kernel.org/r/7eddbf31c8ca0a3947f8ed98271acc2b4349c016.1739568408.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-02-21io_uring/kbuf: reallocate buf lists on upgradePavel Begunkov1-4/+11
commit 8802766324e1f5d414a81ac43365c20142e85603 upstream. IORING_REGISTER_PBUF_RING can reuse an old struct io_buffer_list if it was created for legacy selected buffer and has been emptied. It violates the requirement that most of the field should stay stable after publish. Always reallocate it instead. Cc: stable@vger.kernel.org Reported-by: Pumpkin Chang <pumpkin@devco.re> Fixes: 2fcabce2d7d34 ("io_uring: disallow mixed provided buffer group registrations") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-02-17io_uring/rw: commit provided buffer state on asyncPavel Begunkov1-0/+10
When we get -EIOCBQUEUED, we need to ensure that the buffer is consumed from the provided buffer ring, which can be done with io_kbuf_recycle() + REQ_F_PARTIAL_IO. Reported-by: Muhammad Ramdhan <ramdhan@starlabs.sg> Reported-by: Bing-Jhong Billy Jheng <billy@starlabs.sg> Reported-by: Jacob Soo <jacob.soo@starlabs.sg> Fixes: c7fb19428d67d ("io_uring: add support for ring mapped supplied buffers") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-02-17io_uring: fix io_req_prep_async with provided buffersPavel Begunkov1-1/+4
io_req_prep_async() can import provided buffers, commit the ring state by giving up on that before, it'll be reimported later if needed. Reported-by: Muhammad Ramdhan <ramdhan@starlabs.sg> Reported-by: Bing-Jhong Billy Jheng <billy@starlabs.sg> Reported-by: Jacob Soo <jacob.soo@starlabs.sg> Fixes: c7fb19428d67d ("io_uring: add support for ring mapped supplied buffers") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-02-17io_uring/net: don't retry connect operation on EPOLLERRJens Axboe2-0/+7
commit 8c8492ca64e79c6e0f433e8c9d2bcbd039ef83d0 upstream. If a socket is shutdown before the connection completes, POLLERR is set in the poll mask. However, connect ignores this as it doesn't know, and attempts the connection again. This may lead to a bogus -ETIMEDOUT result, where it should have noticed the POLLERR and just returned -ECONNRESET instead. Have the poll logic check for whether or not POLLERR is set in the mask, and if so, mark the request as failed. Then connect can appropriately fail the request rather than retry it. Reported-by: Sergey Galas <ssgalas@cloud.ru> Cc: stable@vger.kernel.org Link: https://github.com/axboe/liburing/discussions/1335 Fixes: 3fb1bd688172 ("io_uring/net: handle -EINPROGRESS correct for IORING_OP_CONNECT") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-02-17io_uring: fix multishots with selected buffersPavel Begunkov1-0/+2
commit d63b0e8a628e62ca85a0f7915230186bb92f8bb4 upstream. We do io_kbuf_recycle() when arming a poll but every iteration of a multishot can grab more buffers, which is why we need to flush the kbuf ring state before continuing with waiting. Cc: stable@vger.kernel.org Fixes: b3fdea6ecb55c ("io_uring: multishot recv") Reported-by: Muhammad Ramdhan <ramdhan@starlabs.sg> Reported-by: Bing-Jhong Billy Jheng <billy@starlabs.sg> Reported-by: Jacob Soo <jacob.soo@starlabs.sg> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/1bfc9990fe435f1fc6152ca9efeba5eb3e68339c.1738025570.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-02-08io_uring/uring_cmd: use cached cmd_op in io_uring_cmd_sock()Jens Axboe1-1/+1
[ Upstream commit d58d82bd0efd6c8edd452fc2f6c6dd052ec57cb2 ] io_uring_cmd_sock() does a normal read of cmd->sqe->cmd_op, where it really should be using a READ_ONCE() as ->sqe may still be pointing to the original SQE. Since the prep side already does this READ_ONCE() and stores it locally, use that value rather than re-read it. Fixes: 8e9fad0e70b7b ("io_uring: Add io_uring command support for sockets") Link: https://lore.kernel.org/r/20250121-uring-sockcmd-fix-v1-1-add742802a29@google.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-01-17io_uring/eventfd: ensure io_eventfd_signal() defers another RCU periodJens Axboe1-4/+9
Commit c9a40292a44e78f71258b8522655bffaf5753bdb upstream. io_eventfd_do_signal() is invoked from an RCU callback, but when dropping the reference to the io_ev_fd, it calls io_eventfd_free() directly if the refcount drops to zero. This isn't correct, as any potential freeing of the io_ev_fd should be deferred another RCU grace period. Just call io_eventfd_put() rather than open-code the dec-and-test and free, which will correctly defer it another RCU grace period. Fixes: 21a091b970cd ("io_uring: signal registered eventfd to process deferred task work") Reported-by: Jann Horn <jannh@google.com> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-01-17io_uring/timeout: fix multishot updatesPavel Begunkov1-1/+3
commit c83c846231db8b153bfcb44d552d373c34f78245 upstream. After update only the first shot of a multishot timeout request adheres to the new timeout value while all subsequent retries continue to use the old value. Don't forget to update the timeout stored in struct io_timeout_data. Cc: stable@vger.kernel.org Fixes: ea97f6c8558e8 ("io_uring: add support for multishot timeouts") Reported-by: Christian Mazakas <christian.mazakas@gmail.com> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/e6516c3304eb654ec234cfa65c88a9579861e597.1736015288.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-01-02io_uring/sqpoll: fix sqpoll error handling racesPavel Begunkov1-0/+6
commit e33ac68e5e21ec1292490dfe061e75c0dbdd3bd4 upstream. BUG: KASAN: slab-use-after-free in __lock_acquire+0x370b/0x4a10 kernel/locking/lockdep.c:5089 Call Trace: <TASK> ... _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162 class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:551 [inline] try_to_wake_up+0xb5/0x23c0 kernel/sched/core.c:4205 io_sq_thread_park+0xac/0xe0 io_uring/sqpoll.c:55 io_sq_thread_finish+0x6b/0x310 io_uring/sqpoll.c:96 io_sq_offload_create+0x162/0x11d0 io_uring/sqpoll.c:497 io_uring_create io_uring/io_uring.c:3724 [inline] io_uring_setup+0x1728/0x3230 io_uring/io_uring.c:3806 ... Kun Hu reports that the SQPOLL creating error path has UAF, which happens if io_uring_alloc_task_context() fails and then io_sq_thread() manages to run and complete before the rest of error handling code, which means io_sq_thread_finish() is looking at already killed task. Note that this is mostly theoretical, requiring fault injection on the allocation side to trigger in practice. Cc: stable@vger.kernel.org Reported-by: Kun Hu <huk23@m.fudan.edu.cn> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/0f2f1aa5729332612bd01fe0f2f385fd1f06ce7c.1735231717.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-27io_uring/rw: avoid punting to io-wq directlyPavel Begunkov3-12/+5
Commit 6e6b8c62120a22acd8cb759304e4cd2e3215d488 upstream. kiocb_done() should care to specifically redirecting requests to io-wq. Remove the hopping to tw to then queue an io-wq, return -EAGAIN and let the core code io_uring handle offloading. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Tested-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/413564e550fe23744a970e1783dfa566291b0e6f.1710799188.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> (cherry picked from commit 6e6b8c62120a22acd8cb759304e4cd2e3215d488) Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-27io_uring/rw: treat -EOPNOTSUPP for IOCB_NOWAIT like -EAGAINJens Axboe1-0/+8
Commit c0a9d496e0fece67db777bd48550376cf2960c47 upstream. Some file systems, ocfs2 in this case, will return -EOPNOTSUPP for an IOCB_NOWAIT read/write attempt. While this can be argued to be correct, the usual return value for something that requires blocking issue is -EAGAIN. A refactoring io_uring commit dropped calling kiocb_done() for negative return values, which is otherwise where we already do that transformation. To ensure we catch it in both spots, check it in __io_read() itself as well. Reported-by: Robert Sander <r.sander@heinlein-support.de> Link: https://fosstodon.org/@gurubert@mastodon.gurubert.de/113112431889638440 Cc: stable@vger.kernel.org Fixes: a08d195b586a ("io_uring/rw: split io_read() into a helper") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-27io_uring/rw: split io_read() into a helperJens Axboe1-2/+13
Commit a08d195b586a217d76b42062f88f375a3eedda4d upstream. Add __io_read() which does the grunt of the work, leaving the completion side to the new io_read(). No functional changes in this patch. Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> (cherry picked from commit a08d195b586a217d76b42062f88f375a3eedda4d) Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-27io_uring: check if iowq is killed before queuingPavel Begunkov1-1/+5
commit dbd2ca9367eb19bc5e269b8c58b0b1514ada9156 upstream. task work can be executed after the task has gone through io_uring termination, whether it's the final task_work run or the fallback path. In this case, task work will find ->io_wq being already killed and null'ed, which is a problem if it then tries to forward the request to io_queue_iowq(). Make io_queue_iowq() fail requests in this case. Note that it also checks PF_KTHREAD, because the user can first close a DEFER_TASKRUN ring and shortly after kill the task, in which case ->iowq check would race. Cc: stable@vger.kernel.org Fixes: 50c52250e2d74 ("block: implement async io_uring discard cmd") Fixes: 773af69121ecc ("io_uring: always reissue from task_work context") Reported-by: Will <willsroot@protonmail.com> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/63312b4a2c2bb67ad67b857d17a300e1d3b078e8.1734637909.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-27io_uring: Fix registered ring file refcount leakJann Horn1-0/+1
commit 12d908116f7efd34f255a482b9afc729d7a5fb78 upstream. Currently, io_uring_unreg_ringfd() (which cleans up registered rings) is only called on exit, but __io_uring_free (which frees the tctx in which the registered ring pointers are stored) is also called on execve (via begin_new_exec -> io_uring_task_cancel -> __io_uring_cancel -> io_uring_cancel_generic -> __io_uring_free). This means: A process going through execve while having registered rings will leak references to the rings' `struct file`. Fix it by zapping registered rings on execve(). This is implemented by moving the io_uring_unreg_ringfd() from io_uring_files_cancel() into its callee __io_uring_cancel(), which is called from io_uring_task_cancel() on execve. This could probably be exploited *on 32-bit kernels* by leaking 2^32 references to the same ring, because the file refcount is stored in a pointer-sized field and get_file() doesn't have protection against refcount overflow, just a WARN_ONCE(); but on 64-bit it should have no impact beyond a memory leak. Cc: stable@vger.kernel.org Fixes: e7a6c00dc77a ("io_uring: add support for registering ring file descriptors") Signed-off-by: Jann Horn <jannh@google.com> Link: https://lore.kernel.org/r/20241218-uring-reg-ring-cleanup-v1-1-8f63e999045b@google.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-14io_uring/tctx: work around xa_store() allocation error issueJens Axboe1-1/+12
[ Upstream commit 7eb75ce7527129d7f1fee6951566af409a37a1c4 ] syzbot triggered the following WARN_ON: WARNING: CPU: 0 PID: 16 at io_uring/tctx.c:51 __io_uring_free+0xfa/0x140 io_uring/tctx.c:51 which is the WARN_ON_ONCE(!xa_empty(&tctx->xa)); sanity check in __io_uring_free() when a io_uring_task is going through its final put. The syzbot test case includes injecting memory allocation failures, and it very much looks like xa_store() can fail one of its memory allocations and end up with ->head being non-NULL even though no entries exist in the xarray. Until this issue gets sorted out, work around it by attempting to iterate entries in our xarray, and WARN_ON_ONCE() if one is found. Reported-by: syzbot+cc36d44ec9f368e443d3@syzkaller.appspotmail.com Link: https://lore.kernel.org/io-uring/673c1643.050a0220.87769.0066.GAE@google.com/ Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
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