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* io_uring/waitid: always remove waitid entry for cancel allJens Axboe2024-04-031-6/+1
| | | | | | | | | | | | | | | | | | [ Upstream commit 2b35b8b43e07b1a6f06fdd84cf4b9eb24785896d ] We know the request is either being removed, or already in the process of being removed through task_work, so we can delete it from our waitid list upfront. This is important for remove all conditions, as we otherwise will find it multiple times and prevent cancelation progress. Remove the dead check in cancelation as well for the hash_node being empty or not. We already have a waitid reference check for ownership, so we don't need to check the list too. Cc: stable@vger.kernel.org Fixes: f31ecf671ddc ("io_uring: add IORING_OP_WAITID support") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring/futex: always remove futex entry for cancel allJens Axboe2024-04-031-0/+1
| | | | | | | | | | | | | | | [ Upstream commit 30dab608c3cb99c2a05b76289fd05551703979ae ] We know the request is either being removed, or already in the process of being removed through task_work, so we can delete it from our futex list upfront. This is important for remove all conditions, as we otherwise will find it multiple times and prevent cancelation progress. Cc: stable@vger.kernel.org Fixes: 194bb58c6090 ("io_uring: add support for futex wake and wait") Fixes: 8f350194d5cf ("io_uring: add support for vectored futex waits") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring: clean rings on NO_MMAP alloc failPavel Begunkov2024-04-031-2/+3
| | | | | | | | | | | | | | | | [ Upstream commit cef59d1ea7170ec753182302645a0191c8aa3382 ] We make a few cancellation judgements based on ctx->rings, so let's zero it afer deallocation for IORING_SETUP_NO_MMAP just like it's done with the mmap case. Likely, it's not a real problem, but zeroing is safer and better tested. Cc: stable@vger.kernel.org Fixes: 03d89a2de25bbc ("io_uring: support for user allocated memory for rings/sqes") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/9ff6cdf91429b8a51699c210e1f6af6ea3f8bdcf.1710255382.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring/rw: return IOU_ISSUE_SKIP_COMPLETE for multishot retryJens Axboe2024-04-031-0/+2
| | | | | | | | | | | | | | | [ Upstream commit 0a3737db8479b77f95f4bfda8e71b03c697eb56a ] If read multishot is being invoked from the poll retry handler, then we should return IOU_ISSUE_SKIP_COMPLETE rather than -EAGAIN. If not, then a CQE will be posted with -EAGAIN rather than triggering the retry when the file is flagged as readable again. Cc: stable@vger.kernel.org Reported-by: Sargun Dhillon <sargun@meta.com> Fixes: fc68fcda04910 ("io_uring/rw: add support for IORING_OP_READ_MULTISHOT") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring: fix mshot io-wq checksPavel Begunkov2024-04-031-1/+1
| | | | | | | | | | | | | | | | [ Upstream commit 3a96378e22cc46c7c49b5911f6c8631527a133a9 ] When checking for concurrent CQE posting, we're not only interested in requests running from the poll handler but also strayed requests ended up in normal io-wq execution. We're disallowing multishots in general from io-wq, not only when they came in a certain way. Cc: stable@vger.kernel.org Fixes: 17add5cea2bba ("io_uring: force multishot CQEs into task context") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/d8c5b36a39258036f93301cd60d3cd295e40653d.1709905727.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring/net: correctly handle multishot recvmsg retry setupJens Axboe2024-04-031-1/+2
| | | | | | | | | | | | | | | [ Upstream commit deaef31bc1ec7966698a427da8c161930830e1cf ] If we loop for multishot receive on the initial attempt, and then abort later on to wait for more, we miss a case where we should be copying the io_async_msghdr from the stack to stable storage. This leads to the next retry potentially failing, if the application had the msghdr on the stack. Cc: stable@vger.kernel.org Fixes: 9bb66906f23e ("io_uring: support multishot in recvmsg") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring: fix io_queue_proc modifying req->flagsPavel Begunkov2024-04-031-8/+11
| | | | | | | | | | | | | | | | | [ Upstream commit 1a8ec63b2b6c91caec87d4e132b1f71b5df342be ] With multiple poll entries __io_queue_proc() might be running in parallel with poll handlers and possibly task_work, we should not be carelessly modifying req->flags there. io_poll_double_prepare() handles a similar case with locking but it's much easier to move it into __io_arm_poll_handler(). Cc: stable@vger.kernel.org Fixes: 595e52284d24a ("io_uring/poll: don't enable lazy wake for POLLEXCLUSIVE") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/455cc49e38cf32026fa1b49670be8c162c2cb583.1709834755.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring: fix mshot read defer taskrun cqe postingPavel Begunkov2024-04-031-0/+2
| | | | | | | | | | | | | | [ Upstream commit 70581dcd0601a09f134f23268e3374e15d736824 ] We can't post CQEs from io-wq with DEFER_TASKRUN set, normal completions are handled but aux should be explicitly disallowed by opcode handlers. Cc: stable@vger.kernel.org Fixes: fc68fcda04910 ("io_uring/rw: add support for IORING_OP_READ_MULTISHOT") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/6fb7cba6f5366da25f4d3eb95273f062309d97fa.1709740837.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring: fix poll_remove stalled req completionPavel Begunkov2024-03-261-2/+2
| | | | | | | | | | | | | | | [ Upstream commit 5e3afe580a9f5ca173a6bd55ffe10948796ef7e5 ] Taking the ctx lock is not enough to use the deferred request completion infrastructure, it'll get queued into the list but no one would expect it there, so it will sit there until next io_submit_flush_completions(). It's hard to care about the cancellation path, so complete it via tw. Fixes: ef7dfac51d8ed ("io_uring/poll: serialize poll linked timer start with poll removal") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/c446740bc16858f8a2a8dcdce899812f21d15f23.1710514702.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring: Fix release of pinned pages when __io_uaddr_map failsGabriel Krisman Bertazi2024-03-261-9/+13
| | | | | | | | | | | | | | | | | [ Upstream commit 67d1189d1095d471ed7fa426c7e384a7140a5dd7 ] Looking at the error path of __io_uaddr_map, if we fail after pinning the pages for any reasons, ret will be set to -EINVAL and the error handler won't properly release the pinned pages. I didn't manage to trigger it without forcing a failure, but it can happen in real life when memory is heavily fragmented. Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de> Fixes: 223ef4743164 ("io_uring: don't allow IORING_SETUP_NO_MMAP rings on highmem pages") Link: https://lore.kernel.org/r/20240313213912.1920-1-krisman@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring: don't save/restore iowait stateJens Axboe2024-03-261-3/+2
| | | | | | | | | | | | | [ Upstream commit 6f0974eccbf78baead1735722c4f1ee3eb9422cd ] This kind of state is per-syscall, and since we're doing the waiting off entering the io_uring_enter(2) syscall, there's no way that iowait can already be set for this case. Simplify it by setting it if we need to, and always clearing it to 0 when done. Fixes: 7b72d661f1f2 ("io_uring: gate iowait schedule on having pending requests") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring/net: correct the type of variableMuhammad Usama Anjum2024-03-261-1/+1
| | | | | | | | | | | | | [ Upstream commit 86bcacc957fc2d0403aa0e652757eec59a5fd7ca ] The namelen is of type int. It shouldn't be made size_t which is unsigned. The signed number is needed for error checking before use. Fixes: c55978024d12 ("io_uring/net: move receive multishot out of the generic msghdr path") Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com> Link: https://lore.kernel.org/r/20240301144349.2807544-1-usama.anjum@collabora.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring/net: fix overflow check in io_recvmsg_mshot_prep()Dan Carpenter2024-03-261-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 8ede3db5061bb1fe28e2c9683329aafa89d2b1b4 ] The "controllen" variable is type size_t (unsigned long). Casting it to int could lead to an integer underflow. The check_add_overflow() function considers the type of the destination which is type int. If we add two positive values and the result cannot fit in an integer then that's counted as an overflow. However, if we cast "controllen" to an int and it turns negative, then negative values *can* fit into an int type so there is no overflow. Good: 100 + (unsigned long)-4 = 96 <-- overflow Bad: 100 + (int)-4 = 96 <-- no overflow I deleted the cast of the sizeof() as well. That's not a bug but the cast is unnecessary. Fixes: 9b0fc3c054ff ("io_uring: fix types in io_recvmsg_multishot_overflow") Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Link: https://lore.kernel.org/r/138bd2e2-ede8-4bcc-aa7b-f3d9de167a37@moroto.mountain Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring/net: move receive multishot out of the generic msghdr pathJens Axboe2024-03-261-70/+91
| | | | | | | | | | | | [ Upstream commit c55978024d123d43808ab393a0a4ce3ce8568150 ] Move the actual user_msghdr / compat_msghdr into the send and receive sides, respectively, so we can move the uaddr receive handling into its own handler, and ditto the multishot with buffer selection logic. Signed-off-by: Jens Axboe <axboe@kernel.dk> Stable-dep-of: 8ede3db5061b ("io_uring/net: fix overflow check in io_recvmsg_mshot_prep()") Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring/net: unify how recvmsg and sendmsg copy in the msghdrJens Axboe2024-03-261-129/+142
| | | | | | | | | | | | | [ Upstream commit 52307ac4f2b507f60bae6df5be938d35e199c688 ] For recvmsg, we roll our own since we support buffer selections. This isn't the case for sendmsg right now, but in preparation for doing so, make the recvmsg copy helpers generic so we can call them from the sendmsg side as well. Signed-off-by: Jens Axboe <axboe@kernel.dk> Stable-dep-of: 8ede3db5061b ("io_uring/net: fix overflow check in io_recvmsg_mshot_prep()") Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring: remove unconditional looping in local task_work handlingJens Axboe2024-03-261-15/+29
| | | | | | | | | | | | | [ Upstream commit 9fe3eaea4a3530ca34a8d8ff00b1848c528789ca ] If we have a ton of notifications coming in, we can be looping in here for a long time. This can be problematic for various reasons, mostly because we can starve userspace. If the application is waiting on N events, then only re-run if we need more events. Fixes: c0e0d6ba25f1 ("io_uring: add IORING_SETUP_DEFER_TASKRUN") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring: remove looping around handling traditional task_workJens Axboe2024-03-261-38/+7
| | | | | | | | | | | | | | | | | | | | [ Upstream commit 592b4805432af075468876771c0f7d41273ccb3c ] A previous commit added looping around handling traditional task_work as an optimization, and while that may seem like a good idea, it's also possible to run into application starvation doing so. If the task_work generation is bursty, we can get very deep task_work queues, and we can end up looping in here for a very long time. One immediately observable problem with that is handling network traffic using provided buffers, where flooding incoming traffic and looping task_work handling will very quickly lead to buffer starvation as we keep running task_work rather than returning to the application so it can handle the associated CQEs and also provide buffers back. Fixes: 3a0c037b0e16 ("io_uring: batch task_work") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring: drop any code related to SCM_RIGHTSJens Axboe2024-03-264-217/+10
| | | | | | | | | | Commit 6e5e6d274956305f1fc0340522b38f5f5be74bdb upstream. This is dead code after we dropped support for passing io_uring fds over SCM_RIGHTS, get rid of it. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring/unix: drop usage of io_uring socketJens Axboe2024-03-262-14/+0
| | | | | | | | | | | | | | | Commit a4104821ad651d8a0b374f0b2474c345bbb42f82 upstream. Since we no longer allow sending io_uring fds over SCM_RIGHTS, move to using io_is_uring_fops() to detect whether this is a io_uring fd or not. With that done, kill off io_uring_get_socket() as nobody calls it anymore. This is in preparation to yanking out the rest of the core related to unix gc with io_uring. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring/net: fix multishot accept overflow handlingJens Axboe2024-02-231-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | commit a37ee9e117ef73bbc2f5c0b31911afd52d229861 upstream. If we hit CQ ring overflow when attempting to post a multishot accept completion, we don't properly save the result or return code. This results in losing the accepted fd value. Instead, we return the result from the poll operation that triggered the accept retry. This is generally POLLIN|POLLPRI|POLLRDNORM|POLLRDBAND which is 0xc3, or 195, which looks like a valid file descriptor, but it really has no connection to that. Handle this like we do for other multishot completions - assign the result, and return IOU_STOP_MULTISHOT to cancel any further completions from this request when overflow is hit. This preserves the result, as we should, and tells the application that the request needs to be re-armed. Cc: stable@vger.kernel.org Fixes: 515e26961295 ("io_uring: revert "io_uring fix multishot accept ordering"") Link: https://github.com/axboe/liburing/issues/1062 Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* io_uring/net: limit inline multishot retriesJens Axboe2024-02-161-3/+20
| | | | | | | | | | | | | | | | | | | | | | | | | Commit 76b367a2d83163cf19173d5cb0b562acbabc8eac upstream. If we have multiple clients and some/all are flooding the receives to such an extent that we can retry a LOT handling multishot receives, then we can be starving some clients and hence serving traffic in an imbalanced fashion. Limit multishot retry attempts to some arbitrary value, whose only purpose serves to ensure that we don't keep serving a single connection for way too long. We default to 32 retries, which should be more than enough to provide fairness, yet not so small that we'll spend too much time requeuing rather than handling traffic. Cc: stable@vger.kernel.org Depends-on: 704ea888d646 ("io_uring/poll: add requeue return code from poll multishot handling") Depends-on: 1e5d765a82f ("io_uring/net: un-indent mshot retry path in io_recv_finish()") Depends-on: e84b01a880f6 ("io_uring/poll: move poll execution helpers higher up") Fixes: b3fdea6ecb55 ("io_uring: multishot recv") Fixes: 9bb66906f23e ("io_uring: support multishot in recvmsg") Link: https://github.com/axboe/liburing/issues/1043 Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* io_uring/poll: add requeue return code from poll multishot handlingJens Axboe2024-02-162-1/+15
| | | | | | | | | | | | | | | | | | Commit 704ea888d646cb9d715662944cf389c823252ee0 upstream. Since our poll handling is edge triggered, multishot handlers retry internally until they know that no more data is available. In preparation for limiting these retries, add an internal return code, IOU_REQUEUE, which can be used to inform the poll backend about the handler wanting to retry, but that this should happen through a normal task_work requeue rather than keep hammering on the issue side for this one request. No functional changes in this patch, nobody is using this return code just yet. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* io_uring/rw: ensure poll based multishot read retries appropriatelyJens Axboe2024-02-162-1/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit c79f52f0656eeb3e4a12f7f358f760077ae111b6 upstream. io_read_mshot() always relies on poll triggering retries, and this works fine as long as we do a retry per size of the buffer being read. The buffer size is given by the size of the buffer(s) in the given buffer group ID. But if we're reading less than what is available, then we don't always get to read everything that is available. For example, if the buffers available are 32 bytes and we have 64 bytes to read, then we'll correctly read the first 32 bytes and then wait for another poll trigger before we attempt the next read. This next poll trigger may never happen, in which case we just sit forever and never make progress, or it may trigger at some point in the future, and now we're just delivering the available data much later than we should have. io_read_mshot() could do retries itself, but that is wasteful as we'll be going through all of __io_read() again, and most likely in vain. Rather than do that, bump our poll reference count and have io_poll_check_events() do one more loop and check with vfs_poll() if we have more data to read. If we do, io_read_mshot() will get invoked again directly and we'll read the next chunk. io_poll_multishot_retry() must only get called from inside io_poll_issue(), which is our multishot retry handler, as we know we already "own" the request at this point. Cc: stable@vger.kernel.org Link: https://github.com/axboe/liburing/issues/1041 Fixes: fc68fcda0491 ("io_uring/rw: add support for IORING_OP_READ_MULTISHOT") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* io_uring/net: un-indent mshot retry path in io_recv_finish()Jens Axboe2024-02-161-16/+20
| | | | | | | | | | | | | commit 91e5d765a82fb2c9d0b7ad930d8953208081ddf1 upstream. In preparation for putting some retry logic in there, have the done path just skip straight to the end rather than have too much nesting in here. No functional changes in this patch. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* io_uring/poll: move poll execution helpers higher upJens Axboe2024-02-161-20/+20
| | | | | | | | | | | | commit e84b01a880f635e3084a361afba41f95ff500d12 upstream. In preparation for calling __io_poll_execute() higher up, move the functions to avoid forward declarations. No functional changes in this patch. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* io_uring/net: fix sr->len for IORING_OP_RECV with MSG_WAITALL and buffersJens Axboe2024-02-161-0/+1
| | | | | | | | | | | | | | | | | | | commit 72bd80252feeb3bef8724230ee15d9f7ab541c6e upstream. If we use IORING_OP_RECV with provided buffers and pass in '0' as the length of the request, the length is retrieved from the selected buffer. If MSG_WAITALL is also set and we get a short receive, then we may hit the retry path which decrements sr->len and increments the buffer for a retry. However, the length is still zero at this point, which means that sr->len now becomes huge and import_ubuf() will cap it to MAX_RW_COUNT and subsequently return -EFAULT for the range as a whole. Fix this by always assigning sr->len once the buffer has been selected. Cc: stable@vger.kernel.org Fixes: 7ba89d2af17a ("io_uring: ensure recv and recvmsg handle MSG_WAITALL correctly") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* io_uring: adjust defer tw countingPavel Begunkov2024-01-251-1/+1
| | | | | | | | | | | | | | | | | | | | | [ Upstream commit dc12d1799ce710fd90abbe0ced71e7e1ae0894fc ] The UINT_MAX work item counting bias in io_req_local_work_add() in case of !IOU_F_TWQ_LAZY_WAKE works in a sense that we will not miss a wake up, however it's still eerie. In particular, if we add a lazy work item after a non-lazy one, we'll increment it and get nr_tw==0, and subsequent adds may try to unnecessarily wake up the task, which is though not so likely to happen in real workloads. Half the bias, it's still large enough to be larger than any valid ->cq_wait_nr, which is limited by IORING_MAX_CQ_ENTRIES, but further have a good enough of space before it overflows. Fixes: 8751d15426a31 ("io_uring: reduce scheduling due to tw") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/108b971e958deaf7048342930c341ba90f75d806.1705438669.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* io_uring: ensure local task_work is run on wait timeoutJens Axboe2024-01-251-2/+12
| | | | | | | | | | | | | | | | | commit 6ff1407e24e6fdfa4a16ba9ba551e3d253a26391 upstream. A previous commit added an earlier break condition here, which is fine if we're using non-local task_work as it'll be run on return to userspace. However, if DEFER_TASKRUN is used, then we could be leaving local task_work that is ready to process in the ctx list until next time that we enter the kernel to wait for events. Move the break condition to _after_ we have run task_work. Cc: stable@vger.kernel.org Fixes: 846072f16eed ("io_uring: mimimise io_cqring_wait_schedule") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* io_uring/rw: ensure io->bytes_done is always initializedJens Axboe2024-01-251-3/+7
| | | | | | | | | | | | | | | | | commit 0a535eddbe0dc1de4386046ab849f08aeb2f8faf upstream. If IOSQE_ASYNC is set and we fail importing an iovec for a readv or writev request, then we leave ->bytes_done uninitialized and hence the eventual failure CQE posted can potentially have a random res value rather than the expected -EINVAL. Setup ->bytes_done before potentially failing, so we have a consistent value if we fail the request early. Cc: stable@vger.kernel.org Reported-by: xingwei lee <xrivendell7@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* io_uring: don't check iopoll if request completesPavel Begunkov2024-01-251-1/+5
| | | | | | | | | | | | | | | | commit 9b43ef3d52532a0175ed6654618f7db61d390d2e upstream. IOPOLL request should never return IOU_OK, so the following iopoll queueing check in io_issue_sqe() after getting IOU_OK doesn't make any sense as would never turn true. Let's optimise on that and return a bit earlier. It's also much more resilient to potential bugs from mischieving iopoll implementations. Cc: <stable@vger.kernel.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/2f8690e2fa5213a2ff292fac29a7143c036cdd60.1701390926.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* io_uring/cmd: fix breakage in SOCKET_URING_OP_SIOC* implementationAl Viro2023-12-141-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In 8e9fad0e70b7 "io_uring: Add io_uring command support for sockets" you've got an include of asm-generic/ioctls.h done in io_uring/uring_cmd.c. That had been done for the sake of this chunk - + ret = prot->ioctl(sk, SIOCINQ, &arg); + if (ret) + return ret; + return arg; + case SOCKET_URING_OP_SIOCOUTQ: + ret = prot->ioctl(sk, SIOCOUTQ, &arg); SIOC{IN,OUT}Q are defined to symbols (FIONREAD and TIOCOUTQ) that come from ioctls.h, all right, but the values vary by the architecture. FIONREAD is 0x467F on mips 0x4004667F on alpha, powerpc and sparc 0x8004667F on sh and xtensa 0x541B everywhere else TIOCOUTQ is 0x7472 on mips 0x40047473 on alpha, powerpc and sparc 0x80047473 on sh and xtensa 0x5411 everywhere else ->ioctl() expects the same values it would've gotten from userland; all places where we compare with SIOC{IN,OUT}Q are using asm/ioctls.h, so they pick the correct values. io_uring_cmd_sock(), OTOH, ends up passing the default ones. Fixes: 8e9fad0e70b7 ("io_uring: Add io_uring command support for sockets") Cc: <stable@vger.kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Link: https://lore.kernel.org/r/20231214213408.GT1674809@ZenIV Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/poll: don't enable lazy wake for POLLEXCLUSIVEJens Axboe2023-12-131-3/+17
| | | | | | | | | | | | | | | | | There are a few quirks around using lazy wake for poll unconditionally, and one of them is related the EPOLLEXCLUSIVE. Those may trigger exclusive wakeups, which wake a limited number of entries in the wait queue. If that wake number is less than the number of entries someone is waiting for (and that someone is also using DEFER_TASKRUN), then we can get stuck waiting for more entries while we should be processing the ones we already got. If we're doing exclusive poll waits, flag the request as not being compatible with lazy wakeups. Reported-by: Pavel Begunkov <asml.silence@gmail.com> Fixes: 6ce4a93dbb5b ("io_uring/poll: use IOU_F_TWQ_LAZY_WAKE for wakeups") Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/af_unix: disable sending io_uring over socketsPavel Begunkov2023-12-071-7/+0
| | | | | | | | | | | | | | | | File reference cycles have caused lots of problems for io_uring in the past, and it still doesn't work exactly right and races with unix_stream_read_generic(). The safest fix would be to completely disallow sending io_uring files via sockets via SCM_RIGHT, so there are no possible cycles invloving registered files and thus rendering SCM accounting on the io_uring side unnecessary. Cc: <stable@vger.kernel.org> Fixes: 0091bfc81741b ("io_uring/af_unix: defer registered files gc to io_uring release") Reported-and-suggested-by: Jann Horn <jannh@google.com> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/c716c88321939156909cfa1bd8b0faaf1c804103.1701868795.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: check for buffer list readiness after NULL checkJens Axboe2023-12-051-2/+2
| | | | | | | | | Move the buffer list 'is_ready' check below the validity check for the buffer list for a given group. Fixes: 5cf4f52e6d8a ("io_uring: free io_buffer_list entries via RCU") Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: Fix an NULL vs IS_ERR() bug in io_alloc_pbuf_ring()Dan Carpenter2023-12-051-2/+2
| | | | | | | | | | The io_mem_alloc() function returns error pointers, not NULL. Update the check accordingly. Fixes: b10b73c102a2 ("io_uring/kbuf: recycle freed mapped buffer ring entries") Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Link: https://lore.kernel.org/r/5ed268d3-a997-4f64-bd71-47faa92101ab@moroto.mountain Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: fix mutex_unlock with unreferenced ctxPavel Begunkov2023-12-031-6/+3
| | | | | | | | | | | | | | | | | | | | | | Callers of mutex_unlock() have to make sure that the mutex stays alive for the whole duration of the function call. For io_uring that means that the following pattern is not valid unless we ensure that the context outlives the mutex_unlock() call. mutex_lock(&ctx->uring_lock); req_put(req); // typically via io_req_task_submit() mutex_unlock(&ctx->uring_lock); Most contexts are fine: io-wq pins requests, syscalls hold the file, task works are taking ctx references and so on. However, the task work fallback path doesn't follow the rule. Cc: <stable@vger.kernel.org> Fixes: 04fc6c802d ("io_uring: save ctx put/get for task_work submit") Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/io-uring/CAG48ez3xSoYb+45f1RLtktROJrpiDQ1otNvdR+YLQf7m+Krj5Q@mail.gmail.com/ Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: use fget/fput consistentlyJens Axboe2023-11-282-23/+24
| | | | | | | | | | | | | | | | | | | | Normally within a syscall it's fine to use fdget/fdput for grabbing a file from the file table, and it's fine within io_uring as well. We do that via io_uring_enter(2), io_uring_register(2), and then also for cancel which is invoked from the latter. io_uring cannot close its own file descriptors as that is explicitly rejected, and for the cancel side of things, the file itself is just used as a lookup cookie. However, it is more prudent to ensure that full references are always grabbed. For anything threaded, either explicitly in the application itself or through use of the io-wq worker threads, this is what happens anyway. Generalize it and use fget/fput throughout. Also see the below link for more details. Link: https://lore.kernel.org/io-uring/CAG48ez1htVSO3TqmrF8QcX2WFuYTRM-VZ_N10i-VZgbtg=NNqw@mail.gmail.com/ Suggested-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: free io_buffer_list entries via RCUJens Axboe2023-11-283-15/+56
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | mmap_lock nests under uring_lock out of necessity, as we may be doing user copies with uring_lock held. However, for mmap of provided buffer rings, we attempt to grab uring_lock with mmap_lock already held from do_mmap(). This makes lockdep, rightfully, complain: WARNING: possible circular locking dependency detected 6.7.0-rc1-00009-gff3337ebaf94-dirty #4438 Not tainted ------------------------------------------------------ buf-ring.t/442 is trying to acquire lock: ffff00020e1480a8 (&ctx->uring_lock){+.+.}-{3:3}, at: io_uring_validate_mmap_request.isra.0+0x4c/0x140 but task is already holding lock: ffff0000dc226190 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0x124/0x264 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&mm->mmap_lock){++++}-{3:3}: __might_fault+0x90/0xbc io_register_pbuf_ring+0x94/0x488 __arm64_sys_io_uring_register+0x8dc/0x1318 invoke_syscall+0x5c/0x17c el0_svc_common.constprop.0+0x108/0x130 do_el0_svc+0x2c/0x38 el0_svc+0x4c/0x94 el0t_64_sync_handler+0x118/0x124 el0t_64_sync+0x168/0x16c -> #0 (&ctx->uring_lock){+.+.}-{3:3}: __lock_acquire+0x19a0/0x2d14 lock_acquire+0x2e0/0x44c __mutex_lock+0x118/0x564 mutex_lock_nested+0x20/0x28 io_uring_validate_mmap_request.isra.0+0x4c/0x140 io_uring_mmu_get_unmapped_area+0x3c/0x98 get_unmapped_area+0xa4/0x158 do_mmap+0xec/0x5b4 vm_mmap_pgoff+0x158/0x264 ksys_mmap_pgoff+0x1d4/0x254 __arm64_sys_mmap+0x80/0x9c invoke_syscall+0x5c/0x17c el0_svc_common.constprop.0+0x108/0x130 do_el0_svc+0x2c/0x38 el0_svc+0x4c/0x94 el0t_64_sync_handler+0x118/0x124 el0t_64_sync+0x168/0x16c From that mmap(2) path, we really just need to ensure that the buffer list doesn't go away from underneath us. For the lower indexed entries, they never go away until the ring is freed and we can always sanely reference those as long as the caller has a file reference. For the higher indexed ones in our xarray, we just need to ensure that the buffer list remains valid while we return the address of it. Free the higher indexed io_buffer_list entries via RCU. With that we can avoid needing ->uring_lock inside mmap(2), and simply hold the RCU read lock around the buffer list lookup and address check. To ensure that the arrayed lookup either returns a valid fully formulated entry via RCU lookup, add an 'is_ready' flag that we access with store and release memory ordering. This isn't needed for the xarray lookups, but doesn't hurt either. Since this isn't a fast path, retain it across both types. Similarly, for the allocated array inside the ctx, ensure we use the proper load/acquire as setup could in theory be running in parallel with mmap. While in there, add a few lockdep checks for documentation purposes. Cc: stable@vger.kernel.org Fixes: c56e022c0a27 ("io_uring: add support for user mapped provided buffer ring") Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: prune deferred locked cache when tearing downJens Axboe2023-11-281-0/+8
| | | | | | | | | | | | | | We used to just use our page list for final teardown, which would ensure that we got all the buffers, even the ones that were not on the normal cached list. But while moving to slab for the io_buffers, we know only prune this list, not the deferred locked list that we have. This can cause a leak of memory, if the workload ends up using the intermediate locked list. Fix this by always pruning both lists when tearing down. Fixes: b3a4dbc89d40 ("io_uring/kbuf: Use slab for struct io_buffer objects") Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: recycle freed mapped buffer ring entriesJens Axboe2023-11-281-11/+66
| | | | | | | | | | | | | | Right now we stash any potentially mmap'ed provided ring buffer range for freeing at release time, regardless of when they get unregistered. Since we're keeping track of these ranges anyway, keep track of their registration state as well, and use that to recycle ranges when appropriate rather than always allocate new ones. The lookup is a basic scan of entries, checking for the best matching free entry. Fixes: c392cbecd8ec ("io_uring/kbuf: defer release of mapped buffer rings") Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/kbuf: defer release of mapped buffer ringsJens Axboe2023-11-283-5/+43
| | | | | | | | | | | | | | | | If a provided buffer ring is setup with IOU_PBUF_RING_MMAP, then the kernel allocates the memory for it and the application is expected to mmap(2) this memory. However, io_uring uses remap_pfn_range() for this operation, so we cannot rely on normal munmap/release on freeing them for us. Stash an io_buf_free entry away for each of these, if any, and provide a helper to free them post ->release(). Cc: stable@vger.kernel.org Fixes: c56e022c0a27 ("io_uring: add support for user mapped provided buffer ring") Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: enable io_mem_alloc/free to be used in other partsJens Axboe2023-11-272-2/+5
| | | | | | | In preparation for using these helpers, make them non-static and add them to our internal header. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: don't guard IORING_OFF_PBUF_RING with SETUP_NO_MMAPJens Axboe2023-11-271-4/+6
| | | | | | | | | | This flag only applies to the SQ and CQ rings, it's perfectly valid to use a mmap approach for the provided ring buffers. Move the check into where it belongs. Cc: stable@vger.kernel.org Fixes: 03d89a2de25b ("io_uring: support for user allocated memory for rings/sqes") Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: don't allow discontig pages for IORING_SETUP_NO_MMAPJens Axboe2023-11-271-18/+21
| | | | | | | | | | | | | | | | | | | io_sqes_map() is used rather than io_mem_alloc(), if the application passes in memory for mapping rather than have the kernel allocate it and then mmap(2) the ranges. This then calls __io_uaddr_map() to perform the page mapping and pinning, which checks if we end up with the same pages, if more than one page is mapped. But this check is incorrect and only checks if the first and last pages are the same, where it really should be checking if the mapped pages are contigous. This allows mapping a single normal page, or a huge page range. Down the line we can add support for remapping pages to be virtually contigous, which is really all that io_uring cares about. Cc: stable@vger.kernel.org Fixes: 03d89a2de25b ("io_uring: support for user allocated memory for rings/sqes") Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: fix off-by one bvec indexKeith Busch2023-11-201-1/+1
| | | | | | | | | | | | | If the offset equals the bv_len of the first registered bvec, then the request does not include any of that first bvec. Skip it so that drivers don't have to deal with a zero length bvec, which was observed to break NVMe's PRP list creation. Cc: stable@vger.kernel.org Fixes: bd11b3a391e3 ("io_uring: don't use iov_iter_advance() for fixed buffers") Signed-off-by: Keith Busch <kbusch@kernel.org> Link: https://lore.kernel.org/r/20231120221831.2646460-1-kbusch@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/fs: consider link->flags when getting path for LINKATCharles Mirabile2023-11-201-1/+1
| | | | | | | | | | | | | In order for `AT_EMPTY_PATH` to work as expected, the fact that the user wants that behavior needs to make it to `getname_flags` or it will return ENOENT. Fixes: cf30da90bc3a ("io_uring: add support for IORING_OP_LINKAT") Cc: <stable@vger.kernel.org> Link: https://github.com/axboe/liburing/issues/995 Signed-off-by: Charles Mirabile <cmirabil@redhat.com> Link: https://lore.kernel.org/r/20231120105545.1209530-1-cmirabil@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/fdinfo: remove need for sqpoll lock for thread/pid retrievalJens Axboe2023-11-152-9/+12
| | | | | | | | | | | | | | | | | | | | | | | A previous commit added a trylock for getting the SQPOLL thread info via fdinfo, but this introduced a regression where we often fail to get it if the thread is busy. For that case, we end up not printing the current CPU and PID info. Rather than rely on this lock, just print the pid we already stored in the io_sq_data struct, and ensure we update the current CPU every time we've slept or potentially rescheduled. The latter won't potentially be 100% accurate, but that wasn't the case before either as the task can get migrated at any time unless it has been pinned at creation time. We retain keeping the io_sq_data dereference inside the ctx->uring_lock, as it has always been, as destruction of the thread and data happen below that. We could make this RCU safe, but there's little point in doing that. With this, we always print the last valid information we had, rather than have spurious outputs with missing information. Fixes: 7644b1a1c9a7 ("io_uring/fdinfo: lock SQ thread while retrieving thread cpu/pid") Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: do not clamp read length for multishot readDylan Yudaken2023-11-061-1/+8
| | | | | | | | | | | | | | | | | | When doing a multishot read, the code path reuses the old read paths. However this breaks an assumption built into those paths, namely that struct io_rw::len is available for reuse by __io_import_iovec. For multishot this results in len being set for the first receive call, and then subsequent calls are clamped to that buffer length incorrectly. Instead keep len as zero after recycling buffers, to reuse the full buffer size of the next selected buffer. Fixes: fc68fcda0491 ("io_uring/rw: add support for IORING_OP_READ_MULTISHOT") Signed-off-by: Dylan Yudaken <dyudaken@gmail.com> Link: https://lore.kernel.org/r/20231106203909.197089-4-dyudaken@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: do not allow multishot read to set addr or lenDylan Yudaken2023-11-061-0/+4
| | | | | | | | | | | | | | | For addr: this field is not used, since buffer select is forced. But by forcing it to be zero it leaves open future uses of the field. len is actually usable, you could imagine that you want to receive multishot up to a certain length. However right now this is not how it is implemented, and it seems safer to force this to be zero. Fixes: fc68fcda0491 ("io_uring/rw: add support for IORING_OP_READ_MULTISHOT") Signed-off-by: Dylan Yudaken <dyudaken@gmail.com> Link: https://lore.kernel.org/r/20231106203909.197089-3-dyudaken@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: indicate if io_kbuf_recycle did recycle anythingDylan Yudaken2023-11-062-8/+11
| | | | | | | | | It can be useful to know if io_kbuf_recycle did actually recycle the buffer on the request, or if it left the request alone. Signed-off-by: Dylan Yudaken <dyudaken@gmail.com> Link: https://lore.kernel.org/r/20231106203909.197089-2-dyudaken@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
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