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2019-12-02Merge tag 'for-linus-20191129' of git://git.kernel.dk/linux-blockLinus Torvalds1-6/+52
Pull block fixes from Jens Axboe: "I wasn't going to send this one off so soon, but unfortunately one of the fixes from the previous pull broke the build on some archs. So I'm sending this sooner rather than later. This contains: - Add highmem.h include for io_uring, because of the kmap() additions from last round. For some reason the build bot didn't spot this even though it sat for days. - Three minor ';' removals - Add support for the Beurer CD-on-a-chip device - Make io_uring work on MMU-less archs" * tag 'for-linus-20191129' of git://git.kernel.dk/linux-block: io_uring: fix missing kmap() declaration on powerpc ataflop: Remove unneeded semicolon block: sunvdc: Remove unneeded semicolon drbd: Remove unneeded semicolon io_uring: add mapping support for NOMMU archs sr_vendor: support Beurer GL50 evo CD-on-a-chip devices. cdrom: respect device capabilities during opening action
2019-11-29io_uring: fix missing kmap() declaration on powerpcJens Axboe1-0/+1
Christophe reports that current master fails building on powerpc with this error: CC fs/io_uring.o fs/io_uring.c: In function ‘loop_rw_iter’: fs/io_uring.c:1628:21: error: implicit declaration of function ‘kmap’ [-Werror=implicit-function-declaration] iovec.iov_base = kmap(iter->bvec->bv_page) ^ fs/io_uring.c:1628:19: warning: assignment makes pointer from integer without a cast [-Wint-conversion] iovec.iov_base = kmap(iter->bvec->bv_page) ^ fs/io_uring.c:1643:4: error: implicit declaration of function ‘kunmap’ [-Werror=implicit-function-declaration] kunmap(iter->bvec->bv_page); ^ which is caused by a missing highmem.h include. Fix it by including it. Fixes: 311ae9e159d8 ("io_uring: fix dead-hung for non-iter fixed rw") Reported-by: Christophe Leroy <christophe.leroy@c-s.fr> Tested-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-28io_uring: add mapping support for NOMMU archsRoman Penyaev1-6/+51
That is a bit weird scenario but I find it interesting to run fio loads using LKL linux, where MMU is disabled. Probably other real archs which run uClinux can also benefit from this patch. Signed-off-by: Roman Penyaev <rpenyaev@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27io_uring: make poll->wait dynamically allocatedJens Axboe1-12/+17
In the quest to bring io_kiocb down to 3 cachelines, this one does the trick. Make the wait_queue_entry for the poll command come out of kmalloc instead of embedding it in struct io_poll_iocb, as the latter is the largest member of io_kiocb. Once we trim this down a bit, we're back at a healthy 192 bytes for struct io_kiocb. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27io_uring: cleanup io_import_fixed()Pavel Begunkov1-7/+5
Clean io_import_fixed() call site and make it return proper type. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27io_uring: inline struct sqe_submitPavel Begunkov1-91/+78
There is no point left in keeping struct sqe_submit. Inline it into struct io_kiocb, so any req->submit.field is now just req->field - moves initialisation of ring_file into io_get_req() - removes duplicated req->sequence. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-27io_uring: store timeout's sqe->off in proper placePavel Begunkov1-4/+5
Timeouts' sequence offset (i.e. sqe->off) is stored in req->submit.sequence under a false name. Keep it in timeout.data instead. The unused space for sequence will be reclaimed in the following patches. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: remove superfluous check for sqe->off in io_accept()Hrvoje Zeba1-1/+1
This field contains a pointer to addrlen and checking to see if it's set returns -EINVAL if the caller sets addr & addrlen pointers. Fixes: 17f2fe35d080 ("io_uring: add support for IORING_OP_ACCEPT") Signed-off-by: Hrvoje Zeba <zeba.hrvoje@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: async workers should inherit the user credsJens Axboe1-0/+8
If we don't inherit the original task creds, then we can confuse users like fuse that pass creds in the request header. See link below on identical aio issue. Link: https://lore.kernel.org/linux-fsdevel/26f0d78e-99ca-2f1b-78b9-433088053a61@scylladb.com/T/#u Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io-wq: have io_wq_create() take a 'data' argumentJens Axboe1-2/+7
We currently pass in 4 arguments outside of the bounded size. In preparation for adding one more argument, let's bundle them up in a struct to make it more readable. No functional changes in this patch. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: fix dead-hung for non-iter fixed rwPavel Begunkov1-1/+14
Read/write requests to devices without implemented read/write_iter using fixed buffers can cause general protection fault, which totally hangs a machine. io_import_fixed() initialises iov_iter with bvec, but loop_rw_iter() accesses it as iovec, dereferencing random address. kmap() page by page in this case Cc: stable@vger.kernel.org Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: add support for IORING_OP_CONNECTJens Axboe1-0/+36
This allows an application to call connect() in an async fashion. Like other opcodes, we first try a non-blocking connect, then punt to async context if we have to. Note that we can still return -EINPROGRESS, and in that case the caller should use IORING_OP_POLL_ADD to do an async wait for completion of the connect request (just like for regular connect(2), except we can do it async here too). Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: only return -EBUSY for submit on non-flushed backlogJens Axboe1-6/+10
We return -EBUSY on submit when we have a CQ ring overflow backlog, but that can be a bit problematic if the application is using pure userspace poll of the CQ ring. For that case, if the ring briefly overflowed and we have pending entries in the backlog, the submit flushes the backlog successfully but still returns -EBUSY. If we're able to fully flush the CQ ring backlog, let the submission proceed. Reported-by: Dan Melnic <dmm@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: only !null ptr to io_issue_sqe()Pavel Begunkov1-16/+12
Pass only non-null @nxt to io_issue_sqe() and handle it at the caller's side. And propagate it. - kiocb_done() is only called from io_read() and io_write(), which are only called from io_issue_sqe(), so it's @nxt != NULL - io_put_req_find_next() is called either with explicitly non-null local nxt, or from one of the functions in io_issue_sqe() switch (or their callees). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: simplify io_req_link_next()Pavel Begunkov1-10/+1
"if (nxt)" is always true, as it was checked in the while's condition. io_wq_current_is_worker() is unnecessary, as non-async callers don't pass nxt, so io_queue_async_work() will be called for them anyway. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: pass only !null to io_req_find_next()Pavel Begunkov1-2/+7
Make io_req_find_next() and io_req_link_next() to accept only non-null nxt, and handle it in callers. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: remove io_free_req_find_next()Pavel Begunkov1-7/+2
There is only one one-liner user of io_free_req_find_next(). Inline it. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: add likely/unlikely in io_get_sqring()Pavel Begunkov1-2/+2
The number of SQEs to submit is specified by a user, so io_get_sqring() in most of the cases succeeds. Hint compilers about that. Checking ASM genereted by gcc 9.2.0 for x64, there is one branch misprediction. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: rename __io_submit_sqe()Pavel Begunkov1-4/+4
__io_submit_sqe() is issuing requests, so call it as such. Moreover, it ends by calling io_iopoll_req_issued(). Rename it and make terminology clearer. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: improve trace_io_uring_defer() trace pointJens Axboe1-1/+1
We don't have shadow requests anymore, so get rid of the shadow argument. Add the user_data argument, as that's often useful to easily match up requests, instead of having to look at request pointers. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: drain next sqe instead of shadowingPavel Begunkov1-68/+18
There's an issue with the shadow drain logic in that we drop the completion lock after deciding to defer a request, then re-grab it later and assume that the state is still the same. In the mean time, someone else completing a request could have found and issued it. This can cause a stall in the queue, by having a shadow request inserted that nobody is going to drain. Additionally, if we fail allocating the shadow request, we simply ignore the drain. Instead of using a shadow request, defer the next request/link instead. This also has the following advantages: - removes semi-duplicated code - doesn't allocate memory for shadows - works better if only the head marked for drain - doesn't need complex synchronisation On the flip side, it removes the shadow->seq == last_drain_in_in_link->seq optimization. That shouldn't be a common case, and can always be added back, if needed. Fixes: 4fe2c963154c ("io_uring: add support for link with drain") Cc: Jackie Liu <liuyun01@kylinos.cn> Reported-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: close lookup gap for dependent next workJens Axboe1-2/+14
When we find new work to process within the work handler, we queue the linked timeout before we have issued the new work. This can be problematic for very short timeouts, as we have a window where the new work isn't visible. Allow the work handler to store a callback function for this in the work item, and flag it with IO_WQ_WORK_CB if the caller has done so. If that is set, then io-wq will call the callback when it has setup the new work item. Reported-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: allow finding next link independent of req reference countJens Axboe1-5/+15
We currently try and start the next link when we put the request, and only if we were going to free it. This means that the optimization to continue executing requests from the same context often fails, as we're not putting the final reference. Add REQ_F_LINK_NEXT to keep track of this, and allow io_uring to find the next request more efficiently. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: io_allocate_scq_urings() should return a sane stateJens Axboe1-2/+8
We currently rely on the ring destroy on cleaning things up in case of failure, but io_allocate_scq_urings() can leave things half initialized if only parts of it fails. Be nice and return with either everything setup in success, or return an error with things nicely cleaned up. Reported-by: syzbot+0d818c0d39399188f393@syzkaller.appspotmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: Always REQ_F_FREE_SQE for allocated sqePavel Begunkov1-27/+22
Always mark requests with allocated sqe and deallocate it in __io_free_req(). It's easier to follow and doesn't add edge cases. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: io_fail_links() should only consider first linked timeoutJens Axboe1-3/+4
We currently clear the linked timeout field if we cancel such a timeout, but we should only attempt to cancel if it's the first one we see. Others should simply be freed like other requests, as they haven't been started yet. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: Fix leaking linked timeoutsPavel Begunkov1-0/+1
let have a dependant link: REQ -> LINK_TIMEOUT -> LINK_TIMEOUT 1. submission stage: submission references for REQ and LINK_TIMEOUT are dropped. So, references respectively (1,1,2) 2. io_put(REQ) + FAIL_LINKS stage: calls io_fail_links(), which for all linked timeouts will call cancel_timeout() and drop 1 reference. So, references after: (0,0,1). That's a leak. Make it treat only the first linked timeout as such, and pass others through __io_double_put_req(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: remove redundant checkPavel Begunkov1-4/+0
Pass any IORING_OP_LINK_TIMEOUT request further, where it will eventually fail in io_issue_sqe(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: break links for failed deferPavel Begunkov1-0/+4
If io_req_defer() failed, it needs to cancel a dependant link. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: request cancellations should break linksJens Axboe1-0/+6
We currently don't explicitly break links if a request is cancelled, but we should. Add explicitly link breakage for all types of request cancellations that we support. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: correct poll cancel and linked timeout expiration completionJens Axboe1-11/+22
Currently a poll request fills a completion entry of 0, even if it got cancelled. This is odd, and it makes it harder to support with chains. Ensure that it returns -ECANCELED in the completions events if it got cancelled, and furthermore ensure that the linked timeout that triggered it completes with -ETIME if we did indeed trigger the completions through a timeout. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: remove dead REQ_F_SEQ_PREV flagJens Axboe1-1/+0
With the conversion to io-wq, we no longer use that flag. Kill it. Fixes: 561fb04a6a22 ("io_uring: replace workqueue usage with io-wq") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: fix sequencing issues with linked timeoutsJens Axboe1-41/+61
We have an issue with timeout links that are deeper in the submit chain, because we only handle it upfront, not from later submissions. Move the prep + issue of the timeout link to the async work prep handler, and do it normally for non-async queue. If we validate and prepare the timeout links upfront when we first see them, there's nothing stopping us from supporting any sort of nesting. Fixes: 2665abfd757f ("io_uring: add support for linked SQE timeouts") Reported-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: make req->timeout be dynamically allocatedJens Axboe1-59/+70
There are a few reasons for this: - As a prep to improving the linked timeout logic - io_timeout is the biggest member in the io_kiocb opcode union This also enables a few cleanups, like unifying the timer setup between IORING_OP_TIMEOUT and IORING_OP_LINK_TIMEOUT, and not needing multiple arguments to the link/prep helpers. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: make io_double_put_req() use normal completion pathJens Axboe1-2/+14
If we don't use the normal completion path, we may skip killing links that should be errored and freed. Add __io_double_put_req() for use within the completion path itself, other calls should just use io_double_put_req(). Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: cleanup return values from the queueing functionsJens Axboe1-16/+12
__io_queue_sqe(), io_queue_sqe(), io_queue_link_head() all return 0/err, but the caller doesn't care since the errors are handled inline. Clean these up and just make them void. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-26io_uring: io_async_cancel() should pass in 'nxt' request pointerJens Axboe1-1/+1
If we have a linked request, this enables us to pass it back directly without having to go through async context. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-25Merge tag 'for-5.5/io_uring-20191121' of git://git.kernel.dk/linux-blockLinus Torvalds1-694/+1503
Pull io_uring updates from Jens Axboe: "A lot of stuff has been going on this cycle, with improving the support for networked IO (and hence unbounded request completion times) being one of the major themes. There's been a set of fixes done this week, I'll send those out as well once we're certain we're fully happy with them. This contains: - Unification of the "normal" submit path and the SQPOLL path (Pavel) - Support for sparse (and bigger) file sets, and updating of those file sets without needing to unregister/register again. - Independently sized CQ ring, instead of just making it always 2x the SQ ring size. This makes it more flexible for networked applications. - Support for overflowed CQ ring, never dropping events but providing backpressure on submits. - Add support for absolute timeouts, not just relative ones. - Support for generic cancellations. This divorces io_uring from workqueues as well, which additionally gets us one step closer to generic async system call support. - With cancellations, we can support grabbing the process file table as well, just like we do mm context. This allows support for system calls that create file descriptors, like accept4() support that's built on top of that. - Support for io_uring tracing (Dmitrii) - Support for linked timeouts. These abort an operation if it isn't completed by the time noted in the linke timeout. - Speedup tracking of poll requests - Various cleanups making the coder easier to follow (Jackie, Pavel, Bob, YueHaibing, me) - Update MAINTAINERS with new io_uring list" * tag 'for-5.5/io_uring-20191121' of git://git.kernel.dk/linux-block: (64 commits) io_uring: make POLL_ADD/POLL_REMOVE scale better io-wq: remove now redundant struct io_wq_nulls_list io_uring: Fix getting file for non-fd opcodes io_uring: introduce req_need_defer() io_uring: clean up io_uring_cancel_files() io-wq: ensure free/busy list browsing see all items io-wq: ensure we have a stable view of ->cur_work for cancellations io_wq: add get/put_work handlers to io_wq_create() io_uring: check for validity of ->rings in teardown io_uring: fix potential deadlock in io_poll_wake() io_uring: use correct "is IO worker" helper io_uring: fix -ENOENT issue with linked timer with short timeout io_uring: don't do flush cancel under inflight_lock io_uring: flag SQPOLL busy condition to userspace io_uring: make ASYNC_CANCEL work with poll and timeout io_uring: provide fallback request for OOM situations io_uring: convert accept4() -ERESTARTSYS into -EINTR io_uring: fix error clear of ->file_table in io_sqe_files_register() io_uring: separate the io_free_req and io_free_req_find_next interface io_uring: keep io_put_req only responsible for release and put req ...
2019-11-14io_uring: make POLL_ADD/POLL_REMOVE scale betterJens Axboe1-15/+54
One of the obvious use cases for these commands is networking, where it's not uncommon to have tons of sockets open and polled for. The current implementation uses a list for insertion and lookup, which works fine for file based use cases where the count is usually low, it breaks down somewhat for higher number of files / sockets. A test case with 30k sockets being polled for and cancelled takes: real 0m6.968s user 0m0.002s sys 0m6.936s with the patch it takes: real 0m0.233s user 0m0.010s sys 0m0.176s If you go to 50k sockets, it gets even more abysmal with the current code: real 0m40.602s user 0m0.010s sys 0m40.555s with the patch it takes: real 0m0.398s user 0m0.000s sys 0m0.341s Change is pretty straight forward, just replace the cancel_list with a red/black tree instead. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14io_uring: Fix getting file for non-fd opcodesPavel Begunkov1-0/+4
For timeout requests and bunch of others io_uring tries to grab a file with specified fd, which is usually stdin/fd=0. Update io_op_needs_file() Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14io_uring: introduce req_need_defer()Bob Liu1-9/+10
Makes the code easier to read. Signed-off-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14io_uring: clean up io_uring_cancel_files()Bob Liu1-6/+3
We don't use the return value anymore, drop it. Also drop the unecessary double cancel_req value check. Signed-off-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14io_uring: ensure registered buffer import returns the IO lengthJens Axboe1-1/+1
A test case was reported where two linked reads with registered buffers failed the second link always. This is because we set the expected value of a request in req->result, and if we don't get this result, then we fail the dependent links. For some reason the registered buffer import returned -ERROR/0, while the normal import returns -ERROR/length. This broke linked commands with registered buffers. Fix this by making io_import_fixed() correctly return the mapped length. Cc: stable@vger.kernel.org # v5.3 Reported-by: 李通洲 <carter.li@eoitek.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-14io_uring: Fix getting file for timeoutPavel Begunkov1-0/+1
For timeout requests io_uring tries to grab a file with specified fd, which is usually stdin/fd=0. Update io_op_needs_file() Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-13io_wq: add get/put_work handlers to io_wq_create()Jens Axboe1-1/+16
For cancellation, we need to ensure that the work item stays valid for as long as ->cur_work is valid. Right now we can't safely dereference the work item even under the wqe->lock, because while the ->cur_work pointer will remain valid, the work could be completing and be freed in parallel. Only invoke ->get/put_work() on items we know that the caller queued themselves. Add IO_WQ_WORK_INTERNAL for io-wq to use, which is needed when we're queueing a flush item, for instance. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-13io_uring: check for validity of ->rings in teardownJens Axboe1-1/+3
Normally the rings are always valid, the exception is if we failed to allocate the rings at setup time. syzbot reports this: RSP: 002b:00007ffd6e8aa078 EFLAGS: 00000246 ORIG_RAX: 00000000000001a9 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441229 RDX: 0000000000000002 RSI: 0000000020000140 RDI: 0000000000000d0d RBP: 00007ffd6e8aa090 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000000 kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 8903 Comm: syz-executor410 Not tainted 5.4.0-rc7-next-20191113 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__read_once_size include/linux/compiler.h:199 [inline] RIP: 0010:__io_commit_cqring fs/io_uring.c:496 [inline] RIP: 0010:io_commit_cqring+0x1e1/0xdb0 fs/io_uring.c:592 Code: 03 0f 8e df 09 00 00 48 8b 45 d0 4c 8d a3 c0 00 00 00 4c 89 e2 48 c1 ea 03 44 8b b8 c0 01 00 00 48 b8 00 00 00 00 00 fc ff df <0f> b6 14 02 4c 89 e0 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 61 RSP: 0018:ffff88808f51fc08 EFLAGS: 00010006 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff815abe4a RDX: 0000000000000018 RSI: ffffffff81d168d5 RDI: ffff8880a9166100 RBP: ffff88808f51fc70 R08: 0000000000000004 R09: ffffed1011ea3f7d R10: ffffed1011ea3f7c R11: 0000000000000003 R12: 00000000000000c0 R13: ffff8880a91661c0 R14: 1ffff1101522cc10 R15: 0000000000000000 FS: 0000000001e7a880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000140 CR3: 000000009a74c000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: io_cqring_overflow_flush+0x6b9/0xa90 fs/io_uring.c:673 io_ring_ctx_wait_and_kill+0x24f/0x7c0 fs/io_uring.c:4260 io_uring_create fs/io_uring.c:4600 [inline] io_uring_setup+0x1256/0x1cc0 fs/io_uring.c:4626 __do_sys_io_uring_setup fs/io_uring.c:4639 [inline] __se_sys_io_uring_setup fs/io_uring.c:4636 [inline] __x64_sys_io_uring_setup+0x54/0x80 fs/io_uring.c:4636 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x441229 Code: e8 5c ae 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 bb 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffd6e8aa078 EFLAGS: 00000246 ORIG_RAX: 00000000000001a9 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441229 RDX: 0000000000000002 RSI: 0000000020000140 RDI: 0000000000000d0d RBP: 00007ffd6e8aa090 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000000 Modules linked in: ---[ end trace b0f5b127a57f623f ]--- RIP: 0010:__read_once_size include/linux/compiler.h:199 [inline] RIP: 0010:__io_commit_cqring fs/io_uring.c:496 [inline] RIP: 0010:io_commit_cqring+0x1e1/0xdb0 fs/io_uring.c:592 Code: 03 0f 8e df 09 00 00 48 8b 45 d0 4c 8d a3 c0 00 00 00 4c 89 e2 48 c1 ea 03 44 8b b8 c0 01 00 00 48 b8 00 00 00 00 00 fc ff df <0f> b6 14 02 4c 89 e0 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 61 RSP: 0018:ffff88808f51fc08 EFLAGS: 00010006 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff815abe4a RDX: 0000000000000018 RSI: ffffffff81d168d5 RDI: ffff8880a9166100 RBP: ffff88808f51fc70 R08: 0000000000000004 R09: ffffed1011ea3f7d R10: ffffed1011ea3f7c R11: 0000000000000003 R12: 00000000000000c0 R13: ffff8880a91661c0 R14: 1ffff1101522cc10 R15: 0000000000000000 FS: 0000000001e7a880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000140 CR3: 000000009a74c000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 which is exactly the case of failing to allocate the SQ/CQ rings, and then entering shutdown. Check if the rings are valid before trying to access them at shutdown time. Reported-by: syzbot+21147d79607d724bd6f3@syzkaller.appspotmail.com Fixes: 1d7bb1d50fb4 ("io_uring: add support for backlogged CQ ring") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-12io_uring: fix potential deadlock in io_poll_wake()Jens Axboe1-3/+12
We attempt to run the poll completion inline, but we're using trylock to do so. This avoids a deadlock since we're grabbing the locks in reverse order at this point, we already hold the poll wq lock and we're trying to grab the completion lock, while the normal rules are the reverse of that order. IO completion for a timeout link will need to grab the completion lock, but that's not safe from this context. Put the completion under the completion_lock in io_poll_wake(), and mark the request as entering the completion with the completion_lock already held. Fixes: 2665abfd757f ("io_uring: add support for linked SQE timeouts") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-12io_uring: use correct "is IO worker" helperJens Axboe1-1/+1
Since we switched to io-wq, the dependent link optimization for when to pass back work inline has been broken. Fix this by providing a suitable io-wq helper for io_uring to use to detect when to do this. Fixes: 561fb04a6a22 ("io_uring: replace workqueue usage with io-wq") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-12io_uring: make timeout sequence == 0 mean no sequenceJens Axboe1-7/+22
Currently we make sequence == 0 be the same as sequence == 1, but that's not super useful if the intent is really to have a timeout that's just a pure timeout. If the user passes in sqe->off == 0, then don't apply any sequence logic to the request, let it purely be driven by the timeout specified. Reported-by: 李通洲 <carter.li@eoitek.com> Reviewed-by: 李通洲 <carter.li@eoitek.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-12io_uring: fix -ENOENT issue with linked timer with short timeoutJens Axboe1-51/+72
If you prep a read (for example) that needs to get punted to async context with a timer, if the timeout is sufficiently short, the timer request will get completed with -ENOENT as it could not find the read. The issue is that we prep and start the timer before we start the read. Hence the timer can trigger before the read is even started, and the end result is then that the timer completes with -ENOENT, while the read starts instead of being cancelled by the timer. Fix this by splitting the linked timer into two parts: 1) Prep and validate the linked timer 2) Start timer The read is then started between steps 1 and 2, so we know that the timer will always have a consistent view of the read request state. Reported-by: Hrvoje Zeba <zeba.hrvoje@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>