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10 daysio_uring/poll: fix POLLERR handlingPavel Begunkov
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 Chang
[ 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>
2025-07-06io_uring/kbuf: flag partial buffer mappingsJens Axboe
A previous commit aborted mapping more for a non-incremental ring for bundle peeking, but depending on where in the process this peeking happened, it would not necessarily prevent a retry by the user. That can create gaps in the received/read data. Add struct buf_sel_arg->partial_map, which can pass this information back. The networking side can then map that to internal state and use it to gate retry as well. Since this necessitates a new flag, change io_sr_msg->retry to a retry_flags member, and store both the retry and partial map condition in there. Cc: stable@vger.kernel.org Fixes: 26ec15e4b0c1 ("io_uring/kbuf: don't truncate end buffer for multiple buffer peeks") Signed-off-by: Jens Axboe <axboe@kernel.dk> (cherry picked from commit 178b8ff66ff827c41b4fa105e9aabb99a0b5c537) Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-06io_uring/net: mark iov as dynamically allocated even for single segmentsJens Axboe
Commit 9a709b7e98e6fa51600b5f2d24c5068efa6d39de upstream. A bigger array of vecs could've been allocated, but io_ring_buffers_peek() still decided to cap the mapped range depending on how much data was available. Hence don't rely on the segment count to know if the request should be marked as needing cleanup, always check upfront if the iov array is different than the fast_iov array. Fixes: 26ec15e4b0c1 ("io_uring/kbuf: don't truncate end buffer for multiple buffer peeks") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-06io_uring/net: always use current transfer count for buffer putJens Axboe
A previous fix corrected the retry condition for when to continue a current bundle, but it missed that the current (not the total) transfer count also applies to the buffer put. If not, then for incrementally consumed buffer rings repeated completions on the same request may end up over consuming. Reported-by: Roy Tang (ErgoniaTrading) <royonia@ergonia.io> Cc: stable@vger.kernel.org Fixes: 3a08988123c8 ("io_uring/net: only retry recv bundle for a full transfer") Link: https://github.com/axboe/liburing/issues/1423 Signed-off-by: Jens Axboe <axboe@kernel.dk> (cherry picked from commit 51a4598ad5d9eb6be4ec9ba65bbfdf0ac302eb2e) Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-06io_uring/net: only consider msg_inq if larger than 1Jens Axboe
Commit 2c7f023219966777be0687e15b57689894304cd3 upstream. Currently retry and general validity of msg_inq is gated on it being larger than zero, but it's entirely possible for this to be slightly inaccurate. In particular, if FIN is received, it'll return 1. Just use larger than 1 as the check. This covers both the FIN case, and at the same time, it doesn't make much sense to retry a recv immediately if there's even just a single 1 byte of valid data in the socket. Leave the SOCK_NONEMPTY flagging when larger than 0 still, as an app may use that for the final receive. Cc: stable@vger.kernel.org Reported-by: Christian Mazakas <christian.mazakas@gmail.com> Fixes: 7c71a0af81ba ("io_uring/net: improve recv bundles") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-06io_uring/net: only retry recv bundle for a full transferJens Axboe
Commit 3a08988123c868dbfdd054541b1090fb891fa49e upstream. If a shorter than assumed transfer was seen, a partial buffer will have been filled. For that case it isn't sane to attempt to fill more into the bundle before posting a completion, as that will cause a gap in the received data. Check if the iterator has hit zero and only allow to continue a bundle operation if that is the case. Also ensure that for putting finished buffers, only the current transfer is accounted. Otherwise too many buffers may be put for a short transfer. Link: https://github.com/axboe/liburing/issues/1409 Cc: stable@vger.kernel.org Fixes: 7c71a0af81ba ("io_uring/net: improve recv bundles") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-06io_uring/net: improve recv bundlesJens Axboe
Commit 7c71a0af81ba72de9b2c501065e4e718aba9a271 upstream. Current recv bundles are only supported for multishot receives, and additionally they also always post at least 2 CQEs if more data is available than what a buffer will hold. This happens because the initial bundle recv will do a single buffer, and then do the rest of what is in the socket as a followup receive. As shown in a test program, if 1k buffers are available and 32k is available to receive in the socket, you'd get the following completions: bundle=1, mshot=0 cqe res 1024 cqe res 1024 [...] cqe res 1024 bundle=1, mshot=1 cqe res 1024 cqe res 31744 where bundle=1 && mshot=0 will post 32 1k completions, and bundle=1 && mshot=1 will post a 1k completion and then a 31k completion. To support bundle recv without multishot, it's possible to simply retry the recv immediately and post a single completion, rather than split it into two completions. With the below patch, the same test looks as follows: bundle=1, mshot=0 cqe res 32768 bundle=1, mshot=1 cqe res 32768 where mshot=0 works fine for bundles, and both of them post just a single 32k completion rather than split it into separate completions. Posting fewer completions is always a nice win, and not needing multishot for proper bundle efficiency is nice for cases that can't necessarily use multishot. Reported-by: Norman Maurer <norman_maurer@apple.com> Link: https://lore.kernel.org/r/184f9f92-a682-4205-a15d-89e18f664502@kernel.dk Fixes: 2f9c9515bdfd ("io_uring/net: support bundles for recv") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-06io_uring/rsrc: don't rely on user vaddr alignmentPavel Begunkov
Commit 3a3c6d61577dbb23c09df3e21f6f9eda1ecd634b upstream. There is no guaranteed alignment for user pointers, however the calculation of an offset of the first page into a folio after coalescing uses some weird bit mask logic, get rid of it. Cc: stable@vger.kernel.org Reported-by: David Hildenbrand <david@redhat.com> Fixes: a8edbb424b139 ("io_uring/rsrc: enable multi-hugepage buffer coalescing") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/io-uring/e387b4c78b33f231105a601d84eefd8301f57954.1750771718.git.asml.silence@gmail.com/ Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-06io_uring/rsrc: fix folio unpinningPavel Begunkov
Commit 5afb4bf9fc62d828647647ec31745083637132e4 upstream. syzbot complains about an unmapping failure: [ 108.070381][ T14] kernel BUG at mm/gup.c:71! [ 108.070502][ T14] Internal error: Oops - BUG: 00000000f2000800 [#1] SMP [ 108.123672][ T14] Hardware name: QEMU KVM Virtual Machine, BIOS edk2-20250221-8.fc42 02/21/2025 [ 108.127458][ T14] Workqueue: iou_exit io_ring_exit_work [ 108.174205][ T14] Call trace: [ 108.175649][ T14] sanity_check_pinned_pages+0x7cc/0x7d0 (P) [ 108.178138][ T14] unpin_user_page+0x80/0x10c [ 108.180189][ T14] io_release_ubuf+0x84/0xf8 [ 108.182196][ T14] io_free_rsrc_node+0x250/0x57c [ 108.184345][ T14] io_rsrc_data_free+0x148/0x298 [ 108.186493][ T14] io_sqe_buffers_unregister+0x84/0xa0 [ 108.188991][ T14] io_ring_ctx_free+0x48/0x480 [ 108.191057][ T14] io_ring_exit_work+0x764/0x7d8 [ 108.193207][ T14] process_one_work+0x7e8/0x155c [ 108.195431][ T14] worker_thread+0x958/0xed8 [ 108.197561][ T14] kthread+0x5fc/0x75c [ 108.199362][ T14] ret_from_fork+0x10/0x20 We can pin a tail page of a folio, but then io_uring will try to unpin the head page of the folio. While it should be fine in terms of keeping the page actually alive, mm folks say it's wrong and triggers a debug warning. Use unpin_user_folio() instead of unpin_user_page*. Cc: stable@vger.kernel.org Debugged-by: David Hildenbrand <david@redhat.com> Reported-by: syzbot+1d335893772467199ab6@syzkaller.appspotmail.com Closes: https://lkml.kernel.org/r/683f1551.050a0220.55ceb.0017.GAE@google.com Fixes: a8edbb424b139 ("io_uring/rsrc: enable multi-hugepage buffer coalescing") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/io-uring/a28b0f87339ac2acf14a645dad1e95bbcbf18acd.1750771718.git.asml.silence@gmail.com/ [axboe: adapt to current tree, massage commit message] Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-06io_uring: fix potential page leak in io_sqe_buffer_register()Penglei Jiang
Commit e1c75831f682eef0f68b35723437146ed86070b1 upstream. If allocation of the 'imu' fails, then the existing pages aren't unpinned in the error path. This is mostly a theoretical issue, requiring fault injection to hit. Move unpin_user_pages() to unified error handling to fix the page leak issue. Fixes: d8c2237d0aa9 ("io_uring: add io_pin_pages() helper") Signed-off-by: Penglei Jiang <superman.xpt@gmail.com> Link: https://lore.kernel.org/r/20250617165644.79165-1-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/sqpoll: don't put task_struct on tctx setup failureJens Axboe
[ Upstream commit f2320f1dd6f6f82cb2c7aff23a12bab537bdea89 ] A recent commit moved the error handling of sqpoll thread and tctx failures into the thread itself, as part of fixing an issue. However, it missed that tctx allocation may also fail, and that io_sq_offload_create() does its own error handling for the task_struct in that case. Remove the manual task putting in io_sq_offload_create(), as io_sq_thread() will notice that the tctx did not get setup and hence it should put itself and exit. Reported-by: syzbot+763e12bbf004fb1062e4@syzkaller.appspotmail.com Fixes: ac0b8b327a56 ("io_uring: fix use-after-free of sq->thread in __io_uring_show_fdinfo()") 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 Jiang
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: don't truncate end buffer for multiple buffer peeksJens Axboe
commit 26ec15e4b0c1d7b25214d9c0be1d50492e2f006c upstream. If peeking a bunch of buffers, normally io_ring_buffers_peek() will truncate the end buffer. This isn't optimal as presumably more data will be arriving later, and hence it's better to stop with the last full buffer rather than truncate the end buffer. Cc: stable@vger.kernel.org Fixes: 35c8711c8fc4 ("io_uring/kbuf: add helpers for getting/peeking multiple buffers") 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>
2025-06-27io_uring/kbuf: account ring io_buffer_list memoryPavel Begunkov
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 Begunkov
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>
2025-06-19io_uring: consistently use rcu semantics with sqpoll threadKeith Busch
[ Upstream commit c538f400fae22725580842deb2bef546701b64bd ] The sqpoll thread is dereferenced with rcu read protection in one place, so it needs to be annotated as an __rcu type, and should consistently use rcu helpers for access and assignment to make sparse happy. Since most of the accesses occur under the sqd->lock, we can use rcu_dereference_protected() without declaring an rcu read section. Provide a simple helper to get the thread from a locked context. Fixes: ac0b8b327a5677d ("io_uring: fix use-after-free of sq->thread in __io_uring_show_fdinfo()") Signed-off-by: Keith Busch <kbusch@kernel.org> Link: https://lore.kernel.org/r/20250611205343.1821117-1-kbusch@meta.com [axboe: fold in fix for register.c] Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-19io_uring: fix use-after-free of sq->thread in __io_uring_show_fdinfo()Penglei Jiang
[ Upstream commit ac0b8b327a5677dc6fecdf353d808161525b1ff0 ] syzbot reports: BUG: KASAN: slab-use-after-free in getrusage+0x1109/0x1a60 Read of size 8 at addr ffff88810de2d2c8 by task a.out/304 CPU: 0 UID: 0 PID: 304 Comm: a.out Not tainted 6.16.0-rc1 #1 PREEMPT(voluntary) Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x53/0x70 print_report+0xd0/0x670 ? __pfx__raw_spin_lock_irqsave+0x10/0x10 ? getrusage+0x1109/0x1a60 kasan_report+0xce/0x100 ? getrusage+0x1109/0x1a60 getrusage+0x1109/0x1a60 ? __pfx_getrusage+0x10/0x10 __io_uring_show_fdinfo+0x9fe/0x1790 ? ksys_read+0xf7/0x1c0 ? do_syscall_64+0xa4/0x260 ? vsnprintf+0x591/0x1100 ? __pfx___io_uring_show_fdinfo+0x10/0x10 ? __pfx_vsnprintf+0x10/0x10 ? mutex_trylock+0xcf/0x130 ? __pfx_mutex_trylock+0x10/0x10 ? __pfx_show_fd_locks+0x10/0x10 ? io_uring_show_fdinfo+0x57/0x80 io_uring_show_fdinfo+0x57/0x80 seq_show+0x38c/0x690 seq_read_iter+0x3f7/0x1180 ? inode_set_ctime_current+0x160/0x4b0 seq_read+0x271/0x3e0 ? __pfx_seq_read+0x10/0x10 ? __pfx__raw_spin_lock+0x10/0x10 ? __mark_inode_dirty+0x402/0x810 ? selinux_file_permission+0x368/0x500 ? file_update_time+0x10f/0x160 vfs_read+0x177/0xa40 ? __pfx___handle_mm_fault+0x10/0x10 ? __pfx_vfs_read+0x10/0x10 ? mutex_lock+0x81/0xe0 ? __pfx_mutex_lock+0x10/0x10 ? fdget_pos+0x24d/0x4b0 ksys_read+0xf7/0x1c0 ? __pfx_ksys_read+0x10/0x10 ? do_user_addr_fault+0x43b/0x9c0 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0f74170fc9 Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 73 01 c3 48 8b 8 RSP: 002b:00007fffece049e8 EFLAGS: 00000206 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0f74170fc9 RDX: 0000000000001000 RSI: 00007fffece049f0 RDI: 0000000000000004 RBP: 00007fffece05ad0 R08: 0000000000000000 R09: 00007fffece04d90 R10: 0000000000000000 R11: 0000000000000206 R12: 00005651720a1100 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 </TASK> Allocated by task 298: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 __kasan_slab_alloc+0x6e/0x70 kmem_cache_alloc_node_noprof+0xe8/0x330 copy_process+0x376/0x5e00 create_io_thread+0xab/0xf0 io_sq_offload_create+0x9ed/0xf20 io_uring_setup+0x12b0/0x1cc0 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 22: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3b/0x60 __kasan_slab_free+0x37/0x50 kmem_cache_free+0xc4/0x360 rcu_core+0x5ff/0x19f0 handle_softirqs+0x18c/0x530 run_ksoftirqd+0x20/0x30 smpboot_thread_fn+0x287/0x6c0 kthread+0x30d/0x630 ret_from_fork+0xef/0x1a0 ret_from_fork_asm+0x1a/0x30 Last potentially related work creation: kasan_save_stack+0x33/0x60 kasan_record_aux_stack+0x8c/0xa0 __call_rcu_common.constprop.0+0x68/0x940 __schedule+0xff2/0x2930 __cond_resched+0x4c/0x80 mutex_lock+0x5c/0xe0 io_uring_del_tctx_node+0xe1/0x2b0 io_uring_clean_tctx+0xb7/0x160 io_uring_cancel_generic+0x34e/0x760 do_exit+0x240/0x2350 do_group_exit+0xab/0x220 __x64_sys_exit_group+0x39/0x40 x64_sys_call+0x1243/0x1840 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88810de2cb00 which belongs to the cache task_struct of size 3712 The buggy address is located 1992 bytes inside of freed 3712-byte region [ffff88810de2cb00, ffff88810de2d980) which is caused by the task_struct pointed to by sq->thread being released while it is being used in the function __io_uring_show_fdinfo(). Holding ctx->uring_lock does not prevent ehre relase or exit of sq->thread. Fix this by assigning and looking up ->thread under RCU, and grabbing a reference to the task_struct. This ensures that it cannot get released while fdinfo is using it. Reported-by: syzbot+531502bbbe51d2f769f4@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/682b06a5.a70a0220.3849cf.00b3.GAE@google.com Fixes: 3fcb9d17206e ("io_uring/sqpoll: statistics of the true utilization of sq threads") Signed-off-by: Penglei Jiang <superman.xpt@gmail.com> Link: https://lore.kernel.org/r/20250610171801.70960-1-superman.xpt@gmail.com [axboe: massage commit message] Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-29io_uring: fix overflow resched cqe reorderingPavel Begunkov
[ 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>
2025-05-29io_uring/fdinfo: annotate racy sq/cq head/tail readsJens Axboe
[ 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>
2025-05-29io_uring/msg: initialise msg request opcodePavel Begunkov
[ Upstream commit 9cc0bbdaba2a66ad90bc6ce45163b7745baffe98 ] It's risky to have msg request opcode set to garbage, so at least initialise it to nop. Later we might want to add a user inaccessible opcode for such cases. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/9afe650fcb348414a4529d89f52eb8969ba06efd.1743190078.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-29io_uring: don't duplicate flushing in io_req_post_cqePavel Begunkov
[ Upstream commit 5e16f1a68d28965c12b6fa227a306fef8a680f84 ] io_req_post_cqe() sets submit_state.cq_flush so that *flush_completions() can take care of batch commiting CQEs. Don't commit it twice by using __io_cq_unlock_post(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/41c416660c509cee676b6cad96081274bcb459f3.1745493861.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-18io_uring: always arm linked timeouts prior to issueJens Axboe
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>
2025-05-18io_uring/sqpoll: Increase task_work submission batch sizeGabriel Krisman Bertazi
[ Upstream commit 92835cebab120f8a5f023a26a792a2ac3f816c4f ] Our QA team reported a 10%-23%, throughput reduction on an io_uring sqpoll testcase doing IO to a null_blk, that I traced back to a reduction of the device submission queue depth utilization. It turns out that, after commit af5d68f8892f ("io_uring/sqpoll: manage task_work privately"), we capped the number of task_work entries that can be completed from a single spin of sqpoll to only 8 entries, before the sqpoll goes around to (potentially) sleep. While this cap doesn't drive the submission side directly, it impacts the completion behavior, which affects the number of IO queued by fio per sqpoll cycle on the submission side, and io_uring ends up seeing less ios per sqpoll cycle. As a result, block layer plugging is less effective, and we see more time spent inside the block layer in profilings charts, and increased submission latency measured by fio. There are other places that have increased overhead once sqpoll sleeps more often, such as the sqpoll utilization calculation. But, in this microbenchmark, those were not representative enough in perf charts, and their removal didn't yield measurable changes in throughput. The major overhead comes from the fact we plug less, and less often, when submitting to the block layer. My benchmark is: fio --ioengine=io_uring --direct=1 --iodepth=128 --runtime=300 --bs=4k \ --invalidate=1 --time_based --ramp_time=10 --group_reporting=1 \ --filename=/dev/nullb0 --name=RandomReads-direct-nullb-sqpoll-4k-1 \ --rw=randread --numjobs=1 --sqthread_poll In one machine, tested on top of Linux 6.15-rc1, we have the following baseline: READ: bw=4994MiB/s (5236MB/s), 4994MiB/s-4994MiB/s (5236MB/s-5236MB/s), io=439GiB (471GB), run=90001-90001msec With this patch: READ: bw=5762MiB/s (6042MB/s), 5762MiB/s-5762MiB/s (6042MB/s-6042MB/s), io=506GiB (544GB), run=90001-90001msec which is a 15% improvement in measured bandwidth. The average submission latency is noticeably lowered too. As measured by fio: Baseline: lat (usec): min=20, max=241, avg=99.81, stdev=3.38 Patched: lat (usec): min=26, max=226, avg=86.48, stdev=4.82 If we look at blktrace, we can also see the plugging behavior is improved. In the baseline, we end up limited to plugging 8 requests in the block layer regardless of the device queue depth size, while after patching we can drive more io, and we manage to utilize the full device queue. In the baseline, after a stabilization phase, an ordinary submission looks like: 254,0 1 49942 0.016028795 5977 U N [iou-sqp-5976] 7 After patching, I see consistently more requests per unplug. 254,0 1 4996 0.001432872 3145 U N [iou-sqp-3144] 32 Ideally, the cap size would at least be the deep enough to fill the device queue, but we can't predict that behavior, or assume all IO goes to a single device, and thus can't guess the ideal batch size. We also don't want to let the tw run unbounded, though I'm not sure it would really be a problem. Instead, let's just give it a more sensible value that will allow for more efficient batching. I've tested with different cap values, and initially proposed to increase the cap to 1024. Jens argued it is too big of a bump and I observed that, with 32, I'm no longer able to observe this bottleneck in any of my machines. Fixes: af5d68f8892f ("io_uring/sqpoll: manage task_work privately") Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de> Link: https://lore.kernel.org/r/20250508181203.3785544-1-krisman@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-18io_uring: ensure deferred completions are flushed for multishotJens Axboe
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, as new multishot completions get posted before the deferred ones are flushed. This can cause confusion on the application side, if strict ordering is required for the use case. 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>
2025-05-02io_uring: always do atomic put from iowqPavel Begunkov
[ 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 Axboe
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>
2025-04-25block: add a rq_list typeChristoph Hellwig
commit a3396b99990d8b4e5797e7b16fdeb64c15ae97bb upstream. Replace the semi-open coded request list helpers with a proper rq_list type that mirrors the bio_list and has head and tail pointers. Besides better type safety this actually allows to insert at the tail of the list, which will be useful soon. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20241113152050.157179-5-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-04-20io_uring/kbuf: reject zero sized provided buffersJens Axboe
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>
2025-04-20io_uring/net: fix io_req_post_cqe abuse by send bundlePavel Begunkov
commit 6889ae1b4df1579bcdffef023e2ea9a982565dff upstream. [ 114.987980][ T5313] WARNING: CPU: 6 PID: 5313 at io_uring/io_uring.c:872 io_req_post_cqe+0x12e/0x4f0 [ 114.991597][ T5313] RIP: 0010:io_req_post_cqe+0x12e/0x4f0 [ 115.001880][ T5313] Call Trace: [ 115.002222][ T5313] <TASK> [ 115.007813][ T5313] io_send+0x4fe/0x10f0 [ 115.009317][ T5313] io_issue_sqe+0x1a6/0x1740 [ 115.012094][ T5313] io_wq_submit_work+0x38b/0xed0 [ 115.013223][ T5313] io_worker_handle_work+0x62a/0x1600 [ 115.013876][ T5313] io_wq_worker+0x34f/0xdf0 As the comment states, io_req_post_cqe() should only be used by multishot requests, i.e. REQ_F_APOLL_MULTISHOT, which bundled sends are not. Add a flag signifying whether a request wants to post multiple CQEs. Eventually REQ_F_APOLL_MULTISHOT should imply the new flag, but that's left out for simplicity. Cc: stable@vger.kernel.org Fixes: a05d1f625c7aa ("io_uring/net: support bundles for send") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/8b611dbb54d1cd47a88681f5d38c84d0c02bc563.1743067183.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-04-20io_uring/net: fix accept multishot handlingPavel Begunkov
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>
2025-03-28io_uring/net: fix sendzc double notif flushPavel Begunkov
commit 67c007d6c12da3e456c005083696c20d4498ae72 upstream. refcount_t: underflow; use-after-free. WARNING: CPU: 0 PID: 5823 at lib/refcount.c:28 refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28 RIP: 0010:refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28 Call Trace: <TASK> io_notif_flush io_uring/notif.h:40 [inline] io_send_zc_cleanup+0x121/0x170 io_uring/net.c:1222 io_clean_op+0x58c/0x9a0 io_uring/io_uring.c:406 io_free_batch_list io_uring/io_uring.c:1429 [inline] __io_submit_flush_completions+0xc16/0xd20 io_uring/io_uring.c:1470 io_submit_flush_completions io_uring/io_uring.h:159 [inline] Before the blamed commit, sendzc relied on io_req_msg_cleanup() to clear REQ_F_NEED_CLEANUP, so after the following snippet the request will never hit the core io_uring cleanup path. io_notif_flush(); io_req_msg_cleanup(); The easiest fix is to null the notification. io_send_zc_cleanup() can still be called after, but it's tolerated. Reported-by: syzbot+cf285a028ffba71b2ef5@syzkaller.appspotmail.com Tested-by: syzbot+cf285a028ffba71b2ef5@syzkaller.appspotmail.com Fixes: cc34d8330e036 ("io_uring/net: don't clear REQ_F_NEED_CLEANUP unconditionally") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/e1306007458b8891c88c4f20c966a17595f766b0.1742643795.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-28io_uring/net: don't clear REQ_F_NEED_CLEANUP unconditionallyJens Axboe
commit cc34d8330e036b6bffa88db9ea537bae6b03948f upstream. io_req_msg_cleanup() relies on the fact that io_netmsg_recycle() will always fully recycle, but that may not be the case if the msg cache was already full. To ensure that normal cleanup always gets run, let io_netmsg_recycle() deal with clearing the relevant cleanup flags, as it knows exactly when that should be done. Cc: stable@vger.kernel.org Reported-by: David Wei <dw@davidwei.uk> Fixes: 75191341785e ("io_uring/net: add iovec recycling") 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 Shankar
[ 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>
2025-03-22futex: Pass in task to futex_queue()Jens Axboe
[ Upstream commit 5e0e02f0d7e52cfc8b1adfc778dd02181d8b47b4 ] futex_queue() -> __futex_queue() uses 'current' as the task to store in the struct futex_q->task field. This is fine for synchronous usage of the futex infrastructure, but it's not always correct when used by io_uring where the task doing the initial futex_queue() might not be available later on. This doesn't lead to any issues currently, as the io_uring side doesn't support PI futexes, but it does leave a potentially dangling pointer which is never a good idea. Have futex_queue() take a task_struct argument, and have the regular callers pass in 'current' for that. Meanwhile io_uring can just pass in NULL, as the task should never be used off that path. In theory req->tctx->task could be used here, but there's no point populating it with a task field that will never be used anyway. Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/22484a23-542c-4003-b721-400688a0d055@kernel.dk Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-07io_uring/net: save msg_control for compatPavel Begunkov
[ 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 Begunkov
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>
2025-02-27io_uring/rw: forbid multishot async readsPavel Begunkov
commit 67b0025d19f99fb9fbb8b62e6975553c183f3a16 upstream. At the moment we can't sanely handle queuing an async request from a multishot context, so disable them. It shouldn't matter as pollable files / socekts don't normally do async. Patching it in __io_read() is not the cleanest way, but it's simpler than other options, so let's fix it there and clean up on top. Cc: stable@vger.kernel.org Reported-by: chase xd <sl1589472800@gmail.com> 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/7d51732c125159d17db4fe16f51ec41b936973f8.1739919038.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 Begunkov
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>
2025-02-21io_uring/uring_cmd: remove dead req_has_async_data() checkJens Axboe
[ Upstream commit 0edf1283a9d1419a2095b4fcdd95c11ac00a191c ] Any uring_cmd always has async data allocated now, there's no reason to check and clear a cached copy of the SQE. Fixes: d10f19dff56e ("io_uring/uring_cmd: switch to always allocating async data") Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-21io_uring/waitid: don't abuse io_tw_statePavel Begunkov
[ Upstream commit 06521ac0485effdcc9c792cb0b40ed8e6f2f5fb8 ] struct io_tw_state is managed by core io_uring, and opcode handling code must never try to cheat and create their own instances, it's plain incorrect. io_waitid_complete() attempts exactly that outside of the task work context, and even though the ring is locked, there would be no one to reap the requests from the defer completion list. It only works now because luckily it's called before io_uring_try_cancel_uring_cmd(), which flushes completions. Fixes: f31ecf671ddc4 ("io_uring: add IORING_OP_WAITID support") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-17io_uring/net: don't retry connect operation on EPOLLERRJens Axboe
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 Begunkov
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 Axboe
[ 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>
2025-02-01io_uring/rsrc: require cloned buffers to share accounting contextsJann Horn
Commit 19d340a2988d4f3e673cded9dde405d727d7e248 upstream. When IORING_REGISTER_CLONE_BUFFERS is used to clone buffers from uring instance A to uring instance B, where A and B use different MMs for accounting, the accounting can go wrong: If uring instance A is closed before uring instance B, the pinned memory counters for uring instance B will be decremented, even though the pinned memory was originally accounted through uring instance A; so the MM of uring instance B can end up with negative locked memory. Cc: stable@vger.kernel.org Closes: https://lore.kernel.org/r/CAG48ez1zez4bdhmeGLEFxtbFADY4Czn3CV0u9d_TMcbvRA01bg@mail.gmail.com Fixes: 7cc2a6eadcd7 ("io_uring: add IORING_REGISTER_COPY_BUFFERS method") Signed-off-by: Jann Horn <jannh@google.com> Link: https://lore.kernel.org/r/20250114-uring-check-accounting-v1-1-42e4145aa743@google.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-01-17io_uring: don't touch sqd->thread off tw addPavel Begunkov
commit bd2703b42decebdcddf76e277ba76b4c4a142d73 upstream. With IORING_SETUP_SQPOLL all requests are created by the SQPOLL task, which means that req->task should always match sqd->thread. Since accesses to sqd->thread should be separately protected, use req->task in io_req_normal_work_add() instead. Note, in the eyes of io_req_normal_work_add(), the SQPOLL task struct is always pinned and alive, and sqd->thread can either be the task or NULL. It's only problematic if the compiler decides to reload the value after the null check, which is not so likely. Cc: stable@vger.kernel.org Cc: Bui Quang Minh <minhquangbui99@gmail.com> Reported-by: lizetao <lizetao1@huawei.com> Fixes: 78f9b61bd8e54 ("io_uring: wake SQPOLL task when task_work is added to an empty queue") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/1cbbe72cf32c45a8fee96026463024cd8564a7d7.1736541357.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-01-17io_uring/eventfd: ensure io_eventfd_signal() defers another RCU periodJens Axboe
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/sqpoll: zero sqd->thread on tctx errorsPavel Begunkov
commit 4b7cfa8b6c28a9fa22b86894166a1a34f6d630ba upstream. Syzkeller reports: BUG: KASAN: slab-use-after-free in thread_group_cputime+0x409/0x700 kernel/sched/cputime.c:341 Read of size 8 at addr ffff88803578c510 by task syz.2.3223/27552 Call Trace: <TASK> ... kasan_report+0x143/0x180 mm/kasan/report.c:602 thread_group_cputime+0x409/0x700 kernel/sched/cputime.c:341 thread_group_cputime_adjusted+0xa6/0x340 kernel/sched/cputime.c:639 getrusage+0x1000/0x1340 kernel/sys.c:1863 io_uring_show_fdinfo+0xdfe/0x1770 io_uring/fdinfo.c:197 seq_show+0x608/0x770 fs/proc/fd.c:68 ... That's due to sqd->task not being cleared properly in cases where SQPOLL task tctx setup fails, which can essentially only happen with fault injection to insert allocation errors. Cc: stable@vger.kernel.org Fixes: 1251d2025c3e1 ("io_uring/sqpoll: early exit thread if task_context wasn't allocated") Reported-by: syzbot+3d92cfcfa84070b0a470@syzkaller.appspotmail.com Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/efc7ec7010784463b2e7466d7b5c02c2cb381635.1736519461.git.asml.silence@gmail.com 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 Begunkov
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>
2025-01-09io_uring/rw: fix downgraded mshot readPavel Begunkov
commit 38fc96a58ce40257aec79b32e9b310c86907c63c upstream. The io-wq path can downgrade a multishot request to oneshot mode, however io_read_mshot() doesn't handle that and would still post multiple CQEs. That's not allowed, because io_req_post_cqe() requires stricter context requirements. The described can only happen with pollable files that don't support FMODE_NOWAIT, which is an odd combination, so if even allowed it should be fairly rare. Cc: stable@vger.kernel.org Reported-by: chase xd <sl1589472800@gmail.com> Fixes: bee1d5becdf5b ("io_uring: disable io-wq execution of multishot NOWAIT requests") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/c5c8c4a50a882fd581257b81bf52eee260ac29fd.1735407848.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>