kernel/git/stable/linux.git/fs/io_uring.c, branch linux-5.17.y

io_uring: only wake when the correct events are set

2022-06-09T08:25:53+00:00

[ Upstream commit 1b1d7b4bf1d9948c8dba5ee550459ce7c65ac019 ] The check for waking up a request compares the poll_t bits, however this will always contain some common flags so this always wakes up. For files with single wait queues such as sockets this can cause the request to be sent to the async worker unnecesarily. Further if it is non-blocking will complete the request with EAGAIN which is not desired. Here exclude these common events, making sure to not exclude POLLERR which might be important. Fixes: d7718a9d25a6 ("io_uring: use poll driven retry for files that support it") Signed-off-by: Dylan Yudaken Link: https://lore.kernel.org/r/20220512091834.728610-3-dylany@fb.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring: fix assuming triggered poll waitqueue is the single poll

2022-06-09T08:25:53+00:00

[ Upstream commit d89a4fac0fbc6fe5fc24d1c9a889440dcf410368 ] syzbot reports a recent regression: BUG: KASAN: use-after-free in __wake_up_common+0x637/0x650 kernel/sched/wait.c:101 Read of size 8 at addr ffff888011e8a130 by task syz-executor413/3618 CPU: 0 PID: 3618 Comm: syz-executor413 Tainted: G W 5.17.0-syzkaller-01402-g8565d64430f8 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0x8d/0x303 mm/kasan/report.c:255 __kasan_report mm/kasan/report.c:442 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:459 __wake_up_common+0x637/0x650 kernel/sched/wait.c:101 __wake_up_common_lock+0xd0/0x130 kernel/sched/wait.c:138 tty_release+0x657/0x1200 drivers/tty/tty_io.c:1781 __fput+0x286/0x9f0 fs/file_table.c:317 task_work_run+0xdd/0x1a0 kernel/task_work.c:164 exit_task_work include/linux/task_work.h:32 [inline] do_exit+0xaff/0x29d0 kernel/exit.c:806 do_group_exit+0xd2/0x2f0 kernel/exit.c:936 __do_sys_exit_group kernel/exit.c:947 [inline] __se_sys_exit_group kernel/exit.c:945 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:945 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f439a1fac69 which is due to leaving the request on the waitqueue mistakenly. The reproducer is using a tty device, which means we end up arming the same poll queue twice (it uses the same poll waitqueue for both), but in io_poll_wake() we always just clear REQ_F_SINGLE_POLL regardless of which entry triggered. This leaves one waitqueue potentially armed after we're done, which then blows up in tty when the waitqueue is attempted removed. We have no room to store this information, so simply encode it in the wait_queue_entry->private where we store the io_kiocb request pointer. Fixes: 91eac1c69c20 ("io_uring: cache poll/double-poll state with a request flag") Reported-by: syzbot+09ad4050dd3a120bfccd@syzkaller.appspotmail.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring: cache poll/double-poll state with a request flag

2022-06-09T08:25:53+00:00

[ Upstream commit 91eac1c69c202d9dad8bf717ae5b92db70bfe5cf ] With commit "io_uring: cache req->apoll->events in req->cflags" applied, we now have just io_poll_remove_entries() dipping into req->apoll when it isn't strictly necessary. Mark poll and double-poll with a flag, so we know if we need to look at apoll->double_poll. This avoids pulling in those cachelines if we don't need them. The common case is that the poll wake handler already removed these entries while hot off the completion path. Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring: avoid io-wq -EAGAIN looping for !IOPOLL

2022-06-09T08:25:52+00:00

[ Upstream commit e0deb6a025ae8c850dc8685be39fb27b06c88736 ] If an opcode handler semi-reliably returns -EAGAIN, io_wq_submit_work() might continue busily hammer the same handler over and over again, which is not ideal. The -EAGAIN handling in question was put there only for IOPOLL, so restrict it to IOPOLL mode only where there is no other recourse than to retry as we cannot wait. Fixes: def596e9557c9 ("io_uring: support for IO polling") Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/f168b4f24181942f3614dd8ff648221736f572e6.1652433740.git.asml.silence@gmail.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring: assign non-fixed early for async work

2022-05-18T08:28:17+00:00

[ Upstream commit a196c78b5443fc61af2c0490213b9d125482cbd1 ] We defer file assignment to ensure that fixed files work with links between a direct accept/open and the links that follow it. But this has the side effect that normal file assignment is then not complete by the time that request submission has been done. For deferred execution, if the file is a regular file, assign it when we do the async prep anyway. Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring: fix uninitialized field in rw io_kiocb

2022-05-09T07:16:26+00:00

[ Upstream commit 32452a3eb8b64e01e2be717f518c0be046975b9d ] io_rw_init_file does not initialize kiocb->private, so when iocb_bio_iopoll reads kiocb->private it can contain uninitialized data. Fixes: 3e08773c3841 ("block: switch polling to be bio based") Signed-off-by: Joseph Ravichandran Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring: check reserved fields for recv/recvmsg

2022-05-09T07:16:25+00:00

[ Upstream commit 5a1e99b61b0c81388cde0c808b3e4173907df19f ] We should check unused fields for non-zero and -EINVAL if they are set, making it consistent with other opcodes. Fixes: aa1fa28fc73e ("io_uring: add support for recvmsg()") Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring: check reserved fields for send/sendmsg

2022-05-09T07:16:25+00:00

[ Upstream commit 588faa1ea5eecb351100ee5d187b9be99210f70d ] We should check unused fields for non-zero and -EINVAL if they are set, making it consistent with other opcodes. Fixes: 0fa03c624d8f ("io_uring: add support for sendmsg()") Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring: fix leaks on IOPOLL and CQE_SKIP

2022-04-27T12:41:17+00:00

commit c0713540f6d55c53dca65baaead55a5a8b20552d upstream. If all completed requests in io_do_iopoll() were marked with REQ_F_CQE_SKIP, we'll not only skip CQE posting but also io_free_batch_list() leaking memory and resources. Move @nr_events increment before REQ_F_CQE_SKIP check. We'll potentially return the value greater than the real one, but iopolling will deal with it and the userspace will re-iopoll if needed. In anyway, I don't think there are many use cases for REQ_F_CQE_SKIP + IOPOLL. Fixes: 83a13a4181b0e ("io_uring: tweak iopoll CQE_SKIP event counting") Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/5072fc8693fbfd595f89e5d4305bfcfd5d2f0a64.1650186611.git.asml.silence@gmail.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring: free iovec if file assignment fails

2022-04-27T12:41:12+00:00

[ Upstream commit 323b190ba2debbcc03c01d2edaf1ec6b43e6ae43 ] We just return failure in this case, but we need to release the iovec first. If we're doing IO with more than FAST_IOV segments, then the iovec is allocated and must be freed. Reported-by: syzbot+96b43810dfe9c3bb95ed@syzkaller.appspotmail.com Fixes: 584b0180f0f4 ("io_uring: move read/write file prep state into actual opcode handler") Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin