kernel/linux.git, branch v5.15.11

Linux 5.15.11

2021-12-22T08:32:52+00:00

Link: https://lore.kernel.org/r/20211220143040.058287525@linuxfoundation.org Tested-by: Jon Hunter Tested-by: Shuah Khan Tested-by: Ronald Warsow Tested-by: Salvatore Bonaccorso Tested-by: Linux Kernel Functional Testing Tested-by: Rudi Heitbaum Tested-by: Florian Fainelli Tested-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman

xen/netback: don't queue unlimited number of packages

2021-12-22T08:32:52+00:00

commit be81992f9086b230623ae3ebbc85ecee4d00a3d3 upstream. In case a guest isn't consuming incoming network traffic as fast as it is coming in, xen-netback is buffering network packages in unlimited numbers today. This can result in host OOM situations. Commit f48da8b14d04ca8 ("xen-netback: fix unlimited guest Rx internal queue and carrier flapping") meant to introduce a mechanism to limit the amount of buffered data by stopping the Tx queue when reaching the data limit, but this doesn't work for cases like UDP. When hitting the limit don't queue further SKBs, but drop them instead. In order to be able to tell Rx packages have been dropped increment the rx_dropped statistics counter in this case. It should be noted that the old solution to continue queueing SKBs had the additional problem of an overflow of the 32-bit rx_queue_len value would result in intermittent Tx queue enabling. This is part of XSA-392 Fixes: f48da8b14d04ca8 ("xen-netback: fix unlimited guest Rx internal queue and carrier flapping") Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Greg Kroah-Hartman

xen/netback: fix rx queue stall detection

2021-12-22T08:32:52+00:00

commit 6032046ec4b70176d247a71836186d47b25d1684 upstream. Commit 1d5d48523900a4b ("xen-netback: require fewer guest Rx slots when not using GSO") introduced a security problem in netback, as an interface would only be regarded to be stalled if no slot is available in the rx queue ring page. In case the SKB at the head of the queued requests will need more than one rx slot and only one slot is free the stall detection logic will never trigger, as the test for that is only looking for at least one slot to be free. Fix that by testing for the needed number of slots instead of only one slot being available. In order to not have to take the rx queue lock that often, store the number of needed slots in the queue data. As all SKB dequeue operations happen in the rx queue kernel thread this is safe, as long as the number of needed slots is accessed via READ/WRITE_ONCE() only and updates are always done with the rx queue lock held. Add a small helper for obtaining the number of free slots. This is part of XSA-392 Fixes: 1d5d48523900a4b ("xen-netback: require fewer guest Rx slots when not using GSO") Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Greg Kroah-Hartman

xen/console: harden hvc_xen against event channel storms

2021-12-22T08:32:52+00:00

commit fe415186b43df0db1f17fa3a46275fd92107fe71 upstream. The Xen console driver is still vulnerable for an attack via excessive number of events sent by the backend. Fix that by using a lateeoi event channel. For the normal domU initial console this requires the introduction of bind_evtchn_to_irq_lateeoi() as there is no xenbus device available at the time the event channel is bound to the irq. As the decision whether an interrupt was spurious or not requires to test for bytes having been read from the backend, move sending the event into the if statement, as sending an event without having found any bytes to be read is making no sense at all. This is part of XSA-391 Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Greg Kroah-Hartman

xen/netfront: harden netfront against event channel storms

2021-12-22T08:32:51+00:00

commit b27d47950e481f292c0a5ad57357edb9d95d03ba upstream. The Xen netfront driver is still vulnerable for an attack via excessive number of events sent by the backend. Fix that by using lateeoi event channels. For being able to detect the case of no rx responses being added while the carrier is down a new lock is needed in order to update and test rsp_cons and the number of seen unconsumed responses atomically. This is part of XSA-391 Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Greg Kroah-Hartman

xen/blkfront: harden blkfront against event channel storms

2021-12-22T08:32:51+00:00

commit 0fd08a34e8e3b67ec9bd8287ac0facf8374b844a upstream. The Xen blkfront driver is still vulnerable for an attack via excessive number of events sent by the backend. Fix that by using lateeoi event channels. This is part of XSA-391 Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Greg Kroah-Hartman

Revert "xsk: Do not sleep in poll() when need_wakeup set"

2021-12-22T08:32:51+00:00

commit 0706a78f31c4217ca144f630063ec9561a21548d upstream. This reverts commit bd0687c18e635b63233dc87f38058cd728802ab4. This patch causes a Tx only workload to go to sleep even when it does not have to, leading to misserable performance in skb mode. It fixed one rare problem but created a much worse one, so this need to be reverted while I try to craft a proper solution to the original problem. Fixes: bd0687c18e63 ("xsk: Do not sleep in poll() when need_wakeup set") Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20211217145646.26449-1-magnus.karlsson@gmail.com Signed-off-by: Greg Kroah-Hartman

selftests/damon: test debugfs file reads/writes with huge count

2021-12-22T08:32:51+00:00

commit b4a002889d24979295ed3c2bf1d5fcfb3901026a upstream. DAMON debugfs interface users were able to trigger warning by writing some files with arbitrarily large 'count' parameter. The issue is fixed with commit db7a347b26fe ("mm/damon/dbgfs: use '__GFP_NOWARN' for user-specified size buffer allocation"). This commit adds a test case for the issue in DAMON selftests to avoid future regressions. Link: https://lkml.kernel.org/r/20211201150440.1088-11-sj@kernel.org Signed-off-by: SeongJae Park Cc: Brendan Higgins Cc: Shuah Khan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

bus: ti-sysc: Fix variable set but not used warning for reinit_modules

2021-12-22T08:32:51+00:00

commit 1b1da99b845337362a3dafe0f7b49927ab4ae041 upstream. Fix drivers/bus/ti-sysc.c:2494:13: error: variable 'error' set but not used introduced by commit 9d881361206e ("bus: ti-sysc: Add quirk handling for reinit on context lost"). Reported-by: kernel test robot Signed-off-by: Tony Lindgren Signed-off-by: Greg Kroah-Hartman

io-wq: drop wqe lock before creating new worker

2021-12-22T08:32:51+00:00

commit d800c65c2d4eccebb27ffb7808e842d5b533823c upstream. We have two io-wq creation paths: - On queue enqueue - When a worker goes to sleep The latter invokes worker creation with the wqe->lock held, but that can run into problems if we end up exiting and need to cancel the queued work. syzbot caught this: ============================================ WARNING: possible recursive locking detected 5.16.0-rc4-syzkaller #0 Not tainted -------------------------------------------- iou-wrk-6468/6471 is trying to acquire lock: ffff88801aa98018 (&wqe->lock){+.+.}-{2:2}, at: io_worker_cancel_cb+0xb7/0x210 fs/io-wq.c:187 but task is already holding lock: ffff88801aa98018 (&wqe->lock){+.+.}-{2:2}, at: io_wq_worker_sleeping+0xb6/0x140 fs/io-wq.c:700 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&wqe->lock); lock(&wqe->lock); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by iou-wrk-6468/6471: #0: ffff88801aa98018 (&wqe->lock){+.+.}-{2:2}, at: io_wq_worker_sleeping+0xb6/0x140 fs/io-wq.c:700 stack backtrace: CPU: 1 PID: 6471 Comm: iou-wrk-6468 Not tainted 5.16.0-rc4-syzkaller #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+0x1dc/0x2d8 lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2956 [inline] check_deadlock kernel/locking/lockdep.c:2999 [inline] validate_chain+0x5984/0x8240 kernel/locking/lockdep.c:3788 __lock_acquire+0x1382/0x2b00 kernel/locking/lockdep.c:5027 lock_acquire+0x19f/0x4d0 kernel/locking/lockdep.c:5637 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 io_worker_cancel_cb+0xb7/0x210 fs/io-wq.c:187 io_wq_cancel_tw_create fs/io-wq.c:1220 [inline] io_queue_worker_create+0x3cf/0x4c0 fs/io-wq.c:372 io_wq_worker_sleeping+0xbe/0x140 fs/io-wq.c:701 sched_submit_work kernel/sched/core.c:6295 [inline] schedule+0x67/0x1f0 kernel/sched/core.c:6323 schedule_timeout+0xac/0x300 kernel/time/timer.c:1857 wait_woken+0xca/0x1b0 kernel/sched/wait.c:460 unix_msg_wait_data net/unix/unix_bpf.c:32 [inline] unix_bpf_recvmsg+0x7f9/0xe20 net/unix/unix_bpf.c:77 unix_stream_recvmsg+0x214/0x2c0 net/unix/af_unix.c:2832 sock_recvmsg_nosec net/socket.c:944 [inline] sock_recvmsg net/socket.c:962 [inline] sock_read_iter+0x3a7/0x4d0 net/socket.c:1035 call_read_iter include/linux/fs.h:2156 [inline] io_iter_do_read fs/io_uring.c:3501 [inline] io_read fs/io_uring.c:3558 [inline] io_issue_sqe+0x144c/0x9590 fs/io_uring.c:6671 io_wq_submit_work+0x2d8/0x790 fs/io_uring.c:6836 io_worker_handle_work+0x808/0xdd0 fs/io-wq.c:574 io_wqe_worker+0x395/0x870 fs/io-wq.c:630 ret_from_fork+0x1f/0x30 We can safely drop the lock before doing work creation, making the two contexts the same in that regard. Reported-by: syzbot+b18b8be69df33a3918e9@syzkaller.appspotmail.com Fixes: 71a85387546e ("io-wq: check for wq exit after adding new worker task_work") Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman