[ Upstream commit 2bec445f9bf35e52e395b971df48d3e1e5dc704a ]

Latest commit 853697504de0 ("tcp: Fix highest_sack and highest_sack_seq")
apparently allowed syzbot to trigger various crashes in TCP stack [1]

I believe this commit only made things easier for syzbot to find
its way into triggering use-after-frees. But really the bugs
could lead to bad TCP behavior or even plain crashes even for
non malicious peers.

I have audited all calls to tcp_rtx_queue_unlink() and
tcp_rtx_queue_unlink_and_free() and made sure tp->highest_sack would be updated
if we are removing from rtx queue the skb that tp->highest_sack points to.

These updates were missing in three locations :

1) tcp_clean_rtx_queue() [This one seems quite serious,
                          I have no idea why this was not caught earlier]

2) tcp_rtx_queue_purge() [Probably not a big deal for normal operations]

3) tcp_send_synack()     [Probably not a big deal for normal operations]

[1]
BUG: KASAN: use-after-free in tcp_highest_sack_seq include/net/tcp.h:1864 [inline]
BUG: KASAN: use-after-free in tcp_highest_sack_seq include/net/tcp.h:1856 [inline]
BUG: KASAN: use-after-free in tcp_check_sack_reordering+0x33c/0x3a0 net/ipv4/tcp_input.c:891
Read of size 4 at addr ffff8880a488d068 by task ksoftirqd/1/16

CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.5.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
 __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:639
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:134
 tcp_highest_sack_seq include/net/tcp.h:1864 [inline]
 tcp_highest_sack_seq include/net/tcp.h:1856 [inline]
 tcp_check_sack_reordering+0x33c/0x3a0 net/ipv4/tcp_input.c:891
 tcp_try_undo_partial net/ipv4/tcp_input.c:2730 [inline]
 tcp_fastretrans_alert+0xf74/0x23f0 net/ipv4/tcp_input.c:2847
 tcp_ack+0x2577/0x5bf0 net/ipv4/tcp_input.c:3710
 tcp_rcv_established+0x6dd/0x1e90 net/ipv4/tcp_input.c:5706
 tcp_v4_do_rcv+0x619/0x8d0 net/ipv4/tcp_ipv4.c:1619
 tcp_v4_rcv+0x307f/0x3b40 net/ipv4/tcp_ipv4.c:2001
 ip_protocol_deliver_rcu+0x5a/0x880 net/ipv4/ip_input.c:204
 ip_local_deliver_finish+0x23b/0x380 net/ipv4/ip_input.c:231
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ip_local_deliver+0x1e9/0x520 net/ipv4/ip_input.c:252
 dst_input include/net/dst.h:442 [inline]
 ip_rcv_finish+0x1db/0x2f0 net/ipv4/ip_input.c:428
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ip_rcv+0xe8/0x3f0 net/ipv4/ip_input.c:538
 __netif_receive_skb_one_core+0x113/0x1a0 net/core/dev.c:5148
 __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5262
 process_backlog+0x206/0x750 net/core/dev.c:6093
 napi_poll net/core/dev.c:6530 [inline]
 net_rx_action+0x508/0x1120 net/core/dev.c:6598
 __do_softirq+0x262/0x98c kernel/softirq.c:292
 run_ksoftirqd kernel/softirq.c:603 [inline]
 run_ksoftirqd+0x8e/0x110 kernel/softirq.c:595
 smpboot_thread_fn+0x6a3/0xa40 kernel/smpboot.c:165
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 10091:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:521
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc_node mm/slab.c:3263 [inline]
 kmem_cache_alloc_node+0x138/0x740 mm/slab.c:3575
 __alloc_skb+0xd5/0x5e0 net/core/skbuff.c:198
 alloc_skb_fclone include/linux/skbuff.h:1099 [inline]
 sk_stream_alloc_skb net/ipv4/tcp.c:875 [inline]
 sk_stream_alloc_skb+0x113/0xc90 net/ipv4/tcp.c:852
 tcp_sendmsg_locked+0xcf9/0x3470 net/ipv4/tcp.c:1282
 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1432
 inet_sendmsg+0x9e/0xe0 net/ipv4/af_inet.c:807
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:672
 __sys_sendto+0x262/0x380 net/socket.c:1998
 __do_sys_sendto net/socket.c:2010 [inline]
 __se_sys_sendto net/socket.c:2006 [inline]
 __x64_sys_sendto+0xe1/0x1a0 net/socket.c:2006
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 10095:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:335 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:474
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:483
 __cache_free mm/slab.c:3426 [inline]
 kmem_cache_free+0x86/0x320 mm/slab.c:3694
 kfree_skbmem+0x178/0x1c0 net/core/skbuff.c:645
 __kfree_skb+0x1e/0x30 net/core/skbuff.c:681
 sk_eat_skb include/net/sock.h:2453 [inline]
 tcp_recvmsg+0x1252/0x2930 net/ipv4/tcp.c:2166
 inet_recvmsg+0x136/0x610 net/ipv4/af_inet.c:838
 sock_recvmsg_nosec net/socket.c:886 [inline]
 sock_recvmsg net/socket.c:904 [inline]
 sock_recvmsg+0xce/0x110 net/socket.c:900
 __sys_recvfrom+0x1ff/0x350 net/socket.c:2055
 __do_sys_recvfrom net/socket.c:2073 [inline]
 __se_sys_recvfrom net/socket.c:2069 [inline]
 __x64_sys_recvfrom+0xe1/0x1a0 net/socket.c:2069
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880a488d040
 which belongs to the cache skbuff_fclone_cache of size 456
The buggy address is located 40 bytes inside of
 456-byte region [ffff8880a488d040, ffff8880a488d208)
The buggy address belongs to the page:
page:ffffea0002922340 refcount:1 mapcount:0 mapping:ffff88821b057000 index:0x0
raw: 00fffe0000000200 ffffea00022a5788 ffffea0002624a48 ffff88821b057000
raw: 0000000000000000 ffff8880a488d040 0000000100000006 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a488cf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a488cf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880a488d000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                                          ^
 ffff8880a488d080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a488d100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

Fixes: 853697504de0 ("tcp: Fix highest_sack and highest_sack_seq")
Fixes: 50895b9d ("tcp: highest_sack fix")
Fixes: 737ff314 ("tcp: use sequence distance to detect reordering")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Cambda Zhu <cambda@linux.alibaba.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Acked-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NTony Lu <tonylu@linux.alibaba.com>
Acked-by: NDust Li <dust.li@linux.alibaba.com>

commit 94e297c50b529f5d01cfd1dbc808d61e95180ab7 upstream.

ctags indexing ("make tags" command) throws this warning:

    ctags: Warning: include/linux/notifier.h:125:
    null expansion of name pattern "\1"

This is the result of DEFINE_PER_CPU() macro expansion.  Fix that by
getting rid of line break.

Similar fix was already done in commit 25528213 ("tags: Fix
DEFINE_PER_CPU expansions"), but this one probably wasn't noticed.

Link: http://lkml.kernel.org/r/20181030202808.28027-1-semen.protsenko@linaro.org
Fixes: 9c80172b ("kernel/SRCU: provide a static initializer")
Signed-off-by: NSam Protsenko <semen.protsenko@linaro.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NCambda Zhu <cambda@linux.alibaba.com>
Acked-by: NXunlei Pang <xlpang@linux.alibaba.com>

To fix the following build warning:
mm/memcontrol.c: In function ‘mem_cgroup_move_account’:
mm/memcontrol.c:5604:6: warning: unused variable ‘nid’ [-Wunused-variable]
  int nid = page_to_nid(page);
      ^

Fixes: 96298509 ("mm: thp: don't need care deferred split queue in memcg charge move path")
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Acked-by: NYang Shi <yang.shi@linux.alibaba.com>

commit fac0516b5534897bf4c4a88daa06a8cfa5611b23 upstream

If compound is true, this means it is a PMD mapped THP.  Which implies
the page is not linked to any defer list.  So the first code chunk will
not be executed.

Also with this reason, it would not be proper to add this page to a
defer list.  So the second code chunk is not correct.

Based on this, we should remove the defer list related code.

[yang.shi@linux.alibaba.com: better patch title]
Link: http://lkml.kernel.org/r/20200117233836.3434-1-richardw.yang@linux.intel.com
Fixes: 87eaceb3faa5 ("mm: thp: make deferred split shrinker memcg aware")
Signed-off-by: NWei Yang <richardw.yang@linux.intel.com>
Suggested-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: NYang Shi <yang.shi@linux.alibaba.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: <stable@vger.kernel.org>    [5.4+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
[Fixed conflicts with our 4.19 kernel]
Signed-off-by: NYang Shi <yang.shi@linux.alibaba.com>
Acked-by: NJoseph Qi <joseph.qi@linux.alibaba.com>

commit 08f5439f1df25a6cf6cf4c72cf6c13025599ce67 upstream.

The outer poll loop checks for whether we need to reschedule, and
returns to userspace if we do. However, it's possible to get stuck
in the inner loop as well, if the CPU we are running on needs to
reschedule to finish the IO work.

Add the need_resched() check in the inner loop as well. This fixes
a potential hang if the kernel is configured with
CONFIG_PREEMPT_VOLUNTARY=y.
Reported-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Tested-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit a3a0e43fd77013819e4b6f55e37e0efe8e35d805 upstream.

We need to check if we have CQEs pending before starting a poll loop,
as those could be the events we will be spinning for (and hence we'll
find none). This can happen if a CQE triggers an error, or if it is
found by eg an IRQ before we get a chance to find it through polling.
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit 500f9fbadef86466a435726192f4ca4df7d94236 upstream.

If a request issue ends up being punted to async context to avoid
blocking, we can get into a situation where the original application
enters the poll loop for that very request before it has been issued.
This should not be an issue, except that the polling will hold the
io_uring uring_ctx mutex for the duration of the poll. When the async
worker has actually issued the request, it needs to acquire this mutex
to add the request to the poll issued list. Since the application
polling is already holding this mutex, the workqueue sleeps on the
mutex forever, and the application thus never gets a chance to poll for
the very request it was interested in.

Fix this by ensuring that the polling drops the uring_ctx occasionally
if it's not making any progress.
Reported-by: NJeffrey M. Birnbaum <jmbnyc@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit a982eeb09b6030e567b8b815277c8c9197168040 upstream.

This patch may fix two issues:

First, when IOSQE_IO_DRAIN set, the next IOs need to be inserted into
defer list to delay execution, but link io will be actively scheduled to
run by calling io_queue_sqe.

Second, when multiple LINK_IOs are inserted together with defer_list,
the LINK_IO is no longer keep order.

   |-------------|
   |   LINK_IO   |      ----> insert to defer_list  -----------
   |-------------|                                            |
   |   LINK_IO   |      ----> insert to defer_list  ----------|
   |-------------|                                            |
   |   LINK_IO   |      ----> insert to defer_list  ----------|
   |-------------|                                            |
   |   NORMAL_IO |      ----> insert to defer_list  ----------|
   |-------------|                                            |
                                                              |
                              queue_work at same time   <-----|

Fixes: 9e645e1105c ("io_uring: add support for sqe links")
Signed-off-by: NJackie Liu <liuyun01@kylinos.cn>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit 99c79f6692ccdc42e04deea8a36e22bb48168a62 upstream.

Commit bd11b3a391e3 ("io_uring: don't use iov_iter_advance() for fixed
buffers") introduced an optimization to avoid using the slow
iov_iter_advance by manually populating the iov_iter iterator in some
cases.

However, the computation of the iterator count field was erroneous: The
first bvec was always accounted for an extent of page size even if the
bvec length was smaller.

In consequence, some I/O operations on fixed buffers were unable to
operate on the full extent of the buffer, consistently skipping some
bytes at the end of it.

Fixes: bd11b3a391e3 ("io_uring: don't use iov_iter_advance() for fixed buffers")
Cc: stable@vger.kernel.org
Signed-off-by: NAleix Roca Nonell <aleix.rocanonell@bsc.es>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit d0ee879187df966ef638031b5f5183078d672141 upstream.

[root@localhost ~]# ./liburing/test/link

QEMU Standard PC report that:

[   29.379892] CPU: 0 PID: 84 Comm: kworker/u2:2 Not tainted 5.3.0-rc2-00051-g4010b622f1d2-dirty #86
[   29.379902] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
[   29.379913] Workqueue: io_ring-wq io_sq_wq_submit_work
[   29.379929] Call Trace:
[   29.379953]  dump_stack+0xa9/0x10e
[   29.379970]  ? io_sq_wq_submit_work+0xbf4/0xe90
[   29.379986]  print_address_description.cold.6+0x9/0x317
[   29.379999]  ? io_sq_wq_submit_work+0xbf4/0xe90
[   29.380010]  ? io_sq_wq_submit_work+0xbf4/0xe90
[   29.380026]  __kasan_report.cold.7+0x1a/0x34
[   29.380044]  ? io_sq_wq_submit_work+0xbf4/0xe90
[   29.380061]  kasan_report+0xe/0x12
[   29.380076]  io_sq_wq_submit_work+0xbf4/0xe90
[   29.380104]  ? io_sq_thread+0xaf0/0xaf0
[   29.380152]  process_one_work+0xb59/0x19e0
[   29.380184]  ? pwq_dec_nr_in_flight+0x2c0/0x2c0
[   29.380221]  worker_thread+0x8c/0xf40
[   29.380248]  ? __kthread_parkme+0xab/0x110
[   29.380265]  ? process_one_work+0x19e0/0x19e0
[   29.380278]  kthread+0x30b/0x3d0
[   29.380292]  ? kthread_create_on_node+0xe0/0xe0
[   29.380311]  ret_from_fork+0x3a/0x50

[   29.380635] Allocated by task 209:
[   29.381255]  save_stack+0x19/0x80
[   29.381268]  __kasan_kmalloc.constprop.6+0xc1/0xd0
[   29.381279]  kmem_cache_alloc+0xc0/0x240
[   29.381289]  io_submit_sqe+0x11bc/0x1c70
[   29.381300]  io_ring_submit+0x174/0x3c0
[   29.381311]  __x64_sys_io_uring_enter+0x601/0x780
[   29.381322]  do_syscall_64+0x9f/0x4d0
[   29.381336]  entry_SYSCALL_64_after_hwframe+0x49/0xbe

[   29.381633] Freed by task 84:
[   29.382186]  save_stack+0x19/0x80
[   29.382198]  __kasan_slab_free+0x11d/0x160
[   29.382210]  kmem_cache_free+0x8c/0x2f0
[   29.382220]  io_put_req+0x22/0x30
[   29.382230]  io_sq_wq_submit_work+0x28b/0xe90
[   29.382241]  process_one_work+0xb59/0x19e0
[   29.382251]  worker_thread+0x8c/0xf40
[   29.382262]  kthread+0x30b/0x3d0
[   29.382272]  ret_from_fork+0x3a/0x50

[   29.382569] The buggy address belongs to the object at ffff888067172140
                which belongs to the cache io_kiocb of size 224
[   29.384692] The buggy address is located 120 bytes inside of
                224-byte region [ffff888067172140, ffff888067172220)
[   29.386723] The buggy address belongs to the page:
[   29.387575] page:ffffea00019c5c80 refcount:1 mapcount:0 mapping:ffff88806ace5180 index:0x0
[   29.387587] flags: 0x100000000000200(slab)
[   29.387603] raw: 0100000000000200 dead000000000100 dead000000000122 ffff88806ace5180
[   29.387617] raw: 0000000000000000 00000000800c000c 00000001ffffffff 0000000000000000
[   29.387624] page dumped because: kasan: bad access detected

[   29.387920] Memory state around the buggy address:
[   29.388771]  ffff888067172080: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
[   29.390062]  ffff888067172100: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
[   29.391325] >ffff888067172180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   29.392578]                                         ^
[   29.393480]  ffff888067172200: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
[   29.394744]  ffff888067172280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[   29.396003] ==================================================================
[   29.397260] Disabling lock debugging due to kernel taint

io_sq_wq_submit_work free and read req again.

Cc: Zhengyuan Liu <liuzhengyuan@kylinos.cn>
Cc: linux-block@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: f7b76ac9d17e ("io_uring: fix counter inc/dec mismatch in async_list")
Signed-off-by: NJackie Liu <liuyun01@kylinos.cn>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit 36703247d5f52a679df9da51192b6950fe81689f upstream.

Daniel reports that when testing an http server that uses io_uring
to poll for incoming connections, sometimes it hard crashes. This is
due to an uninitialized list member for the io_uring request. Normally
this doesn't trigger and none of the test cases caught it.
Reported-by: NDaniel Kozak <kozzi11@gmail.com>
Tested-by: NDaniel Kozak <kozzi11@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit 9310a7ba6de8cce6209e3e8a3cdf733f824cdd9b upstream.

We are using PAGE_SIZE as the unit to determine if the total len in
async_list has exceeded max_pages, it's not fair for smaller io sizes.
For example, if we are doing 1k-size io streams, we will never exceed
max_pages since len >>= PAGE_SHIFT always gets zero. So use original
bytes to make it more accurate.
Signed-off-by: NZhengyuan Liu <liuzhengyuan@kylinos.cn>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit bd11b3a391e3df6fa958facbe4b3f9f4cca9bd49 upstream.

Hrvoje reports that when a large fixed buffer is registered and IO is
being done to the latter pages of said buffer, the IO submission time
is much worse:

reading to the start of the buffer: 11238 ns
reading to the end of the buffer:   1039879 ns

In fact, it's worse by two orders of magnitude. The reason for that is
how io_uring figures out how to setup the iov_iter. We point the iter
at the first bvec, and then use iov_iter_advance() to fast-forward to
the offset within that buffer we need.

However, that is abysmally slow, as it entails iterating the bvecs
that we setup as part of buffer registration. There's really no need
to use this generic helper, as we know it's a BVEC type iterator, and
we also know that each bvec is PAGE_SIZE in size, apart from possibly
the first and last. Hence we can just use a shift on the offset to
find the right index, and then adjust the iov_iter appropriately.
After this fix, the timings are:

reading to the start of the buffer: 10135 ns
reading to the end of the buffer:   1377 ns

Or about an 755x improvement for the tail page.
Reported-by: NHrvoje Zeba <zeba.hrvoje@gmail.com>
Tested-by: NHrvoje Zeba <zeba.hrvoje@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit c0e48f9dea9129aa11bec3ed13803bcc26e96e49 upstream.

There is a hang issue while using fio to do some basic test. The issue
can be easily reproduced using the below script:

        while true
        do
                fio  --ioengine=io_uring  -rw=write -bs=4k -numjobs=1 \
                     -size=1G -iodepth=64 -name=uring   --filename=/dev/zero
        done

After several minutes (or more), fio would block at
io_uring_enter->io_cqring_wait in order to waiting for previously
committed sqes to be completed and can't return to user anymore until
we send a SIGTERM to fio. After receiving SIGTERM, fio hangs at
io_ring_ctx_wait_and_kill with a backtrace like this:

        [54133.243816] Call Trace:
        [54133.243842]  __schedule+0x3a0/0x790
        [54133.243868]  schedule+0x38/0xa0
        [54133.243880]  schedule_timeout+0x218/0x3b0
        [54133.243891]  ? sched_clock+0x9/0x10
        [54133.243903]  ? wait_for_completion+0xa3/0x130
        [54133.243916]  ? _raw_spin_unlock_irq+0x2c/0x40
        [54133.243930]  ? trace_hardirqs_on+0x3f/0xe0
        [54133.243951]  wait_for_completion+0xab/0x130
        [54133.243962]  ? wake_up_q+0x70/0x70
        [54133.243984]  io_ring_ctx_wait_and_kill+0xa0/0x1d0
        [54133.243998]  io_uring_release+0x20/0x30
        [54133.244008]  __fput+0xcf/0x270
        [54133.244029]  ____fput+0xe/0x10
        [54133.244040]  task_work_run+0x7f/0xa0
        [54133.244056]  do_exit+0x305/0xc40
        [54133.244067]  ? get_signal+0x13b/0xbd0
        [54133.244088]  do_group_exit+0x50/0xd0
        [54133.244103]  get_signal+0x18d/0xbd0
        [54133.244112]  ? _raw_spin_unlock_irqrestore+0x36/0x60
        [54133.244142]  do_signal+0x34/0x720
        [54133.244171]  ? exit_to_usermode_loop+0x7e/0x130
        [54133.244190]  exit_to_usermode_loop+0xc0/0x130
        [54133.244209]  do_syscall_64+0x16b/0x1d0
        [54133.244221]  entry_SYSCALL_64_after_hwframe+0x49/0xbe

The reason is that we had added a req to ctx->pending_async at the very
end, but it didn't get a chance to be processed. How could this happen?

        fio#cpu0                                        wq#cpu1

        io_add_to_prev_work                    io_sq_wq_submit_work

          atomic_read() <<< 1

                                                  atomic_dec_return() << 1->0
                                                  list_empty();    <<< true;

          list_add_tail()
          atomic_read() << 0 or 1?

As atomic_ops.rst states, atomic_read does not guarantee that the
runtime modification by any other thread is visible yet, so we must take
care of that with a proper implicit or explicit memory barrier.

This issue was detected with the help of Jackie's <liuyun01@kylinos.cn>

Fixes: 31b515106428 ("io_uring: allow workqueue item to handle multiple buffered requests")
Signed-off-by: NZhengyuan Liu <liuzhengyuan@kylinos.cn>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit b772434be0891ed1081a08ae7cfd4666728f8e82 upstream.

task->saved_sigmask and ->restore_sigmask are only used in the ret-from-
syscall paths.  This means that set_user_sigmask() can save ->blocked in
->saved_sigmask and do set_restore_sigmask() to indicate that ->blocked
was modified.

This way the callers do not need 2 sigset_t's passed to set/restore and
restore_user_sigmask() renamed to restore_saved_sigmask_unless() turns
into the trivial helper which just calls restore_saved_sigmask().

Link: http://lkml.kernel.org/r/20190606113206.GA9464@redhat.comSigned-off-by: NOleg Nesterov <oleg@redhat.com>
Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Eric Wong <e@80x24.org>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: David Laight <David.Laight@aculab.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit f7b76ac9d17e16e44feebb6d2749fec92bfd6dd4 upstream.

We could queue a work for each req in defer and link list without
increasing async_list->cnt, so we shouldn't decrease it while exiting
from workqueue as well if we didn't process the req in async list.

Thanks to Jens Axboe <axboe@kernel.dk> for his guidance.

Fixes: 31b515106428 ("io_uring: allow workqueue item to handle multiple buffered requests")
Signed-off-by: NZhengyuan Liu <liuzhengyuan@kylinos.cn>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit dbd0f6d6c2a11eb9c31ca9cd454f95bb5713e92e upstream.

sq->cached_sq_head and cq->cached_cq_tail are both unsigned int. If
cached_sq_head overflows before cached_cq_tail, then we may miss a
barrier req. As cached_cq_tail always follows cached_sq_head, the NQ
should be enough.

Cc: stable@vger.kernel.org
Fixes: de0617e46717 ("io_uring: add support for marking commands as draining")
Signed-off-by: NZhengyuan Liu <liuzhengyuan@kylinos.cn>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit a4c0b3decb33fb4a2b5ecc6234a50680f0b21e7d upstream.

INFO: task syz-executor.5:8634 blocked for more than 143 seconds.
       Not tainted 5.2.0-rc5+ #3
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5  D25632  8634   8224 0x00004004
Call Trace:
  context_switch kernel/sched/core.c:2818 [inline]
  __schedule+0x658/0x9e0 kernel/sched/core.c:3445
  schedule+0x131/0x1d0 kernel/sched/core.c:3509
  schedule_timeout+0x9a/0x2b0 kernel/time/timer.c:1783
  do_wait_for_common+0x35e/0x5a0 kernel/sched/completion.c:83
  __wait_for_common kernel/sched/completion.c:104 [inline]
  wait_for_common kernel/sched/completion.c:115 [inline]
  wait_for_completion+0x47/0x60 kernel/sched/completion.c:136
  kthread_stop+0xb4/0x150 kernel/kthread.c:559
  io_sq_thread_stop fs/io_uring.c:2252 [inline]
  io_finish_async fs/io_uring.c:2259 [inline]
  io_ring_ctx_free fs/io_uring.c:2770 [inline]
  io_ring_ctx_wait_and_kill+0x268/0x880 fs/io_uring.c:2834
  io_uring_release+0x5d/0x70 fs/io_uring.c:2842
  __fput+0x2e4/0x740 fs/file_table.c:280
  ____fput+0x15/0x20 fs/file_table.c:313
  task_work_run+0x17e/0x1b0 kernel/task_work.c:113
  tracehook_notify_resume include/linux/tracehook.h:185 [inline]
  exit_to_usermode_loop arch/x86/entry/common.c:168 [inline]
  prepare_exit_to_usermode+0x402/0x4f0 arch/x86/entry/common.c:199
  syscall_return_slowpath+0x110/0x440 arch/x86/entry/common.c:279
  do_syscall_64+0x126/0x140 arch/x86/entry/common.c:304
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x412fb1
Code: 80 3b 7c 0f 84 c7 02 00 00 c7 85 d0 00 00 00 00 00 00 00 48 8b 05 cf
a6 24 00 49 8b 14 24 41 b9 cb 2a 44 00 48 89 ee 48 89 df <48> 85 c0 4c 0f
45 c8 45 31 c0 31 c9 e8 0e 5b 00 00 85 c0 41 89 c7
RSP: 002b:00007ffe7ee6a180 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000412fb1
RDX: 0000001b2d920000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00000000f3a3e1f8 R09: 00000000f3a3e1fc
R10: 00007ffe7ee6a260 R11: 0000000000000293 R12: 000000000075c9a0
R13: 000000000075c9a0 R14: 0000000000024c00 R15: 000000000075bf2c

=============================================

There is an wrong logic, when kthread_park running
in front of io_sq_thread.

CPU#0					CPU#1

io_sq_thread_stop:			int kthread(void *_create):

kthread_park()
					__kthread_parkme(self);	 <<< Wrong
kthread_stop()
    << wait for self->exited
    << clear_bit KTHREAD_SHOULD_PARK

					ret = threadfn(data);
					   |
					   |- io_sq_thread
					       |- kthread_should_park()	<< false
					       |- schedule() <<< nobody wake up

stuck CPU#0				stuck CPU#1

So, use a new variable sqo_thread_started to ensure that io_sq_thread
run first, then io_sq_thread_stop.

Reported-by: syzbot+94324416c485d422fe15@syzkaller.appspotmail.com
Suggested-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJackie Liu <liuyun01@kylinos.cn>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit aa1fa28fc73ea6b740ee7b62bf3b07141883dbb8 upstream.

This is done through IORING_OP_RECVMSG. This opcode uses the same
sqe->msg_flags that IORING_OP_SENDMSG added, and we pass in the
msghdr struct in the sqe->addr field as well.

We use MSG_DONTWAIT to force an inline fast path if recvmsg() doesn't
block, and punt to async execution if it would have.
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit 0fa03c624d8fc9932d0f27c39a9deca6a37e0e17 upstream.

This is done through IORING_OP_SENDMSG. There's a new sqe->msg_flags
for the flags argument, and the msghdr struct is passed in the
sqe->addr field.

We use MSG_DONTWAIT to force an inline fast path if sendmsg() doesn't
block, and punt to async execution if it would have.
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

Cherry-pick from commit b620743077e291ae7d0debd21f50413a8c266229 upstream.

If we pass pages through an iov_iter we always already have a reference
in the caller.  Thus remove the ITER_BVEC_FLAG_NO_REF and don't take
reference to pages by default for bvec backed iov_iters.

[Joseph] Resolve conflicts since we don't have:
81ba6abd2bcd "block: loop: mark bvec as ITER_BVEC_FLAG_NO_REF"
7321ecbfc7cf "block: change how we get page references in bio_iov_iter_get_pages"
Reviewed-by: NMinwoo Im <minwoo.im.dev@gmail.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit 97abc889ee296faf95ca0e978340fb7b942a3e32 upstream.

This is the minimal fix for stable, I'll send cleanups later.

Commit 854a6ed56839 ("signal: Add restore_user_sigmask()") introduced
the visible change which breaks user-space: a signal temporary unblocked
by set_user_sigmask() can be delivered even if the caller returns
success or timeout.

Change restore_user_sigmask() to accept the additional "interrupted"
argument which should be used instead of signal_pending() check, and
update the callers.

Eric said:

: For clarity.  I don't think this is required by posix, or fundamentally to
: remove the races in select.  It is what linux has always done and we have
: applications who care so I agree this fix is needed.
:
: Further in any case where the semantic change that this patch rolls back
: (aka where allowing a signal to be delivered and the select like call to
: complete) would be advantage we can do as well if not better by using
: signalfd.
:
: Michael is there any chance we can get this guarantee of the linux
: implementation of pselect and friends clearly documented.  The guarantee
: that if the system call completes successfully we are guaranteed that no
: signal that is unblocked by using sigmask will be delivered?

Link: http://lkml.kernel.org/r/20190604134117.GA29963@redhat.com
Fixes: 854a6ed56839a40f6b5d02a2962f48841482eec4 ("signal: Add restore_user_sigmask()")
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Reported-by: NEric Wong <e@80x24.org>
Tested-by: NEric Wong <e@80x24.org>
Acked-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NDeepa Dinamani <deepa.kernel@gmail.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: <stable@vger.kernel.org>	[5.0+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit 9e645e1105ca60fbbc6bddf2fd5ef7e57ed3dca8 upstream.

With SQE links, we can create chains of dependent SQEs. One example
would be queueing an SQE that's a read from one file descriptor, with
the linked SQE being a write to another with the same set of buffers.

An SQE link will not stall the pipeline, it'll just ensure that
dependent SQEs aren't issued before the previous link has completed.

Any error at submission or completion time will break the chain of SQEs.
For completions, this also includes short reads or writes, as the next
SQE could depend on the previous one being fully completed.

Any SQE in a chain that gets canceled due to any of the above errors,
will get an CQE fill with -ECANCELED as the error value.
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit 60c112b0ada09826cc4ae6a4e55df677f76f1313 upstream.

Stephen reports:

I hit the following General Protection Fault when testing io_uring via
the io_uring engine in fio. This was on a VM running 5.2-rc5 and the
latest version of fio. The issue occurs for both null_blk and fake NVMe
drives. I have not tested bare metal or real NVMe SSDs. The fio script
used is given below.

[io_uring]
time_based=1
runtime=60
filename=/dev/nvme2n1 (note /dev/nullb0 also fails)
ioengine=io_uring
bs=4k
rw=readwrite
direct=1
fixedbufs=1
sqthread_poll=1
sqthread_poll_cpu=0

general protection fault: 0000 [#1] SMP PTI
CPU: 0 PID: 872 Comm: io_uring-sq Not tainted 5.2.0-rc5-cpacket-io-uring #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
RIP: 0010:fput_many+0x7/0x90
Code: 01 48 85 ff 74 17 55 48 89 e5 53 48 8b 1f e8 a0 f9 ff ff 48 85 db 48 89 df 75 f0 5b 5d f3 c3 0f 1f 40 00 0f 1f 44 00 00 89 f6 <f0> 48 29 77 38 74 01 c3 55 48 89 e5 53 48 89 fb 65 48 \

RSP: 0018:ffffadeb817ebc50 EFLAGS: 00010246
RAX: 0000000000000004 RBX: ffff8f46ad477480 RCX: 0000000000001805
RDX: 0000000000000000 RSI: 0000000000000001 RDI: f18b51b9a39552b5
RBP: ffffadeb817ebc58 R08: ffff8f46b7a318c0 R09: 000000000000015d
R10: ffffadeb817ebce8 R11: 0000000000000020 R12: ffff8f46ad4cd000
R13: 00000000fffffff7 R14: ffffadeb817ebe30 R15: 0000000000000004
FS:  0000000000000000(0000) GS:ffff8f46b7a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055828f0bbbf0 CR3: 0000000232176004 CR4: 00000000003606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ? fput+0x13/0x20
 io_free_req+0x20/0x40
 io_put_req+0x1b/0x20
 io_submit_sqe+0x40a/0x680
 ? __switch_to_asm+0x34/0x70
 ? __switch_to_asm+0x40/0x70
 io_submit_sqes+0xb9/0x160
 ? io_submit_sqes+0xb9/0x160
 ? __switch_to_asm+0x40/0x70
 ? __switch_to_asm+0x34/0x70
 ? __schedule+0x3f2/0x6a0
 ? __switch_to_asm+0x34/0x70
 io_sq_thread+0x1af/0x470
 ? __switch_to_asm+0x34/0x70
 ? wait_woken+0x80/0x80
 ? __switch_to+0x85/0x410
 ? __switch_to_asm+0x40/0x70
 ? __switch_to_asm+0x34/0x70
 ? __schedule+0x3f2/0x6a0
 kthread+0x105/0x140
 ? io_submit_sqes+0x160/0x160
 ? kthread+0x105/0x140
 ? io_submit_sqes+0x160/0x160
 ? kthread_destroy_worker+0x50/0x50
 ret_from_fork+0x35/0x40

which occurs because using a kernel side submission thread isn't valid
without using fixed files (registered through io_uring_register()). This
causes io_uring to put the request after logging an error, but before
the file field is set in the request. If it happens to be non-zero, we
attempt to fput() garbage.

Fix this by ensuring that req->file is initialized when the request is
allocated.

Cc: stable@vger.kernel.org # 5.1+
Reported-by: NStephen Bates <sbates@raithlin.com>
Tested-by: NStephen Bates <sbates@raithlin.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit 355e8d26f719c207aa2e00e6f3cfab3acf21769b upstream.

Opening and closing an io_uring instance leaks a UNIX domain socket
inode.  This is because the ->file of the io_uring instance's internal
UNIX domain socket is set to point to the io_uring file, but then
sock_release() sees the non-NULL ->file and assumes the inode reference
is held by the file so doesn't call iput().  That's not the case here,
since the reference is still meant to be held by the socket; the actual
inode of the io_uring file is different.

Fix this leak by NULL-ing out ->file before releasing the socket.

Reported-by: syzbot+111cb28d9f583693aefa@syzkaller.appspotmail.com
Fixes: 2b188cc1bb85 ("Add io_uring IO interface")
Cc: <stable@vger.kernel.org> # v5.1+
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit 9d93a3f5a0c0d0f79aebc597d47c7cedc852aeb5 upstream.

We can encounter a short read when we're doing buffered reads and the
data is partially cached. Right now we just return the short read, but
that forces the application to read that CQE, then issue another SQE
to finish the read. That read will not be cached, and hence will result
in an async punt.

It's more efficient to do that async punt from within the kernel, as
that will the not need two round trips more to the kernel.
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit 87e5e6dab6c2a21fab2620f37786276d202e2ce0 upstream.

Currently these functions return < 0 on error, and 0 for success.
Change that so that we return < 0 on error, but number of bytes
for success.

Some callers already treat the return value that way, others need a
slight tweak.
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit a278682dad37fd2f8d2f30d8e84e376a856ab472 upstream.

If io_copy_iov() fails, it will break the loop and report success,
albeit partially completed operation.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit 004d564f908790efe815a6510a542ac1227ef2a2 upstream.

Various fixes and changes have been applied to liburing since we
copied some select bits to the kernel testing/examples part, sync
up with liburing to get those changes.

Most notable is the change that split the CQE reading into the peek
and seen event, instead of being just a single function. Also fixes
an unsigned wrap issue in io_uring_submit(), leak of 'fd' in setup
if we fail, and various other little issues.
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit 486f069253c3c738dec62daeb16f7232b2cca065 upstream.

Currently fails with:

io_uring-bench.o: In function `main':
/home/axboe/git/linux-block/tools/io_uring/io_uring-bench.c:560: undefined reference to `pthread_create'
/home/axboe/git/linux-block/tools/io_uring/io_uring-bench.c:588: undefined reference to `pthread_join'
collect2: error: ld returned 1 exit status
Makefile:11: recipe for target 'io_uring-bench' failed
make: *** [io_uring-bench] Error 1

Move -lpthread to the end.
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

In case some drivers such virtio-blk, poll function is not implementatin
yet. Before commit 529262d5 ("block: remove ->poll_fn"), q->poll_fn
is NULL and then blk_poll() won't do poll actually.
So add a check for this to avoid NULL pointer dereference when calling
q->mq_ops->poll.
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit fdb288a679cdf6a71f3c1ae6f348ba4dae742681 upstream.

The previous patch has ensured that io_cqring_events contain
smp_rmb memory barriers, Now we can use wait_event_interruptible
to keep the code simple.
Signed-off-by: NJackie Liu <liuyun01@kylinos.cn>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit dc6ce4bc2b355a47f225a0205046b3ebf29a7f72 upstream.

Whenever smp_rmb is required to use io_cqring_events,
keep smp_rmb inside the function io_cqring_events.
Signed-off-by: NJackie Liu <liuyun01@kylinos.cn>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit 2bbcd6d3b36a75a19be4917807f54ae32dd26aba upstream.

This fixes couple of races which lead to infinite wait of park completion
with the following backtraces:

  [20801.303319] Call Trace:
  [20801.303321]  ? __schedule+0x284/0x650
  [20801.303323]  schedule+0x33/0xc0
  [20801.303324]  schedule_timeout+0x1bc/0x210
  [20801.303326]  ? schedule+0x3d/0xc0
  [20801.303327]  ? schedule_timeout+0x1bc/0x210
  [20801.303329]  ? preempt_count_add+0x79/0xb0
  [20801.303330]  wait_for_completion+0xa5/0x120
  [20801.303331]  ? wake_up_q+0x70/0x70
  [20801.303333]  kthread_park+0x48/0x80
  [20801.303335]  io_finish_async+0x2c/0x70
  [20801.303336]  io_ring_ctx_wait_and_kill+0x95/0x180
  [20801.303338]  io_uring_release+0x1c/0x20
  [20801.303339]  __fput+0xad/0x210
  [20801.303341]  task_work_run+0x8f/0xb0
  [20801.303342]  exit_to_usermode_loop+0xa0/0xb0
  [20801.303343]  do_syscall_64+0xe0/0x100
  [20801.303349]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

  [20801.303380] Call Trace:
  [20801.303383]  ? __schedule+0x284/0x650
  [20801.303384]  schedule+0x33/0xc0
  [20801.303386]  io_sq_thread+0x38a/0x410
  [20801.303388]  ? __switch_to_asm+0x40/0x70
  [20801.303390]  ? wait_woken+0x80/0x80
  [20801.303392]  ? _raw_spin_lock_irqsave+0x17/0x40
  [20801.303394]  ? io_submit_sqes+0x120/0x120
  [20801.303395]  kthread+0x112/0x130
  [20801.303396]  ? kthread_create_on_node+0x60/0x60
  [20801.303398]  ret_from_fork+0x35/0x40

 o kthread_park() waits for park completion, so io_sq_thread() loop
   should check kthread_should_park() along with khread_should_stop(),
   otherwise if kthread_park() is called before prepare_to_wait()
   the following schedule() never returns:

   CPU#0                    CPU#1

   io_sq_thread_stop():     io_sq_thread():

                               while(!kthread_should_stop() && !ctx->sqo_stop) {

      ctx->sqo_stop = 1;
      kthread_park()

	                            prepare_to_wait();
                                    if (kthread_should_stop() {
				    }
                                    schedule();   <<< nobody checks park flag,
				                  <<< so schedule and never return

 o if the flag ctx->sqo_stop is observed by the io_sq_thread() loop
   it is quite possible, that kthread_should_park() check and the
   following kthread_parkme() is never called, because kthread_park()
   has not been yet called, but few moments later is is called and
   waits there for park completion, which never happens, because
   kthread has already exited:

   CPU#0                    CPU#1

   io_sq_thread_stop():     io_sq_thread():

      ctx->sqo_stop = 1;
                               while(!kthread_should_stop() && !ctx->sqo_stop) {
                                   <<< observe sqo_stop and exit the loop
			       }

			       if (kthread_should_park())
			           kthread_parkme();  <<< never called, since was
					              <<< never parked

      kthread_park()           <<< waits forever for park completion

In the current patch we quit the loop by only kthread_should_park()
check (kthread_park() is synchronous, so kthread_should_stop() is
never observed), and we abandon ->sqo_stop flag, since it is racy.
At the end of the io_sq_thread() we unconditionally call parmke(),
since we've exited the loop by the park flag.
Signed-off-by: NRoman Penyaev <rpenyaev@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit c71ffb673cd9bb2ddc575ede9055f265b2535690 upstream.

We always pass in 0 for the cqe flags argument, since the support for
"this read hit page cache" hint was dropped.
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit 44a9bd18a0f06bba19d155aeaa11e2edce898293 upstream.

The test case we have is rightfully failing with the current kernel:

io_uring_setup(1, 0x7ffe2cafebe0), flags: IORING_SETUP_SQPOLL|IORING_SETUP_SQ_AFF, resv: 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000, sq_thread_cpu: 4
expected -1, got 3

This is in a vm, and CPU3 is the last valid one, hence asking for 4
should fail the setup with -EINVAL, not succeed. The problem is that
we're using array_index_nospec() with nr_cpu_ids as the index, hence we
wrap and end up using CPU0 instead of CPU4. This makes the setup
succeed where it should be failing.

We don't need to use array_index_nospec() as we're not indexing any
array with this. Instead just compare with nr_cpu_ids directly. This
is fine as we're checking with cpu_online() afterwards.
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit e2033e33cb3821c26d4f9e70677910827d3b7885 upstream.

When punting to workers the SQE gets copied after the initial try.
There is a race condition between reading SQE data for the initial try
and copying it for punting it to the workers.

For example io_rw_done calls kiocb->ki_complete even if it was prepared
for IORING_OP_FSYNC (and would be NULL).

The easiest solution for now is to alway prepare again in the worker.

req->file is safe to prepare though as long as it is checked before use.
Signed-off-by: NStefan Bühler <source@stbuehler.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit 7889f44dd9cee15aff1c3f7daf81ca4dfed48fc7 upstream.

This issue is found by running liburing/test/io_uring_setup test.

When test run, the testcase "attempt to bind to invalid cpu" would not
pass with messages like:
   io_uring_setup(1, 0xbfc2f7c8), \
flags: IORING_SETUP_SQPOLL|IORING_SETUP_SQ_AFF, \
resv: 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000, \
sq_thread_cpu: 2
   expected -1, got 3
   FAIL

On my system, there is:
   CPU(s) possible : 0-3
   CPU(s) online   : 0-1
   CPU(s) offline  : 2-3
   CPU(s) present  : 0-1

The sq_thread_cpu 2 is offline on my system, so the bind should fail.
But cpu_possible() will pass the check. We shouldn't be able to bind
to an offline cpu. Use cpu_online() to do the check.

After the change, the testcase run as expected: EINVAL will be returned
for cpu offlined.
Reviewed-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NShenghui Wang <shhuiw@foxmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit efeb862bd5bc001636e690debf6f9fbba98e5bfd upstream.

Currently variable ret is declared in a while-loop code block that
shadows another variable ret. When an error occurs in the while-loop
the error return in ret is not being set in the outer code block and
so the error check on ret is always going to be checking on the wrong
ret variable resulting in check that is always going to be true and
a premature return occurs.

Fix this by removing the declaration of the inner while-loop variable
ret so that shadowing does not occur.

Addresses-Coverity: ("'Constant' variable guards dead code")
Fixes: 6b06314c47e1 ("io_uring: add file set registration")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

commit 5dcf877fb13f3c6a8ba0777ef766c4af32df725d upstream.

No need to set it in io_poll_add; io_poll_complete doesn't use it to set
the result in the CQE.
Signed-off-by: NStefan Bühler <source@stbuehler.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>