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Antonio Quartulli a6a5e87b3e ovpn: avoid sleep in atomic context in TCP RX error path
Upon error along the TCP data_ready event path, we have
the following chain of calls:

strp_data_ready()
  ovpn_tcp_rcv()
    ovpn_peer_del()
      ovpn_socket_release()

Since strp_data_ready() may be invoked from softirq context, and
ovpn_socket_release() may sleep, the above sequence may cause a
sleep in atomic context like the following:

    BUG: sleeping function called from invalid context at ./ovpn-backports-ovpn-net-next-main-6.15.0-rc5-20250522/drivers/net/ovpn/socket.c:71
    in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 25, name: ksoftirqd/3
    5 locks held by ksoftirqd/3/25:
     #0: ffffffe000cd0580 (rcu_read_lock){....}-{1:2}, at: netif_receive_skb+0xb8/0x5b0
     OpenVPN/ovpn-backports#1: ffffffe000cd0580 (rcu_read_lock){....}-{1:2}, at: netif_receive_skb+0xb8/0x5b0
     OpenVPN/ovpn-backports#2: ffffffe000cd0580 (rcu_read_lock){....}-{1:2}, at: ip_local_deliver_finish+0x66/0x1e0
     OpenVPN/ovpn-backports#3: ffffffe003ce9818 (slock-AF_INET/1){+.-.}-{2:2}, at: tcp_v4_rcv+0x156e/0x17a0
     OpenVPN/ovpn-backports#4: ffffffe000cd0580 (rcu_read_lock){....}-{1:2}, at: ovpn_tcp_data_ready+0x0/0x1b0 [ovpn]
    CPU: 3 PID: 25 Comm: ksoftirqd/3 Not tainted 5.10.104+ #0
    Call Trace:
    walk_stackframe+0x0/0x1d0
    show_stack+0x2e/0x44
    dump_stack+0xc2/0x102
    ___might_sleep+0x29c/0x2b0
    __might_sleep+0x62/0xa0
    ovpn_socket_release+0x24/0x2d0 [ovpn]
    unlock_ovpn+0x6e/0x190 [ovpn]
    ovpn_peer_del+0x13c/0x390 [ovpn]
    ovpn_tcp_rcv+0x280/0x560 [ovpn]
    __strp_recv+0x262/0x940
    strp_recv+0x66/0x80
    tcp_read_sock+0x122/0x410
    strp_data_ready+0x156/0x1f0
    ovpn_tcp_data_ready+0x92/0x1b0 [ovpn]
    tcp_data_ready+0x6c/0x150
    tcp_rcv_established+0xb36/0xc50
    tcp_v4_do_rcv+0x25e/0x380
    tcp_v4_rcv+0x166a/0x17a0
    ip_protocol_deliver_rcu+0x8c/0x250
    ip_local_deliver_finish+0xf8/0x1e0
    ip_local_deliver+0xc2/0x2d0
    ip_rcv+0x1f2/0x330
    __netif_receive_skb+0xfc/0x290
    netif_receive_skb+0x104/0x5b0
    br_pass_frame_up+0x190/0x3f0
    br_handle_frame_finish+0x3e2/0x7a0
    br_handle_frame+0x750/0xab0
    __netif_receive_skb_core.constprop.0+0x4c0/0x17f0
    __netif_receive_skb+0xc6/0x290
    netif_receive_skb+0x104/0x5b0
    xgmac_dma_rx+0x962/0xb40
    __napi_poll.constprop.0+0x5a/0x350
    net_rx_action+0x1fe/0x4b0
    __do_softirq+0x1f8/0x85c
    run_ksoftirqd+0x80/0xd0
    smpboot_thread_fn+0x1f0/0x3e0
    kthread+0x1e6/0x210
    ret_from_kernel_thread+0x8/0xc

Fix this issue by postponing the ovpn_peer_del() call to
a scheduled worker, as we already do in ovpn_tcp_send_sock()
for the very same reason.

Fixes: 11851cbd60 ("ovpn: implement TCP transport")
Reported-by: Qingfang Deng <dqfext@gmail.com>
Closes: https://github.com/OpenVPN/ovpn-net-next/issues/13
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
2025-06-03 13:08:15 +02:00
arch bpf-next-6.16 2025-05-28 15:52:42 -07:00
block cgroup: Changes for v6.16 2025-05-27 20:59:53 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto Networking changes for 6.16. 2025-05-28 15:24:36 -07:00
Documentation bpf-next-6.16 2025-05-28 15:52:42 -07:00
drivers ovpn: avoid sleep in atomic context in TCP RX error path 2025-06-03 13:08:15 +02:00
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include bpf: Fix L4 csum update on IPv6 in CHECKSUM_COMPLETE 2025-05-30 19:53:51 -07:00
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net net: fix udp gso skb_segment after pull from frag_list 2025-06-02 12:41:33 +01:00
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samples Networking changes for 6.16. 2025-05-28 15:24:36 -07:00
scripts bpf-next-6.16 2025-05-28 15:52:42 -07:00
security Networking changes for 6.16. 2025-05-28 15:24:36 -07:00
sound sound updates for 6.16-rc1 2025-05-27 15:05:18 -07:00
tools bpf: Fix L4 csum update on IPv6 in CHECKSUM_COMPLETE 2025-05-30 19:53:51 -07:00
usr usr/include: openrisc: don't HDRTEST bpf_perf_event.h 2025-05-12 15:03:17 +09:00
virt ARM: 2025-04-08 13:47:55 -07:00
.clang-format Linux 6.15-rc5 2025-05-06 16:39:25 +10:00
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COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: update SLAB ALLOCATOR maintainers 2025-04-17 20:10:06 -07:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
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Makefile A moderately busy cycle for documentation this time around: 2025-05-27 11:22:19 -07:00
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Linux kernel
============

There are several guides for kernel developers and users. These guides can
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Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
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    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.