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linux/net/mptcp
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Matthieu Baerts (NGI0) 3deb12c788 mptcp: init: protect sched with rcu_read_lock 
Enabling CONFIG_PROVE_RCU_LIST with its dependence CONFIG_RCU_EXPERT
creates this splat when an MPTCP socket is created:

  =============================
  WARNING: suspicious RCU usage
  6.12.0-rc2+ #11 Not tainted
  -----------------------------
  net/mptcp/sched.c:44 RCU-list traversed in non-reader section!!

  other info that might help us debug this:

  rcu_scheduler_active = 2, debug_locks = 1
  no locks held by mptcp_connect/176.

  stack backtrace:
  CPU: 0 UID: 0 PID: 176 Comm: mptcp_connect Not tainted 6.12.0-rc2+ #11
  Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
  Call Trace:
   <TASK>
   dump_stack_lvl (lib/dump_stack.c:123)
   lockdep_rcu_suspicious (kernel/locking/lockdep.c:6822)
   mptcp_sched_find (net/mptcp/sched.c:44 (discriminator 7))
   mptcp_init_sock (net/mptcp/protocol.c:2867 (discriminator 1))
   ? sock_init_data_uid (arch/x86/include/asm/atomic.h:28)
   inet_create.part.0.constprop.0 (net/ipv4/af_inet.c:386)
   ? __sock_create (include/linux/rcupdate.h:347 (discriminator 1))
   __sock_create (net/socket.c:1576)
   __sys_socket (net/socket.c:1671)
   ? __pfx___sys_socket (net/socket.c:1712)
   ? do_user_addr_fault (arch/x86/mm/fault.c:1419 (discriminator 1))
   __x64_sys_socket (net/socket.c:1728)
   do_syscall_64 (arch/x86/entry/common.c:52 (discriminator 1))
   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)

That's because when the socket is initialised, rcu_read_lock() is not
used despite the explicit comment written above the declaration of
mptcp_sched_find() in sched.c. Adding the missing lock/unlock avoids the
warning.

Fixes: 1730b2b2c5 ("mptcp: add sched in mptcp_sock")
Cc: stable@vger.kernel.org
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/523
Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20241021-net-mptcp-sched-lock-v1-1-637759cf061c@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-10-28 15:50:54 -07:00
..
bpf.c bpf: Add update_socket_protocol hook 2023-08-16 10:22:16 -07:00
crypto_test.c mptcp: fill in missing MODULE_DESCRIPTION() 2023-12-17 20:54:22 +00:00
crypto.c move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
ctrl.c mptcp: disable active MPTCP in case of blackhole 2024-09-11 15:57:50 -07:00
diag.c mptcp: correct MPTCP_SUBFLOW_ATTR_SSN_OFFSET reserved size 2024-08-13 19:13:25 -07:00
fastopen.c mptcp: pr_debug: add missing \n at the end 2024-08-27 14:45:16 -07:00
Kconfig
Makefile net: mptcp: use policy generated by YAML spec 2023-10-24 13:00:32 -07:00
mib.c mptcp: prevent MPC handshake on port-based signal endpoints 2024-10-15 10:57:02 -07:00
mib.h mptcp: prevent MPC handshake on port-based signal endpoints 2024-10-15 10:57:02 -07:00
mptcp_diag.c mptcp: drop duplicate header inclusions 2024-03-06 20:24:10 -08:00
mptcp_pm_gen.c mptcp: add token for get-addr in yaml 2024-03-04 13:07:45 +00:00
mptcp_pm_gen.h mptcp: add token for get-addr in yaml 2024-03-04 13:07:45 +00:00
options.c mptcp: pr_debug: add missing \n at the end 2024-08-27 14:45:16 -07:00
pm_netlink.c mptcp: pm: fix UaF read in mptcp_pm_nl_rm_addr_or_subflow 2024-10-17 12:06:55 +02:00
pm_userspace.c mptcp: pm: reduce entries iterations on connect 2024-09-03 15:25:42 -07:00
pm.c mptcp: pm: reduce entries iterations on connect 2024-09-03 15:25:42 -07:00
protocol.c mptcp: init: protect sched with rcu_read_lock 2024-10-28 15:50:54 -07:00
protocol.h mptcp: prevent MPC handshake on port-based signal endpoints 2024-10-15 10:57:02 -07:00
sched.c mptcp: pr_debug: add missing \n at the end 2024-08-27 14:45:16 -07:00
sockopt.c mptcp: pr_debug: add missing \n at the end 2024-08-27 14:45:16 -07:00
subflow.c mptcp: prevent MPC handshake on port-based signal endpoints 2024-10-15 10:57:02 -07:00
syncookies.c
token_test.c mptcp: token kunit: set protocol 2024-02-26 18:42:12 -08:00
token.c