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Eric Dumazet f130a0cc1b inet: fix lwtunnel_valid_encap_type() lock imbalance
After blamed commit rtm_to_fib_config() now calls
lwtunnel_valid_encap_type{_attr}() without RTNL held,
triggering an unlock balance in __rtnl_unlock,
as reported by syzbot [1]

IPv6 and rtm_to_nh_config() are not yet converted.

Add a temporary @rtnl_is_held parameter to lwtunnel_valid_encap_type()
and lwtunnel_valid_encap_type_attr().

While we are at it replace the two rcu_dereference()
in lwtunnel_valid_encap_type() with more appropriate
rcu_access_pointer().

[1]
syz-executor245/5836 is trying to release lock (rtnl_mutex) at:
 [<ffffffff89d0e38c>] __rtnl_unlock+0x6c/0xf0 net/core/rtnetlink.c:142
but there are no more locks to release!

other info that might help us debug this:
no locks held by syz-executor245/5836.

stack backtrace:
CPU: 0 UID: 0 PID: 5836 Comm: syz-executor245 Not tainted 6.14.0-rc4-syzkaller-00873-g3424291dd242 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
  __dump_stack lib/dump_stack.c:94 [inline]
  dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
  print_unlock_imbalance_bug+0x25b/0x2d0 kernel/locking/lockdep.c:5289
  __lock_release kernel/locking/lockdep.c:5518 [inline]
  lock_release+0x47e/0xa30 kernel/locking/lockdep.c:5872
  __mutex_unlock_slowpath+0xec/0x800 kernel/locking/mutex.c:891
  __rtnl_unlock+0x6c/0xf0 net/core/rtnetlink.c:142
  lwtunnel_valid_encap_type+0x38a/0x5f0 net/core/lwtunnel.c:169
  lwtunnel_valid_encap_type_attr+0x113/0x270 net/core/lwtunnel.c:209
  rtm_to_fib_config+0x949/0x14e0 net/ipv4/fib_frontend.c:808
  inet_rtm_newroute+0xf6/0x2a0 net/ipv4/fib_frontend.c:917
  rtnetlink_rcv_msg+0x791/0xcf0 net/core/rtnetlink.c:6919
  netlink_rcv_skb+0x206/0x480 net/netlink/af_netlink.c:2534
  netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
  netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339
  netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883
  sock_sendmsg_nosec net/socket.c:709 [inline]

Fixes: 1dd2af7963 ("ipv4: fib: Convert RTM_NEWROUTE and RTM_DELROUTE to per-netns RTNL.")
Reported-by: syzbot+3f18ef0f7df107a3f6a0@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/67c6f87a.050a0220.38b91b.0147.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250304125918.2763514-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-05 19:16:56 -08:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-02-27 10:20:58 -08:00
block block-6.14-20250221 2025-02-21 09:36:28 -08:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
Documentation dt-bindings: net: Convert fsl,gianfar to YAML 2025-03-04 17:02:16 -08:00
drivers net: phy: remove remaining PHY package related definitions from phy.h 2025-03-05 19:13:53 -08:00
fs Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-02-27 10:20:58 -08:00
include inet: fix lwtunnel_valid_encap_type() lock imbalance 2025-03-05 19:16:56 -08:00
init Kbuild updates for v6.14 2025-01-31 12:07:07 -08:00
io_uring Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-02-27 10:20:58 -08:00
ipc treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
kernel ptp: Add PHC file mode checks. Allow RO adjtime() without FMODE_WRITE. 2025-03-05 12:43:54 +00:00
lib net: move aRFS rmap management and CPU affinity to core 2025-02-26 19:51:37 -08:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm vfs-6.14-rc5.fixes 2025-02-25 09:13:13 -08:00
net inet: fix lwtunnel_valid_encap_type() lock imbalance 2025-03-05 19:16:56 -08:00
rust Driver core api addition for 6.14-rc3 2025-02-16 12:54:42 -08:00
samples Driver core api addition for 6.14-rc3 2025-02-16 12:54:42 -08:00
scripts coccinelle: Add missing (GE)NL_SET_ERR_MSG_* to strings ending with newline test 2025-02-27 18:11:37 -08:00
security Landlock fix for v6.14-rc5 2025-02-26 11:55:44 -08:00
sound ASoC: Fixes for v6.14 2025-02-26 15:00:25 +01:00
tools testptp: Add option to open PHC in readonly mode 2025-03-05 12:43:54 +00:00
usr kbuild: Drop support for include/asm-<arch> in headers_check.pl 2024-12-21 11:43:17 +09:00
virt KVM: remove kvm_arch_post_init_vm 2025-02-04 11:27:45 -05:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: give Clippy the minimum supported Rust version 2025-01-10 00:17:25 +01:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: use host dylib naming convention to support macOS 2025-01-10 01:01:24 +01:00
.mailmap mailmap: update Nick's entry 2025-02-17 22:40:03 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Pavel to kernel.org address 2025-02-07 09:12:33 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS arch: x86: add IPC mailbox accessor function and add SoC register access 2025-03-05 19:02:47 -08:00
Makefile Linux 6.14-rc4 2025-02-23 12:32:57 -08:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    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.