d6938c1c76
Inside decrement_ttl() upon discovering that the packet ttl has exceeded, __IP_INC_STATS and __IP6_INC_STATS macros can be called from preemptible context having the following backtrace: check_preemption_disabled: 48 callbacks suppressed BUG: using __this_cpu_add() in preemptible [00000000] code: curl/1177 caller is decrement_ttl+0x217/0x830 CPU: 5 PID: 1177 Comm: curl Not tainted 6.7.0+ #34 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0xbd/0xe0 check_preemption_disabled+0xd1/0xe0 decrement_ttl+0x217/0x830 __ip_vs_get_out_rt+0x4e0/0x1ef0 ip_vs_nat_xmit+0x205/0xcd0 ip_vs_in_hook+0x9b1/0x26a0 nf_hook_slow+0xc2/0x210 nf_hook+0x1fb/0x770 __ip_local_out+0x33b/0x640 ip_local_out+0x2a/0x490 __ip_queue_xmit+0x990/0x1d10 __tcp_transmit_skb+0x288b/0x3d10 tcp_connect+0x3466/0x5180 tcp_v4_connect+0x1535/0x1bb0 __inet_stream_connect+0x40d/0x1040 inet_stream_connect+0x57/0xa0 __sys_connect_file+0x162/0x1a0 __sys_connect+0x137/0x160 __x64_sys_connect+0x72/0xb0 do_syscall_64+0x6f/0x140 entry_SYSCALL_64_after_hwframe+0x6e/0x76 RIP: 0033:0x7fe6dbbc34e0 Use the corresponding preemption-aware variants: IP_INC_STATS and IP6_INC_STATS. Found by Linux Verification Center (linuxtesting.org). Fixes: 8d8e20e2d7bb ("ipvs: Decrement ttl") Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru> Acked-by: Julian Anastasov <ja@ssi.bg> Acked-by: Simon Horman <horms@kernel.org> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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 Restructured Text 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.