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Date:   Mon, 21 Mar 2022 13:46:29 +0100
From:   "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
To:     Geliang Tang <geliang.tang@suse.com>
Cc:     "ast@kernel.org" <ast@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "memxor@gmail.com" <memxor@gmail.com>,
        "sashal@kernel.org" <sashal@kernel.org>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>,
        Guoqing Jiang <guoqing.jiang@suse.com>,
        Kai Liu <kai.liu@suse.com>
Subject: Re: [PATCH 5.10 37/71] selftests/bpf: Add test for bpf_timer
 overwriting crash
Message-ID: <YjhzpQgUR06JGYdG@kroah.com>
References: <HE1PR0402MB3497CB13A12C4D15D20A1FCCF8139@HE1PR0402MB3497.eurprd04.prod.outlook.com>
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On Fri, Mar 18, 2022 at 02:42:49PM +0000, Geliang Tang wrote:
> Hi Greg,
> 
> I got this bpf selftests build break today on the stable branch 5.10.106:
> 
> =========================================================================
> CLNG-LLC [test_maps] test_tracepoint.o
> progs/timer_crash.c:8:19: error: field has incomplete type 'struct bpf_timer'
>         struct bpf_timer timer;
>                          ^
> progs/timer_crash.c:8:9: note: forward declaration of 'struct bpf_timer'
>         struct bpf_timer timer;
>                ^
> progs/timer_crash.c:35:6: warning: implicit declaration of function 'bpf_get_current_task_btf' is invalid in C99 [-Wimplicit-function-declaration]
>         if (bpf_get_current_task_btf()->tgid != pid)
>             ^
> progs/timer_crash.c:35:34: error: member reference type 'int' is not a pointer
>         if (bpf_get_current_task_btf()->tgid != pid)
>             ~~~~~~~~~~~~~~~~~~~~~~~~~~  ^
> progs/timer_crash.c:49:3: warning: implicit declaration of function 'bpf_timer_cancel' is invalid in C99 [-Wimplicit-function-declaration]
>                 bpf_timer_cancel(&e->timer);
>                 ^
> 2 warnings and 2 errors generated.
>   CLNG-LLC [test_maps] test_trace_ext_tracing.o
> llc: error: llc: <stdin>:1:1: error: expected top-level entity
> BPF obj compilation failed
> ^
> make: *** [Makefile:402: tools/testing/selftests/bpf/timer_crash.o] Error 1
> make: *** Waiting for unfinished jobs....
>   CLNG-LLC [test_maps] test_trace_ext.o
> =========================================================================
> 
> It is introduced by this commit, "selftests/bpf: Add test for bpf_timer
> overwriting crash". Since the commit "bpf: Introduce bpf timers." has not
> been merged into the stable branch yet.
> 
> I am writing to you to report this bug.
> 

Now reverted, thanks!

greg k-h