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SubjectRe: KASAN: vmalloc-out-of-bounds Read in bpf_trace_run7
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I can reproduce the issue with C reproducer. This is an old known issue
though and the failure is due to memory allocation failure in
tracepoint_probe_unregister().

[ 40.807849][ T8287] Call Trace:
[ 40.808201][ T8287] dump_stack+0x77/0x97
[ 40.808695][ T8287] should_fail.cold.6+0x32/0x4c
[ 40.809238][ T8287] should_failslab+0x5/0x10
[ 40.809709][ T8287] slab_pre_alloc_hook.constprop.97+0xa0/0xd0
[ 40.810365][ T8287] ? tracepoint_probe_unregister+0xc7/0x2b0
[ 40.810998][ T8287] __kmalloc+0x64/0x210
[ 40.811442][ T8287] ? trace_raw_output_percpu_destroy_chunk+0x40/0x40
[ 40.812158][ T8287] tracepoint_probe_unregister+0xc7/0x2b0
[ 40.812766][ T8287] bpf_raw_tp_link_release+0x11/0x20
[ 40.813328][ T8287] bpf_link_free+0x20/0x40
[ 40.813802][ T8287] bpf_link_release+0xc/0x10
[ 40.814242][ T8287] __fput+0xa1/0x250
[ 40.814606][ T8287] task_work_run+0x68/0xb0
[ 40.815030][ T8287] exit_to_user_mode_prepare+0x22c/0x250

Steven Rostedt has the following pending patch
https://lore.kernel.org/bpf/20201118093405.7a6d2290@gandalf.local.home/
trying to solve this exact problem.

On 1/20/21 11:14 PM, syzbot wrote:
> syzbot has bisected this issue to:
>
> commit 8b401f9ed2441ad9e219953927a842d24ed051fc
> Author: Yonghong Song <yhs@fb.com>
> Date: Thu May 23 21:47:45 2019 +0000
>
> bpf: implement bpf_send_signal() helper
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=123408e7500000
> start commit: 7d68e382 bpf: Permit size-0 datasec
> git tree: bpf-next
> final oops: https://syzkaller.appspot.com/x/report.txt?x=113408e7500000
> console output: https://syzkaller.appspot.com/x/log.txt?x=163408e7500000
> kernel config: https://syzkaller.appspot.com/x/.config?x=e0c7843b8af99dff
> dashboard link: https://syzkaller.appspot.com/bug?extid=fad5d91c7158ce568634
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1224daa4d00000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13dfabd0d00000
>
> Reported-by: syzbot+fad5d91c7158ce568634@syzkaller.appspotmail.com
> Fixes: 8b401f9ed244 ("bpf: implement bpf_send_signal() helper")
>
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection
>

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