Re: next: arm64: boot: kernel BUG at mm/usercopy.c:102 - pc : usercopy_abort

[Eric Dumazet <edumazet@google.com>]

On Thu, Feb 9, 2023 at 9:57 AM Naresh Kamboju <naresh.kamboju@linaro.org> wrote:
>
> Following kernel crash noticed while booting arm64 devices and qemu-arm64 with
> kselftest merge configs enabled.
>
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
>
> crash log:
> ----------
> usercopy: Kernel memory exposure attempt detected from SLUB object
> 'skbuff_small_head' (offset 130, size 12)!
> ..
> [   24.673364] ------------[ cut here ]------------
> [   24.673812] kernel BUG at mm/usercopy.c:102!
> [   24.674631] Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
> [   24.675389] Modules linked in:
> [   24.676231] CPU: 3 PID: 1 Comm: systemd Not tainted
> 6.2.0-rc7-next-20230209 #1
> [   24.676779] Hardware name: linux,dummy-virt (DT)
> [   24.677256] pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
> [   24.677695] pc : usercopy_abort (mm/usercopy.c:102 (discriminator 24))
> [   24.678470] lr : usercopy_abort (mm/usercopy.c:102 (discriminator 24))
> [   24.678717] sp : ffff80000803bab0
> [   24.678949] x29: ffff80000803bac0 x28: ffff0000c0838040 x27: ffff80000803bc70
> [   24.679618] x26: 0000000000000000 x25: ffff0000c0fe4040 x24: ffff0000c4752000
> [   24.680050] x23: 0000000000000000 x22: 0000000000000020 x21: 0000000000000000
> [   24.680484] x20: ffffc94cf339ac70 x19: ffffc94cf31861b8 x18: 0000000000000000
> [   24.680929] x17: 63656a626f204255 x16: 4c53206f74206465 x15: 7463657465642074
> [   24.681372] x14: 706d657474612065 x13: 2129323320657a69 x12: 0000000000000001
> [   24.681810] x11: ffffc94cf372ba24 x10: 65685f6c6c616d73 x9 : ffffc94cf1184028
> [   24.682299] x8 : ffff80000803b7b8 x7 : ffffc94cf4207170 x6 : 0000000000000001
> [   24.682742] x5 : 0000000000000001 x4 : ffffc94cf4165000 x3 : 0000000000000000
> [   24.683216] x2 : 0000000000000000 x1 : ffff0000c0838040 x0 : 000000000000006a
> [   24.683788] Call trace:
> [   24.684019] usercopy_abort (mm/usercopy.c:102 (discriminator 24))
> [   24.684346] __check_heap_object (mm/slub.c:4739)
> [   24.684621] __check_object_size (mm/usercopy.c:196
> mm/usercopy.c:251 mm/usercopy.c:213)
> [   24.684883] netlink_sendmsg (include/linux/uio.h:177
> include/linux/uio.h:184 include/linux/skbuff.h:3977
> net/netlink/af_netlink.c:1927)
> [   24.685161] __sys_sendto (net/socket.c:722 net/socket.c:745
> net/socket.c:2142)
> [   24.685397] __arm64_sys_sendto (net/socket.c:2150)
> [   24.685644] invoke_syscall (arch/arm64/include/asm/current.h:19
> arch/arm64/kernel/syscall.c:57)
> [   24.685891] el0_svc_common.constprop.0
> (arch/arm64/include/asm/daifflags.h:28
> arch/arm64/kernel/syscall.c:150)
> [   24.686164] do_el0_svc (arch/arm64/kernel/syscall.c:194)
> [   24.686401] el0_svc (arch/arm64/include/asm/daifflags.h:28
> arch/arm64/kernel/entry-common.c:133
> arch/arm64/kernel/entry-common.c:142
> arch/arm64/kernel/entry-common.c:638)
> [   24.686602] el0t_64_sync_handler (arch/arm64/kernel/entry-common.c:656)
> [   24.686862] el0t_64_sync (arch/arm64/kernel/entry.S:591)
> [ 24.687307] Code: aa1303e3 9000ea60 91300000 97f49682 (d4210000)
> All code
> ========
>    0:* e3 03                jrcxz  0x5 <-- trapping instruction
>    2: 13 aa 60 ea 00 90    adc    -0x6fff15a0(%rdx),%ebp
>    8: 00 00                add    %al,(%rax)
>    a: 30 91 82 96 f4 97    xor    %dl,-0x680b697e(%rcx)
>   10: 00 00                add    %al,(%rax)
>   12: 21 d4                and    %edx,%esp
>
> Code starting with the faulting instruction
> ===========================================
>    0: 00 00                add    %al,(%rax)
>    2: 21 d4                and    %edx,%esp
> [   24.688236] ---[ end trace 0000000000000000 ]---
> [   24.688722] note: systemd[1] exited with irqs disabled
> [   24.689588] note: systemd[1] exited with preempt_count 1
> [   24.690331] Kernel panic - not syncing: Attempted to kill init!
> exitcode=0x0000000b
> [   24.690875] SMP: stopping secondary CPUs
> [   24.691749] Kernel Offset: 0x494ce9000000 from 0xffff800008000000
> [   24.692103] PHYS_OFFSET: 0x40000000
> [   24.692349] CPU features: 0x000000,0068c25f,3326773f
> [   24.692924] Memory Limit: none
> [   24.693422] ---[ end Kernel panic - not syncing: Attempted to kill
> init! exitcode=0x0000000b ]---
>
>
> detailed boot logs:
> https://lkft.validation.linaro.org/scheduler/job/6145112#L778
> https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20230209/testrun/14667540/suite/log-parser-test/tests/
> https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20230209/testrun/14667540/suite/log-parser-test/test/check-kernel-bug/log
>
>
> metadata:
>   git_ref: master
>   git_repo: https://gitlab.com/Linaro/lkft/mirrors/next/linux-next
>   git_sha: 20f513df926fac0594a3b65f79d856bd64251861
>   git_describe: next-20230209
>   kernel_version: 6.2.0-rc7
>   kernel-config:
> https://storage.tuxsuite.com/public/linaro/lkft/builds/2LUB6A6xC34mySgwQ3vPa6kHKJS/config
>   artifact-location:
> https://storage.tuxsuite.com/public/linaro/lkft/builds/2LUB6A6xC34mySgwQ3vPa6kHKJS/
>   toolchain: gcc-11
>   build_name: gcc-11-lkftconfig-kselftest
>
>
> --
> Linaro LKFT
> https://lkft.linaro.org

This should be fixed when this patch is accepted/merged.

https://patchwork.kernel.org/project/netdevbpf/patch/20230208142508.3278406-1-edumazet@google.com/

Thanks.