Re: selftests: user_events: ftrace_test: Internal error: Oops: 0000000096000021

From: Mark Rutland
Date: Wed Sep 20 2023 - 10:21:11 EST

Hi Naresh,

As a general thing, for arm64 issues could you please Cc the linux-arm-kernel
mailing list?

On Wed, Sep 20, 2023 at 02:40:24PM +0200, Naresh Kamboju wrote:
> Following selftests: user_events: ftrace_test running on arm64 Juno-r2
> Linux next-20230919.
> Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>
>
> kselftest: Running tests in user_events
> TAP version 13
> 1..4
> # timeout set to 90
> # selftests: user_events: ftrace_test
> [ 1138.755735] Unable to handle kernel paging request at virtual address ffff00082fc89ed4
> [ 1138.763768] Mem abort info:
> [ 1138.766692] ESR = 0x0000000096000021
> [ 1138.770495] EC = 0x25: DABT (current EL), IL = 32 bits
> [ 1138.775879] SET = 0, FnV = 0
> [ 1138.779018] EA = 0, S1PTW = 0
> [ 1138.782264] FSC = 0x21: alignment fault

So this is an alignment fault, to a 4-byte aligned address...

> [ 1138.786399] Data abort info:
> [ 1138.789356] ISV = 0, ISS = 0x00000021, ISS2 = 0x00000000
> [ 1138.794969] CM = 0, WnR = 0, TnD = 0, TagAccess = 0
> [ 1138.800095] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
> [ 1138.805436] swapper pgtable: 4k pages, 48-bit VAs, pgdp=000000008265b000
> [ 1138.812175] [ffff00082fc89ed4] pgd=18000009ffdf8003,
> p4d=18000009ffdf8003, pud=18000009ffa0e003, pmd=18000009ff88f003,
> pte=00680008afc89707
> [ 1138.824824] Internal error: Oops: 0000000096000021 [#1] PREEMPT SMP
> # TAP[ 1138.831117] Modules linked in: tda998x hdlcd onboard_usb_hub
> crct10dif_ce cec drm_dma_helper drm_kms_helper drm fuse backlight
> dm_mod ip_tables x_tables
> [ 1138.845227] CPU: 1 PID: 4752 Comm: ftrace_test Not tainted
> 6.6.0-rc2-next-20230919 #1
> v[e r1s1i3o8n. 81533080] Hardware name: ARM Juno development board (r2) (DT)
>
> # 1..6
> # # Starting 6 tests from 1 test cases.
> # # RUN user.register_events ...
> [ 1138.868317] pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> [ 1138.875291] pc : user_event_enabler_write
> (arch/arm64/include/asm/atomic_ll_sc.h:210 (discriminator 2)
> arch/arm64/include/asm/atomic.h:64 (discriminator 2)
> include/linux/atomic/atomic-arch-fallback.h:3656 (discriminator 2)
> include/linux/atomic/atomic-long.h:964 (discriminator 2)

... as part of some atomic_long_*() operation, where atomic_long_t should be
8-byte aligned, so we've got a dodgy address.

> include/asm-generic/bitops/atomic.h:25 (discriminator 2)
> include/asm-generic/bitops/instrumented-atomic.h:42 (discriminator 2)
> kernel/trace/trace_events_user.c:520 (discriminator 2))
> [ 1138.880362] lr : user_event_enabler_write
> (kernel/trace/trace_events_user.c:503 (discriminator 1))
> [ 1138.885337] sp : ffff80008a593b70
> [ 1138.888656] x29: ffff80008a593b70 x28: ffff000800908040 x27: ffff00082767ac40
> [ 1138.895817] x26: 0000000000000000 x25: ffff000827732600 x24: 0000ffffc2a46ca0
> [ 1138.902972] x23: 0000000000000000 x22: ffff000822773a00 x21: 0000000000000ed4
> [ 1138.910128] x20: ffff80008a593c40 x19: ffff00082767ac40 x18: 0000000000000000
> [ 1138.917283] x17: ffff8000816f1aa0 x16: ffff80008002ce90 x15: ffff800081cea0b8
> [ 1138.924439] x14: ffffffffffffffff x13: 0000ffffadc52000 x12: 1fffe001048d5b21
> [ 1138.931597] x11: ffff0008246ad900 x10: ffff0008246ad908 x9 : ffff80008003bc40
> [ 1138.938752] x8 : ffff80008a5937d8 x7 : 0000000000000000 x6 : 0000000000000001
> [ 1138.945905] x5 : 0000000000000001 x4 : fffffc0020bf2240 x3 : 000000000000001f
> [ 1138.953058] x2 : 0000000000000000 x1 : 0000000080000000 x0 : ffff00082fc89ed4
> [ 1138.960212] Call trace:
> [ 1138.962656] user_event_enabler_write
> (arch/arm64/include/asm/atomic_ll_sc.h:210 (discriminator 2)
> arch/arm64/include/asm/atomic.h:64 (discriminator 2)
> include/linux/atomic/atomic-arch-fallback.h:3656 (discriminator 2)
> include/linux/atomic/atomic-long.h:964 (discriminator 2)
> include/asm-generic/bitops/atomic.h:25 (discriminator 2)
> include/asm-generic/bitops/instrumented-atomic.h:42 (discriminator 2)
> kernel/trace/trace_events_user.c:520 (discriminator 2))
> [ 1138.967372] user_events_ioctl (kernel/trace/trace_events_user.c:858
> kernel/trace/trace_events_user.c:2314
> kernel/trace/trace_events_user.c:2475)
> [ 1138.971477] __arm64_sys_ioctl (fs/ioctl.c:52 fs/ioctl.c:871
> fs/ioctl.c:857 fs/ioctl.c:857)
> [ 1138.975497] invoke_syscall (arch/arm64/include/asm/current.h:19
> arch/arm64/kernel/syscall.c:56)
> [ 1138.979255] el0_svc_common.constprop.0
> (include/linux/thread_info.h:127 (discriminator 2)
> arch/arm64/kernel/syscall.c:144 (discriminator 2))
> [ 1138.984056] do_el0_svc (arch/arm64/kernel/syscall.c:156)
> [ 1138.987377] el0_svc (arch/arm64/include/asm/daifflags.h:28
> arch/arm64/kernel/entry-common.c:133
> arch/arm64/kernel/entry-common.c:144
> arch/arm64/kernel/entry-common.c:679)
> [ 1138.990439] el0t_64_sync_handler (arch/arm64/kernel/entry-common.c:697)
> [ 1138.994805] el0t_64_sync (arch/arm64/kernel/entry.S:591)
> [ 1138.998474] Code: 14000009 f821301f 17ffffed f9800011 (c85f7c02)
> All code
> ========
> 0:* 09 00 or %eax,(%rax) <-- trapping instruction
> 2: 00 14 1f add %dl,(%rdi,%rbx,1)
> 5: 30 21 xor %ah,(%rcx)
> 7: f8 clc
> 8: ed in (%dx),%eax
> 9: ff (bad)
> a: ff 17 callq *(%rdi)
> c: 11 00 adc %eax,(%rax)
> e: 80 f9 02 cmp $0x2,%cl
> 11: 7c 5f jl 0x72
> 13: c8 .byte 0xc8
>
> Code starting with the faulting instruction
> ===========================================
> 0: 02 7c 5f c8 add -0x38(%rdi,%rbx,2),%bh

As a general thing, can you *please* fix the code dump to decode as arm64 as
arm64 rather than as x86?

Every arm64 report I've seen has this bogus decoding, and it's completely
useless.

Thanks,
Mark.

> [ 1139.004575] ---[ end trace 0000000000000000 ]---
> # # register_events: Test terminated by timeout
> # # FAIL user.register_events
> # not ok 1 user.register_events
> # # RUN user.write_events ...
> # # write_events: Test terminated by timeout
> # # FAIL user.write_events
> # not ok 2 user.write_events
> # # RUN user.write_empty_events ...
>
>
> Log:
> - https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20230919/testrun/20073395/suite/log-parser-test/test/check-kernel-oops/log
> - https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20230919/testrun/20073395/suite/log-parser-test/test/check-kernel-oops/details/
> - https://storage.tuxsuite.com/public/linaro/lkft/builds/2VbYWmjbGM16bFDtcoFx62Kdds2/
>
>
> --
> Linaro LKFT
> https://lkft.linaro.org