On Wed, Sep 20, 2023 at 03:20:58PM +0100, Mark Rutland wrote:
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@linaro.org
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.
This appears to be the same issue [1] that was sent to linux-trace-kernel. There's a proposal [2] there to get a generic set_bit_aligned() function to ensure alignment for both little and big endian devices.
Thanks, -Beau
1. https://lore.kernel.org/linux-trace-kernel/20230914131102.179100-1-cleger@ri... 2. https://lore.kernel.org/linux-trace-kernel/20230915115449.3d7103b841cd593d1a...