Re: BUG: KASAN: null-ptr-deref in _raw_spin_lock_irq next-20240410

From: Naresh Kamboju
Date: Wed Apr 10 2024 - 13:17:12 EST


On Wed, 10 Apr 2024 at 20:53, Will Deacon <will@xxxxxxxxxx> wrote:
>
> On Wed, Apr 10, 2024 at 03:57:10PM +0530, Naresh Kamboju wrote:
> > Following kernel crash noticed on Linux next-20240410 tag while running
> > kunit testing on qemu-arm64 and qemu-x86_64.
> >
> > Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>
> >
> > Crash log on qemu-arm64:
> > ----------------
> > <3>[ 30.465716] BUG: KASAN: null-ptr-deref in _raw_spin_lock_irq (include/linux/instrumented.h:96 include/linux/atomic/atomic-instrumented.h:1301 include/asm-generic/qspinlock.h:111 include/linux/spinlock.h:187 include/linux/spinlock_api_smp.h:120 kernel/locking/spinlock.c:170)

> It's a shame that you have trimmed the register dump here.

My apologies for that, the detailed crash log is attached and
the links provided in the tail of this email.

>
> > <4>[ 30.511022] Call trace:
> > <4>[ 30.511437] _raw_spin_lock_irq (arch/arm64/include/asm/atomic_lse.h:271 arch/arm64/include/asm/cmpxchg.h:120 arch/arm64/include/asm/cmpxchg.h:169 include/linux/atomic/atomic-arch-fallback.h:2055 include/linux/atomic/atomic-arch-fallback.h:2173 include/linux/atomic/atomic-instrumented.h:1302 include/asm-generic/qspinlock.h:111 include/linux/spinlock.h:187 include/linux/spinlock_api_smp.h:120 kernel/locking/spinlock.c:170)
> > <4>[ 30.512013] wait_for_completion_timeout (kernel/sched/completion.c:84 kernel/sched/completion.c:116 kernel/sched/completion.c:127 kernel/sched/completion.c:167)
> > <4>[ 30.512627] kunit_try_catch_run (lib/kunit/try-catch.c:86)
> > <4>[ 30.513188] kunit_run_case_catch_errors (lib/kunit/test.c:544)
> > <4>[ 30.513801] kunit_run_tests (lib/kunit/test.c:635)
>
> Ok, so 'task_struct->vfork_done' is NULL. Looks like this code was added
> recently, so adding Mickaël to cc.
>
> Will

Thank you.

- Naresh
Subject: BUG: KASAN: null-ptr-deref in _raw_spin_lock_irq next-20240410

Following kernel crash noticed on Linux next-20240410 tag while running
kunit testing on qemu-arm64 and qemu-x86_64.

Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>

Crash log on qemu-arm64:
----------------
<3>[ 30.465716] BUG: KASAN: null-ptr-deref in _raw_spin_lock_irq (include/linux/instrumented.h:96 include/linux/atomic/atomic-instrumented.h:1301 include/asm-generic/qspinlock.h:111 include/linux/spinlock.h:187 include/linux/spinlock_api_smp.h:120 kernel/locking/spinlock.c:170)
<3>[ 30.467097] Write of size 4 at addr 0000000000000008 by task swapper/0/1
<3>[ 30.468059]
<3>[ 30.468393] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G B N 6.9.0-rc3-next-20240410 #1
<3>[ 30.469209] Hardware name: linux,dummy-virt (DT)
<3>[ 30.469645] Call trace:
<3>[ 30.469919] dump_backtrace (arch/arm64/kernel/stacktrace.c:319)
<3>[ 30.471622] show_stack (arch/arm64/kernel/stacktrace.c:326)
<3>[ 30.472124] dump_stack_lvl (lib/dump_stack.c:117)
<3>[ 30.472947] print_report (mm/kasan/report.c:493)
<3>[ 30.473755] kasan_report (mm/kasan/report.c:603)
<3>[ 30.474524] kasan_check_range (mm/kasan/generic.c:175 mm/kasan/generic.c:189)
<3>[ 30.475094] __kasan_check_write (mm/kasan/shadow.c:38)
<3>[ 30.475683] _raw_spin_lock_irq (include/linux/instrumented.h:96 include/linux/atomic/atomic-instrumented.h:1301 include/asm-generic/qspinlock.h:111 include/linux/spinlock.h:187 include/linux/spinlock_api_smp.h:120 kernel/locking/spinlock.c:170)
<3>[ 30.476257] wait_for_completion_timeout (kernel/sched/completion.c:84 kernel/sched/completion.c:116 kernel/sched/completion.c:127 kernel/sched/completion.c:167)
<3>[ 30.476909] kunit_try_catch_run (lib/kunit/try-catch.c:86)
<3>[ 30.477628] kunit_run_case_catch_errors (lib/kunit/test.c:544)
<3>[ 30.478311] kunit_run_tests (lib/kunit/test.c:635)
<3>[ 30.478865] __kunit_test_suites_init (lib/kunit/test.c:729 (discriminator 1))
<3>[ 30.479482] kunit_run_all_tests (lib/kunit/executor.c:276 lib/kunit/executor.c:392)
<3>[ 30.480079] kernel_init_freeable (init/main.c:1578)
<3>[ 30.480747] kernel_init (init/main.c:1465)
<3>[ 30.481474] ret_from_fork (arch/arm64/kernel/entry.S:861)
<3>[ 30.482080] ==================================================================
<1>[ 30.484503] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008
<1>[ 30.485369] Mem abort info:
<1>[ 30.485923] ESR = 0x000000009600006b
<1>[ 30.486943] EC = 0x25: DABT (current EL), IL = 32 bits
<1>[ 30.487540] SET = 0, FnV = 0
<1>[ 30.488007] EA = 0, S1PTW = 0
<1>[ 30.488509] FSC = 0x2b: level -1 translation fault
<1>[ 30.489150] Data abort info:
<1>[ 30.489610] ISV = 0, ISS = 0x0000006b, ISS2 = 0x00000000
<1>[ 30.490360] CM = 0, WnR = 1, TnD = 0, TagAccess = 0
<1>[ 30.491057] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
<1>[ 30.491822] [0000000000000008] user address but active_mm is swapper
<0>[ 30.493008] Internal error: Oops: 000000009600006b [#1] PREEMPT SMP
<4>[ 30.494105] Modules linked in:
<4>[ 30.496244] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G B N 6.9.0-rc3-next-20240410 #1
<4>[ 30.497171] Hardware name: linux,dummy-virt (DT)
<4>[ 30.497905] pstate: 224000c9 (nzCv daIF +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
<4>[ 30.498895] pc : _raw_spin_lock_irq (arch/arm64/include/asm/atomic_lse.h:271 arch/arm64/include/asm/cmpxchg.h:120 arch/arm64/include/asm/cmpxchg.h:169 include/linux/atomic/atomic-arch-fallback.h:2055 include/linux/atomic/atomic-arch-fallback.h:2173 include/linux/atomic/atomic-instrumented.h:1302 include/asm-generic/qspinlock.h:111 include/linux/spinlock.h:187 include/linux/spinlock_api_smp.h:120 kernel/locking/spinlock.c:170)
<4>[ 30.499542] lr : _raw_spin_lock_irq (include/linux/atomic/atomic-arch-fallback.h:2172 (discriminator 1) include/linux/atomic/atomic-instrumented.h:1302 (discriminator 1) include/asm-generic/qspinlock.h:111 (discriminator 1) include/linux/spinlock.h:187 (discriminator 1) include/linux/spinlock_api_smp.h:120 (discriminator 1) kernel/locking/spinlock.c:170 (discriminator 1))

<trim>

<4>[ 30.511022] Call trace:
<4>[ 30.511437] _raw_spin_lock_irq (arch/arm64/include/asm/atomic_lse.h:271 arch/arm64/include/asm/cmpxchg.h:120 arch/arm64/include/asm/cmpxchg.h:169 include/linux/atomic/atomic-arch-fallback.h:2055 include/linux/atomic/atomic-arch-fallback.h:2173 include/linux/atomic/atomic-instrumented.h:1302 include/asm-generic/qspinlock.h:111 include/linux/spinlock.h:187 include/linux/spinlock_api_smp.h:120 kernel/locking/spinlock.c:170)
<4>[ 30.512013] wait_for_completion_timeout (kernel/sched/completion.c:84 kernel/sched/completion.c:116 kernel/sched/completion.c:127 kernel/sched/completion.c:167)
<4>[ 30.512627] kunit_try_catch_run (lib/kunit/try-catch.c:86)
<4>[ 30.513188] kunit_run_case_catch_errors (lib/kunit/test.c:544)
<4>[ 30.513801] kunit_run_tests (lib/kunit/test.c:635)
<4>[ 30.514674] __kunit_test_suites_init (lib/kunit/test.c:729 (discriminator 1))
<4>[ 30.515259] kunit_run_all_tests (lib/kunit/executor.c:276 lib/kunit/executor.c:392)
<4>[ 30.515831] kernel_init_freeable (init/main.c:1578)
<4>[ 30.516384] kernel_init (init/main.c:1465)
<4>[ 30.516900] ret_from_fork (arch/arm64/kernel/entry.S:861)
<0>[ 30.518151] Code: 93407c02 d503201f 2a0003e1 52800022 (88e17e62)
All code
========
0: 93407c02 sxtw x2, w0
4: d503201f nop
8: 2a0003e1 mov w1, w0
c: 52800022 mov w2, #0x1 // #1
10:* 88e17e62 casa w1, w2, [x19] <-- trapping instruction

Code starting with the faulting instruction
===========================================
0: 88e17e62 casa w1, w2, [x19]
<4>[ 30.519501] ---[ end trace 0000000000000000 ]---
<6>[ 30.520317] note: swapper/0[1] exited with irqs disabled
<6>[ 30.521355] note: swapper/0[1] exited with preempt_count 1
<0>[ 30.523129] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
<2>[ 30.524397] SMP: stopping secondary CPUs
<0>[ 30.525553] Kernel Offset: 0x25148d400000 from 0xffff800080000000
<0>[ 30.528341] PHYS_OFFSET: 0x40000000
<0>[ 30.529003] CPU features: 0x0,00000006,8f17bd7c,6766773f
<0>[ 30.530313] Memory Limit: none
<0>[ 30.531319] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b ]---

Steps to reproduce:
---
https://tuxapi.tuxsuite.com/v1/groups/linaro/projects/lkft/tests/2etdCz631GU6PILJzs8reteba8i/reproducer

Links:
- https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20240410/testrun/23381881/suite/log-parser-test/tests/
- https://tuxapi.tuxsuite.com/v1/groups/linaro/projects/lkft/tests/2etdCz631GU6PILJzs8reteba8i
- https://tuxapi.tuxsuite.com/v1/groups/linaro/projects/lkft/tests/2etdDjlx3eRFhhK9cy2UsEHAXTr

--
Linaro LKFT
https://lkft.linaro.org