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From:   Aleksandr Nogikh <nogikh@google.com>
Date:   Wed, 10 May 2023 11:20:03 +0200
Message-ID: <CANp29Y7ouFvWhRUxQJyhhWWDizjmeFAhfRm5nnAautDf8Z1_Cg@mail.gmail.com>
Subject: Re: [syzbot] upstream boot error: BUG: unable to handle kernel NULL
 pointer dereference in do_page_fault
To:     syzbot <syzbot+49207572d7fa5be562a0@syzkaller.appspotmail.com>
Cc:     brgl@bgdev.pl, linus.walleij@linaro.org,
        linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
        syzkaller-bugs@googlegroups.com
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FWIW this is a yet another manifestation of
https://lore.kernel.org/all/CANp29Y4Q-VWEWeHmZu0f9tLLik1Va8oDF-s8hAeVkBZbX4=
K0gg@mail.gmail.com/

#syz dup: upstream boot error: BUG: unable to handle kernel NULL
pointer dereference in load_balance

On Tue, May 9, 2023 at 11:04=E2=80=AFPM syzbot
<syzbot+49207572d7fa5be562a0@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    ba0ad6ed89fd media: nxp: imx8-isi: fix buiding on 32-bit
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=3D15c3d40c28000=
0
> kernel config:  https://syzkaller.appspot.com/x/.config?x=3Dcc86fee671999=
11d
> dashboard link: https://syzkaller.appspot.com/bug?extid=3D49207572d7fa5be=
562a0
> compiler:       arm-linux-gnueabi-gcc (Debian 10.2.1-6) 10.2.1 20210110, =
GNU ld (GNU Binutils for Debian) 2.35.2
> userspace arch: arm
>
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/c=
35b5b2731d2/non_bootable_disk-ba0ad6ed.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/590de311efa7/vmlinu=
x-ba0ad6ed.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/7007b545886c/z=
Image-ba0ad6ed.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the comm=
it:
> Reported-by: syzbot+49207572d7fa5be562a0@syzkaller.appspotmail.com
>
> Movable zone start for each node
> Early memory node ranges
>   node   0: [mem 0x0000000080000000-0x00000000ffffffff]
> Initmem setup node 0 [mem 0x0000000080000000-0x00000000ffffffff]
> percpu: Embedded 19 pages/cpu s47048 r8192 d22584 u77824
> Kernel command line: root=3D/dev/vda console=3DttyAMA0  earlyprintk=3Dser=
ial net.ifnames=3D0 sysctl.kernel.hung_task_all_cpu_backtrace=3D1 ima_polic=
y=3Dtcb nf-conntrack-ftp.ports=3D20000 nf-conntrack-tftp.ports=3D20000 nf-c=
onntrack-sip.ports=3D20000 nf-conntrack-irc.ports=3D20000 nf-conntrack-sane=
.ports=3D20000 binder.debug_mask=3D0 rcupdate.rcu_expedited=3D1 rcupdate.rc=
u_cpu_stall_cputime=3D1 no_hash_pointers page_owner=3Don sysctl.vm.nr_hugep=
ages=3D4 sysctl.vm.nr_overcommit_hugepages=3D4 secretmem.enable=3D1 sysctl.=
max_rcu_stall_to_panic=3D1 msr.allow_writes=3Doff coredump_filter=3D0xffff =
root=3D/dev/vda console=3DttyAMA0 vmalloc=3D512M smp.csd_lock_timeout=3D300=
000 watchdog_thresh=3D165 workqueue.watchdog_thresh=3D420 sysctl.net.core.n=
etdev_unregister_timeout_secs=3D420 dummy_hcd.num=3D2 panic_on_warn=3D1
> Unknown kernel command line parameters "earlyprintk=3Dserial page_owner=
=3Don", will be passed to user space.
> Dentry cache hash table entries: 262144 (order: 8, 1048576 bytes, linear)
> Inode-cache hash table entries: 131072 (order: 7, 524288 bytes, linear)
> Built 1 zonelists, mobility grouping on.  Total pages: 520868
> allocated 2097152 bytes of page_ext
> mem auto-init: stack:off, heap alloc:on, heap free:off
> software IO TLB: area num 2.
> software IO TLB: mapped [mem 0x00000000d9a47000-0x00000000dda47000] (64MB=
)
> Memory: 1952316K/2097152K available (24576K kernel code, 2364K rwdata, 84=
04K rodata, 2048K init, 868K bss, 128452K reserved, 16384K cma-reserved, 52=
4288K highmem)
> SLUB: HWalign=3D64, Order=3D0-3, MinObjects=3D0, CPUs=3D2, Nodes=3D1
> trace event string verifier disabled
> rcu: Preemptible hierarchical RCU implementation.
> rcu:    RCU restricting CPUs from NR_CPUS=3D8 to nr_cpu_ids=3D2.
> rcu:    RCU callback double-/use-after-free debug is enabled.
>         All grace periods are expedited (rcu_expedited).
>         Trampoline variant of Tasks RCU enabled.
>         Tracing variant of Tasks RCU enabled.
> rcu: RCU calculated value of scheduler-enlistment delay is 10 jiffies.
> rcu: Adjusting geometry for rcu_fanout_leaf=3D16, nr_cpu_ids=3D2
> NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16
> GIC physical location is 0x2c001000
> rcu: srcu_init: Setting srcu_struct sizes based on contention.
> sched_clock: 32 bits at 24MHz, resolution 41ns, wraps every 89478484971ns
> clocksource: arm,sp804: mask: 0xffffffff max_cycles: 0xffffffff, max_idle=
_ns: 1911260446275 ns
> arch_timer: cp15 timer(s) running at 62.50MHz (virt).
> clocksource: arch_sys_counter: mask: 0x1ffffffffffffff max_cycles: 0x1cd4=
2e208c, max_idle_ns: 881590405314 ns
> sched_clock: 57 bits at 63MHz, resolution 16ns, wraps every 4398046511096=
ns
> Switching to timer-based delay loop, resolution 16ns
> Console: colour dummy device 80x30
> Calibrating delay loop (skipped), value calculated using timer frequency.=
. 125.00 BogoMIPS (lpj=3D625000)
> pid_max: default: 32768 minimum: 301
> LSM: initializing lsm=3Dlockdown,capability,landlock,yama,safesetid,tomoy=
o,selinux,bpf,integrity
> landlock: Up and running.
> Yama: becoming mindful.
> TOMOYO Linux initialized
> SELinux:  Initializing.
> LSM support for eBPF active
> stackdepot: allocating hash table of 131072 entries via kvcalloc
> Mount-cache hash table entries: 4096 (order: 2, 16384 bytes, linear)
> Mountpoint-cache hash table entries: 4096 (order: 2, 16384 bytes, linear)
> CPU: Testing write buffer coherency: ok
> CPU0: Spectre BHB: enabling loop workaround for all CPUs
> CPU1: thread -1, cpu 1, socket 0, mpidr 80000001
> 8<--- cut here ---
> Unable to handle kernel NULL pointer dereference at virtual address 00000=
041 when read
> [00000041] *pgd=3D80000080004003, *pmd=3D00000000
> Internal error: Oops: 206 [#1] PREEMPT SMP ARM
> Modules linked in:
> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.4.0-rc1-syzkaller #0
> Hardware name: ARM-Versatile Express
> PC is at do_page_fault+0x14/0x3b8 arch/arm/mm/fault.c:276
> LR is at gpiod_set_raw_value_commit+0x4c/0x168 drivers/gpio/gpiolib.c:303=
0
> pc : [<802160d8>]    lr : [<808906c4>]    psr: 40000113
> sp : 82601e08  ip : 82601e50  fp : 82601e4c
> r10: 00000000  r9 : 827e1666  r8 : 00000001
> r7 : 8261ae40  r6 : 00000001  r5 : 8404f4a8  r4 : 00000002
> r3 : 802160c4  r2 : 00000001  r1 : 00000002  r0 : 831c0640
> Flags: nZcv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
> Control: 30c5387d  Table: 80003000  DAC: fffffffd
> Register r0 information: slab kmalloc-512 start 831c0600 pointer offset 6=
4 size 512
> Register r1 information: non-paged memory
> Register r2 information: non-paged memory
> Register r3 information: non-slab/vmalloc memory
> Register r4 information: non-paged memory
> Register r5 information: slab kmalloc-192 start 8404f480 pointer offset 4=
0 size 192
> Register r6 information: non-paged memory
> Register r7 information: non-slab/vmalloc memory
> Register r8 information: non-paged memory
> Register r9 information: non-slab/vmalloc memory
> Register r10 information: NULL pointer
> Register r11 information: non-slab/vmalloc memory
> Register r12 information: non-slab/vmalloc memory
> Process swapper/0 (pid: 0, stack limit =3D 0x82600000)
> Stack: (0x82601e08 to 0x82602000)
> 1e00:                   80201410 80298db8 817f6f00 817f6de8 04200002 8260=
4d40
> 1e20: ffff8d67 00000002 8404f4a8 00000001 831c0640 00000001 827e1666 0000=
0000
> 1e40: 82601e7c 82601e50 808906c4 802160d0 00000003 8404f4a8 00000001 0000=
00ff
> 1e60: dddd1798 00000001 827e1666 00000000 82601e8c 82601e80 80890d54 8089=
0684
> 1e80: 82601ea4 82601e90 80891ae8 80890d0c 8326c9dc 000000ff 82601ebc 8260=
1ea8
> 1ea0: 8107f920 80891aa4 8326c9dc 000000ff 82601ecc 82601ec0 8107dd50 8107=
f8d0
> 1ec0: 82601ee4 82601ed0 8107e09c 8107dd24 8326c9dc 84655294 82601f04 8260=
1ee8
> 1ee0: 8107ef38 8107e044 000001fd 8290cee4 00000002 dddd1798 82601f2c 8260=
1f08
> 1f00: 81080300 8107ef0c 00000000 8260c498 8261ae40 8260c4e0 00000000 827e=
1666
> 1f20: 82601f3c 82601f30 80208efc 8108025c 82601f84 82601f40 80293570 8020=
8ef4
> 1f40: 8260c440 00000000 81f86214 824af2f8 817f6f00 cbc96766 82601f84 0000=
00ea
> 1f60: 82625c7c 8260c440 00000000 8261a934 8260c440 82850000 82601f94 8260=
1f88
> 1f80: 80293b00 80293500 82601fa4 82601f98 817f7c74 80293aec 82601fb4 8260=
1fa8
> 1fa0: 82400bb8 817f7ba4 82601ff4 82601fb8 824012f8 82400bb4 00000000 0000=
0000
> 1fc0: 00000000 00000000 ffffffff 00000000 00000000 820ad698 82484a70 0000=
0000
> 1fe0: 00000000 000008e0 00000000 82601ff8 00000000 82400c24 00000000 0000=
0000
> Backtrace:
> [<802160c4>] (do_page_fault) from [<808906c4>] (gpiod_set_raw_value_commi=
t+0x4c/0x168 drivers/gpio/gpiolib.c:3030)
>  r10:00000000 r9:827e1666 r8:00000001 r7:831c0640 r6:00000001 r5:8404f4a8
>  r4:00000002
> [<80890678>] (gpiod_set_raw_value_commit) from [<80890d54>] (gpiod_set_va=
lue_nocheck+0x54/0x58 drivers/gpio/gpiolib.c:3204)
>  r10:00000000 r9:827e1666 r8:00000001 r7:dddd1798 r6:000000ff r5:00000001
>  r4:8404f4a8 r3:00000003
> [<80890d00>] (gpiod_set_value_nocheck) from [<80891ae8>] (gpiod_set_value=
+0x50/0xc0 drivers/gpio/gpiolib.c:3223)
> [<80891a98>] (gpiod_set_value) from [<8107f920>] (gpio_led_set+0x5c/0x60 =
drivers/leds/leds-gpio.c:54)
>  r5:000000ff r4:8326c9dc
> [<8107f8c4>] (gpio_led_set) from [<8107dd50>] (__led_set_brightness drive=
rs/leds/led-core.c:47 [inline])
> [<8107f8c4>] (gpio_led_set) from [<8107dd50>] (led_set_brightness_nopm dr=
ivers/leds/led-core.c:271 [inline])
> [<8107f8c4>] (gpio_led_set) from [<8107dd50>] (led_set_brightness_nosleep=
+0x38/0x5c drivers/leds/led-core.c:287)
>  r5:000000ff r4:8326c9dc
> [<8107dd18>] (led_set_brightness_nosleep) from [<8107e09c>] (led_set_brig=
htness+0x64/0x68 drivers/leds/led-core.c:264)
> [<8107e038>] (led_set_brightness) from [<8107ef38>] (led_trigger_event dr=
ivers/leds/led-triggers.c:390 [inline])
> [<8107e038>] (led_set_brightness) from [<8107ef38>] (led_trigger_event+0x=
38/0x50 drivers/leds/led-triggers.c:380)
>  r5:84655294 r4:8326c9dc
> [<8107ef00>] (led_trigger_event) from [<81080300>] (ledtrig_cpu+0xb0/0x10=
0 drivers/leds/trigger/ledtrig-cpu.c:86)
>  r7:dddd1798 r6:00000002 r5:8290cee4 r4:000001fd
> [<81080250>] (ledtrig_cpu) from [<80208efc>] (arch_cpu_idle_exit+0x14/0x1=
8 arch/arm/kernel/process.c:98)
>  r9:827e1666 r8:00000000 r7:8260c4e0 r6:8261ae40 r5:8260c498 r4:00000000
> [<80208ee8>] (arch_cpu_idle_exit) from [<80293570>] (do_idle+0x7c/0x2f0 k=
ernel/sched/idle.c:284)
> [<802934f4>] (do_idle) from [<80293b00>] (cpu_startup_entry+0x20/0x24 ker=
nel/sched/idle.c:379)
>  r10:82850000 r9:8260c440 r8:8261a934 r7:00000000 r6:8260c440 r5:82625c7c
>  r4:000000ea
> [<80293ae0>] (cpu_startup_entry) from [<817f7c74>] (rest_init+0xdc/0xe0 i=
nit/main.c:735)
> [<817f7b98>] (rest_init) from [<82400bb8>] (arch_post_acpi_subsys_init+0x=
0/0x20 init/main.c:834)
> [<82400ba8>] (arch_call_rest_init) from [<824012f8>] (start_kernel+0x6e0/=
0x70c init/main.c:1088)
> [<82400c18>] (start_kernel) from [<00000000>] (0x0)
> Code: e92ddff0 e24cb004 e24dd01c ee1d7f70 (e5923040)
> ---[ end trace 0000000000000000 ]---
> ----------------
> Code disassembly (best guess):
>    0:   e92ddff0        push    {r4, r5, r6, r7, r8, r9, sl, fp, ip, lr, =
pc}
>    4:   e24cb004        sub     fp, ip, #4
>    8:   e24dd01c        sub     sp, sp, #28
>    c:   ee1d7f70        mrc     15, 0, r7, cr13, cr0, {3}
> * 10:   e5923040        ldr     r3, [r2, #64]   ; 0x40 <-- trapping instr=
uction
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>
> If the bug is already fixed, let syzbot know by replying with:
> #syz fix: exact-commit-title
>
> If you want to change bug's subsystems, reply with:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
>
> If the bug is a duplicate of another bug, reply with:
> #syz dup: exact-subject-of-another-report
>
> If you want to undo deduplication, reply with:
> #syz undup
>
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