Messages in this thread | | | Date | Fri, 21 Oct 2022 10:37:35 +0100 | From | Mark Rutland <> | Subject | Re: [syzbot] BUG: unable to handle kernel paging request in percpu_counter_add_batch |
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Hi,
On Thu, Oct 20, 2022 at 07:24:40PM -0700, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: aae703b02f92 Merge tag 'for-6.1-rc1-tag' of git://git.kern.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=1686e478880000 > kernel config: https://syzkaller.appspot.com/x/.config?x=883de36878e6d869 > dashboard link: https://syzkaller.appspot.com/bug?extid=96e659d35b9d6b541152 > compiler: aarch64-linux-gnu-gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > userspace arch: arm > > Unfortunately, I don't have any reproducer for this issue yet.
I'm hitting what I believe is the same issue on my local arm64 Syzkaller instance, which came up with a reproducer (which I can confirm with syz-repro)
Full Syzkaller report below. I'm testing v6.1-rc1 with a couple of fixes atop, building with the kernel.org crosstool GCC 12.1.0 binaries.
Thanks, Mark.
-------- Syzkaller hit 'BUG: unable to handle kernel paging request in percpu_counter_add_batch' bug.
Unable to handle kernel paging request at virtual address ffff70000b396400 KASAN: maybe wild-memory-access in range [0xffff800059cb2000-0xffff800059cb2007] Mem abort info: ESR = 0x0000000096000006 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x06: level 2 translation fault Data abort info: ISV = 0, ISS = 0x00000006 CM = 0, WnR = 0 swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000048633000 [ffff70000b396400] pgd=00000000bfc0d003, p4d=00000000bfc0d003, pud=00000000bfc0c003, pmd=0000000000000000 Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP CPU: 1 PID: 152 Comm: kworker/1:2 Not tainted 6.1.0-rc1-00005-g24c8a1f0fa1e #1 Hardware name: linux,dummy-virt (DT) Workqueue: events free_ipc pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : percpu_counter_add_batch+0x74/0x2e4 lr : percpu_counter_add_batch+0x4c/0x2e4 sp : ffff8000155d7a50 x29: ffff8000155d7a50 x28: 0000000000000000 x27: 0000000000000000 x26: ffff00001635d400 x25: 1fffe0000220f4f3 x24: dfff800000000000 x23: ffff00001635d500 x22: 000000007fffffff x21: 0000000000000000 x20: ffff00001107a740 x19: ffff00001107a798 x18: 0000000000000010 x17: ffff8000093bd524 x16: ffff8000093bdf24 x15: ffff8000081e8528 x14: ffff8000081e9308 x13: ffff80000802aa0c x12: ff80800009632064 x11: 0000000000000000 x10: 0000000000000003 x9 : 1ffff0000b396400 x8 : ffff800059cb2000 x7 : ffff800008948af0 x6 : ffff800008945e20 x5 : ffff000016de8518 x4 : ffff8000093e64f0 x3 : ffff8000082d9058 x2 : 000000007fffffff x1 : ffff80000e6ea340 x0 : 0000000000000001 Call trace: percpu_counter_add_batch+0x74/0x2e4 freeque+0x25c/0x334 free_ipcs+0x12c/0x194 msg_exit_ns+0x48/0x68 free_ipc+0xac/0x230 process_one_work+0x830/0x166c worker_thread+0x8f0/0xff8 kthread+0x25c/0x2e0 ret_from_fork+0x10/0x20 Code: f9400268 d538d089 8b080128 d343fd09 (38f86929) ---[ end trace 0000000000000000 ]--- note: kworker/1:2[152] exited with preempt_count 1 ---------------- Code disassembly (best guess): 0: f9400268 ldr x8, [x19] 4: d538d089 mrs x9, tpidr_el1 8: 8b080128 add x8, x9, x8 c: d343fd09 lsr x9, x8, #3 * 10: 38f86929 ldrsb w9, [x9, x24] <-- trapping instruction
Syzkaller reproducer: # {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false UseTmpDir:false HandleSegv:false Repro:false Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}} unshare(0x48040000) msgget(0x1, 0x2f0)
C reproducer: // autogenerated by syzkaller (https://github.com/google/syzkaller)
#define _GNU_SOURCE
#include <endian.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/syscall.h> #include <sys/types.h> #include <unistd.h>
#ifndef __NR_mmap #define __NR_mmap 222 #endif #ifndef __NR_msgget #define __NR_msgget 186 #endif #ifndef __NR_unshare #define __NR_unshare 97 #endif
int main(void) { syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); syscall(__NR_unshare, 0x48040000ul); syscall(__NR_msgget, 0x798e2634ul, 0x2f0ul); return 0; }
> > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+96e659d35b9d6b541152@syzkaller.appspotmail.com > > Unable to handle kernel paging request at virtual address ffff70000b978a00 > KASAN: maybe wild-memory-access in range [0xffff80005cbc5000-0xffff80005cbc5007] > Mem abort info: > ESR = 0x0000000096000006 > EC = 0x25: DABT (current EL), IL = 32 bits > SET = 0, FnV = 0 > EA = 0, S1PTW = 0 > FSC = 0x06: level 2 translation fault > Data abort info: > ISV = 0, ISS = 0x00000006 > CM = 0, WnR = 0 > swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000045dfb000 > [ffff70000b978a00] pgd=00000000bfbeb003, p4d=00000000bfbeb003, pud=00000000bfbea003, pmd=0000000000000000 > Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP > Modules linked in: > CPU: 0 PID: 2820 Comm: kworker/0:3 Tainted: G W 6.1.0-rc1-syzkaller-00025-gaae703b02f92 #0 > Hardware name: linux,dummy-virt (DT) > Workqueue: events free_ipc > pstate: 10000005 (nzcV daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) > pc : percpu_counter_add_batch+0x78/0x2f0 lib/percpu_counter.c:87 > lr : percpu_counter_add_batch+0x44/0x2f0 lib/percpu_counter.c:87 > sp : ffff8000120979c0 > x29: ffff8000120979c0 x28: ffff0000151ff800 x27: 1fffe00002a3ff24 > x26: ffff80005cbc5000 x25: ffff00000eeac7b0 x24: 1fffe00001dd58f6 > x23: 000000007fffffff x22: ffff80000cc4e800 x21: 0000000000000000 > x20: 0000000000000000 x19: ffff00000eeac758 x18: ffff00006a9cbbc0 > x17: 0000000000000000 x16: 0000000000000000 x15: ffff800008d9c830 > x14: ffff800008d78ecc x13: ffff800008d752d4 x12: ffff600002a3ff01 > x11: 1fffe00002a3ff00 x10: ffff600002a3ff00 x9 : dfff800000000000 > x8 : ffff0000151ff800 x7 : 00000000f1f1f1f1 x6 : dfff800000000000 > x5 : ffff700002412f32 x4 : 1ffff000020ef1ac x3 : 1ffff0000b978a00 > x2 : dfff800000000000 x1 : 0000000000000003 x0 : ffff80005cbc5000 > Call trace: > percpu_counter_add_batch+0x78/0x2f0 lib/percpu_counter.c:87 > percpu_counter_add_local include/linux/percpu_counter.h:75 [inline] > percpu_counter_sub_local include/linux/percpu_counter.h:225 [inline] > freeque+0x20c/0x364 ipc/msg.c:292 > free_ipcs+0xa0/0x160 ipc/namespace.c:125 > msg_exit_ns+0x38/0x60 ipc/msg.c:1334 > free_ipc_ns ipc/namespace.c:138 [inline] > free_ipc+0xd0/0x1c0 ipc/namespace.c:157 > process_one_work+0x780/0x184c kernel/workqueue.c:2289 > worker_thread+0x3cc/0xc40 kernel/workqueue.c:2436 > kthread+0x23c/0x2a0 kernel/kthread.c:376 > ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 > Code: f2fbffe2 92400801 d343fc03 11000c21 (38e26862) > ---[ end trace 0000000000000000 ]--- > ---------------- > Code disassembly (best guess): > 0: f2fbffe2 movk x2, #0xdfff, lsl #48 > 4: 92400801 and x1, x0, #0x7 > 8: d343fc03 lsr x3, x0, #3 > c: 11000c21 add w1, w1, #0x3 > * 10: 38e26862 ldrsb w2, [x3, x2] <-- trapping instruction > > > --- > 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.
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