Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 UID: 0 PID: 13703 Comm: syz.4.1984 Not tainted 6.16.0-rc3-next-20250623-syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:pidfs_free_pid+0xaf/0x140 fs/pidfs.c:162
Code: f0 ff ff 73 e4 43 80 3c 3c 00 74 08 4c 89 f7 e8 a7 1b de ff 49 83 3e 00 0f 85 84 00 00 00 e8 08 f2 79 ff 48 89 d8 48 c1 e8 03 <42> 80 3c 38 00 74 08 48 89 df e8 82 1b de ff 4c 8b 33 4d 85 f6 74
RSP: 0018:ffffc90000007b90 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff888025ce3c00
RDX: 0000000000000100 RSI: 0000000000000001 RDI: ffff8880244816f0
RBP: 0000000000000001 R08: ffff888024481683 R09: 1ffff110048902d0
R10: dffffc0000000000 R11: ffffed10048902d1 R12: 1ffff110048902dd
R13: ffffffff81a83684 R14: ffff8880244816e8 R15: dffffc0000000000
FS: 00007fdf978ab6c0(0000) GS:ffff888125c25000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000cf3030 CR3: 000000005213c000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 00000000000000d8
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
put_pid+0x9c/0x130 kernel/pid.c:103
rcu_do_batch kernel/rcu/tree.c:2582 [inline]
rcu_core+0xca5/0x1710 kernel/rcu/tree.c:2838
handle_softirqs+0x283/0x870 kernel/softirq.c:579
__do_softirq kernel/softirq.c:613 [inline]
invoke_softirq kernel/softirq.c:453 [inline]
__irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:clear_page_erms+0xb/0x20 arch/x86/lib/clear_page_64.S:52
Code: 48 8d 7f 40 75 d9 90 e9 c3 10 04 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa b9 00 10 00 00 31 c0 aa c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000bc2e3f0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000d40
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888055df42c0
RBP: 1ffffffff1b75e87 R08: ffffffff8fa18cf7 R09: 0000000000000000
R10: ffffed100abbe800 R11: fffffbfff1f4319f R12: fffa800055df4000
R13: fffa800000000000 R14: 1ffffffff1b75e85 R15: 0000000000000001
clear_page arch/x86/include/asm/page_64.h:54 [inline]
clear_highpage_kasan_tagged include/linux/highmem.h:248 [inline]
kernel_init_pages mm/page_alloc.c:1228 [inline]
post_alloc_hook+0x1bd/0x2a0 mm/page_alloc.c:1846
prep_new_page mm/page_alloc.c:1856 [inline]
get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3855
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5145
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2438
shmem_alloc_folio mm/shmem.c:1847 [inline]
shmem_alloc_and_add_folio+0x447/0xf60 mm/shmem.c:1886
shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2532
shmem_get_folio mm/shmem.c:2638 [inline]
shmem_write_begin+0xf7/0x2b0 mm/shmem.c:3288
generic_perform_write+0x2c7/0x910 mm/filemap.c:4175
shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3463
__kernel_write_iter+0x393/0x860 fs/read_write.c:619
dump_emit_page fs/coredump.c:1295 [inline]
dump_user_range+0x8a0/0xc90 fs/coredump.c:1369
elf_core_dump+0x32ed/0x3900 fs/binfmt_elf.c:2075
coredump_write+0x1169/0x1900 fs/coredump.c:1048
vfs_coredump+0x1a4b/0x2ab0 fs/coredump.c:1167
get_signal+0x1109/0x1340 kernel/signal.c:3019
arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:111
exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdf9698e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fdf978ab0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 00000000000000ca RBX: 00007fdf96bb5fa8 RCX: 00007fdf9698e929
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fdf96bb5fac
RBP: 00007fdf96bb5fa0 R08: 7fffffffffffffff R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fdf96bb5fac
R13: 0000000000000000 R14: 00007ffeb0c46510 R15: 00007ffeb0c465f8
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:pidfs_free_pid+0xaf/0x140 fs/pidfs.c:162
Code: f0 ff ff 73 e4 43 80 3c 3c 00 74 08 4c 89 f7 e8 a7 1b de ff 49 83 3e 00 0f 85 84 00 00 00 e8 08 f2 79 ff 48 89 d8 48 c1 e8 03 <42> 80 3c 38 00 74 08 48 89 df e8 82 1b de ff 4c 8b 33 4d 85 f6 74
RSP: 0018:ffffc90000007b90 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff888025ce3c00
RDX: 0000000000000100 RSI: 0000000000000001 RDI: ffff8880244816f0
RBP: 0000000000000001 R08: ffff888024481683 R09: 1ffff110048902d0
R10: dffffc0000000000 R11: ffffed10048902d1 R12: 1ffff110048902dd
R13: ffffffff81a83684 R14: ffff8880244816e8 R15: dffffc0000000000
FS: 00007fdf978ab6c0(0000) GS:ffff888125c25000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000cf3030 CR3: 000000005213c000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 00000000000000d8
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: f0 ff lock (bad)
2: ff 73 e4 push -0x1c(%rbx)
5: 43 80 3c 3c 00 cmpb $0x0,(%r12,%r15,1)
a: 74 08 je 0x14
c: 4c 89 f7 mov %r14,%rdi
f: e8 a7 1b de ff call 0xffde1bbb
14: 49 83 3e 00 cmpq $0x0,(%r14)
18: 0f 85 84 00 00 00 jne 0xa2
1e: e8 08 f2 79 ff call 0xff79f22b
23: 48 89 d8 mov %rbx,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) <-- trapping instruction
2f: 74 08 je 0x39
31: 48 89 df mov %rbx,%rdi
34: e8 82 1b de ff call 0xffde1bbb
39: 4c 8b 33 mov (%rbx),%r14
3c: 4d 85 f6 test %r14,%r14
3f: 74 .byte 0x74