syzbot

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BUG: KASAN: unknown-crash in instrument_memcpy_before include/linux/instrumented.h:163 [inline]
BUG: KASAN: unknown-crash in copy_mc_to_kernel+0x35/0xa0 arch/x86/lib/copy_mc.c:74
Read of size 4096 at addr ffff8880b0130000 by task syz.6.8872/7135

CPU: 0 UID: 0 PID: 7135 Comm: syz.6.8872 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200
 instrument_memcpy_before include/linux/instrumented.h:163 [inline]
 copy_mc_to_kernel+0x35/0xa0 arch/x86/lib/copy_mc.c:74
 dump_page_copy fs/coredump.c:1321 [inline]
 dump_user_range+0x2e4/0xc70 fs/coredump.c:1372
 elf_core_dump+0x34c2/0x3ad0 fs/binfmt_elf.c:2111
 coredump_write+0x11de/0x1980 fs/coredump.c:1049
 do_coredump fs/coredump.c:1126 [inline]
 vfs_coredump+0x369e/0x4270 fs/coredump.c:1200
 get_signal+0x1107/0x1330 kernel/signal.c:3019
 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:75 [inline]
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline]
 irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline]
 irqentry_exit+0x176/0x620 kernel/entry/common.c:196
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7f2459e514f7
Code: e8 8e fa ff ff 89 f2 48 8d 3d 15 38 1b 00 48 8d 35 01 38 1b 00 31 c0 e8 e7 f8 ff ff 0f 1f 80 00 00 00 00 53 89 fb 48 83 ec 10 <64> 8b 04 25 a4 ff ff ff 85 c0 74 2a 89 fe 31 c0 bf 3c 00 00 00 e8
RSP: 002b:00007f245ae59120 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 000000000000000b RCX: 00007f2459f9acb9
RDX: 00007f245ae59140 RSI: 00007f245ae59270 RDI: 000000000000000b
RBP: 00007f245a008bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f245a216038 R14: 00007f245a215fa0 R15: 00007f245a33fa48
 </TASK>

The buggy address belongs to the physical page:
page: refcount:8 mapcount:6 mapping:0000000000000000 index:0x0 pfn:0xb0130
flags: 0xfff18000000214(referenced|dirty|workingset|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff18000000214 0000000000000000 ffffea0002c04c08 0000000000000000
raw: 0000000000000000 0000000000000000 0000000800000005 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x1029c2(GFP_NOWAIT|__GFP_HIGHMEM|__GFP_IO|__GFP_FS|__GFP_ZERO|__GFP_HARDWALL), pid 32605, tgid 32605 (syz-executor), ts 2152595341659, free_ts 2113225807628
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x228/0x280 mm/page_alloc.c:1884
 prep_new_page mm/page_alloc.c:1892 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3945
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5240
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486
 alloc_frozen_pages_noprof mm/mempolicy.c:2557 [inline]
 alloc_pages_noprof+0xa8/0x190 mm/mempolicy.c:2577
 vm_area_alloc_pages mm/vmalloc.c:3649 [inline]
 __vmalloc_area_node mm/vmalloc.c:3863 [inline]
 __vmalloc_node_range_noprof+0x79b/0x1730 mm/vmalloc.c:4051
 vmalloc_user_noprof+0xad/0xe0 mm/vmalloc.c:4205
 kcov_ioctl+0x55/0x620 kernel/kcov.c:716
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 11495 tgid 11495 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_pages_ok+0xa6b/0xbc0 mm/page_alloc.c:1609
 ptr_ring_cleanup include/linux/ptr_ring.h:680 [inline]
 pfifo_fast_destroy+0x86/0xe0 net/sched/sch_generic.c:896
 __qdisc_destroy+0x153/0x3f0 net/sched/sch_generic.c:1077
 netdev_for_each_tx_queue include/linux/netdevice.h:2680 [inline]
 dev_shutdown+0x93/0x440 net/sched/sch_generic.c:1490
 unregister_netdevice_many_notify+0x11a9/0x2370 net/core/dev.c:12384
 unregister_netdevice_many net/core/dev.c:12459 [inline]
 default_device_exit_batch+0x987/0xa10 net/core/dev.c:13051
 ops_exit_list net/core/net_namespace.c:205 [inline]
 ops_undo_list+0x52b/0x940 net/core/net_namespace.c:252
 cleanup_net+0x4df/0x7b0 net/core/net_namespace.c:696
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340
 worker_thread+0x89f/0xd90 kernel/workqueue.c:3421
 kthread+0x726/0x8b0 kernel/kthread.c:463
 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

Memory state around the buggy address:
 ffff8880b012ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880b012ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880b0130000: 00 16 bb 9a 80 88 ff ff 00 00 00 00 00 00 00 00
                      ^
 ffff8880b0130080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880b0130100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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