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 ffff8880aa548000 by task syz.7.7465/28273

CPU: 0 UID: 0 PID: 28273 Comm: syz.7.7465 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
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:1322 [inline]
 dump_user_range+0x31a/0x12d0 fs/coredump.c:1373
 elf_core_dump+0x34c2/0x3ad0 fs/binfmt_elf.c:2111
 coredump_write+0x1224/0x1960 fs/coredump.c:1050
 do_coredump fs/coredump.c:1127 [inline]
 vfs_coredump+0x36af/0x4280 fs/coredump.c:1201
 get_signal+0x10d7/0x1310 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: 0033:0x7fe602a6bf81
Code: 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f
RSP: 002b:fffffffffffffe70 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007fe602ce5fa0 RCX: 00007fe602a6bf79
RDX: 0000000000000000 RSI: fffffffffffffe70 RDI: 0000000000008000
RBP: 00007fe602b027e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007fe602ce6038 R14: 00007fe602ce5fa0 R15: 00007fffca7d23d8
 </TASK>

The buggy address belongs to the physical page:
page: refcount:7 mapcount:5 mapping:0000000000000000 index:0x0 pfn:0xaa548
flags: 0x80000000000000(node=0|zone=1)
raw: 0080000000000000 ffffea0002a95208 ffffea0002a95208 0000000000000000
raw: 0000000000000000 0000000000000000 0000000700000004 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 0x29c2(GFP_NOWAIT|__GFP_HIGHMEM|__GFP_IO|__GFP_FS|__GFP_ZERO), pid 24777, tgid 24777 (syz-executor), ts 1428328264450, free_ts 0
 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+0x28bb/0x2950 mm/page_alloc.c:3945
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5240
 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2486
 alloc_frozen_pages_noprof mm/mempolicy.c:2557 [inline]
 alloc_pages_noprof+0xce/0x1e0 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+0x58/0x640 kernel/kcov.c:716
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xff/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_owner free stack trace missing

Memory state around the buggy address:
 ffff8880aa547f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880aa547f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880aa548000: 00 d3 c3 32 80 88 ff ff 00 00 00 00 00 00 00 00
                      ^
 ffff8880aa548080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880aa548100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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