syzbot

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BUG: KCSAN: data-race in do_madvise / zap_page_range_single

write to 0xffff888101bbfaf0 of 8 bytes by task 8446 on cpu 0:
 update_hiwater_rss include/linux/mm.h:1946 [inline]
 madvise_free_single_vma mm/madvise.c:727 [inline]
 madvise_dontneed_free mm/madvise.c:819 [inline]
 madvise_vma mm/madvise.c:948 [inline]
 do_madvise+0xa80/0x1480 mm/madvise.c:1144
 __do_sys_madvise mm/madvise.c:1170 [inline]
 __se_sys_madvise mm/madvise.c:1168 [inline]
 __x64_sys_madvise+0x5d/0x70 mm/madvise.c:1168
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888101bbfaf0 of 8 bytes by task 1658 on cpu 1:
 update_hiwater_rss include/linux/mm.h:1945 [inline]
 zap_page_range_single+0x11e/0x220 mm/memory.c:1554
 unmap_mapping_range_vma mm/memory.c:3141 [inline]
 unmap_mapping_range_tree mm/memory.c:3162 [inline]
 unmap_mapping_pages+0x159/0x1a0 mm/memory.c:3194
 collapse_file+0xb3e/0x2100 mm/khugepaged.c:1811
 khugepaged_scan_file mm/khugepaged.c:2024 [inline]
 khugepaged_scan_mm_slot mm/khugepaged.c:2120 [inline]
 khugepaged_do_scan+0x1255/0x15b0 mm/khugepaged.c:2206
 khugepaged+0x75/0x650 mm/khugepaged.c:2251
 kthread+0x1fa/0x220 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1658 Comm: khugepaged Not tainted 5.10.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 1658 Comm: khugepaged Not tainted 5.10.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x116/0x15d lib/dump_stack.c:118
 panic+0x1e7/0x5fa kernel/panic.c:231
 kcsan_report+0x67b/0x680 kernel/kcsan/report.c:634
 kcsan_setup_watchpoint+0x46a/0x4d0 kernel/kcsan/core.c:568
 update_hiwater_rss include/linux/mm.h:1945 [inline]
 zap_page_range_single+0x11e/0x220 mm/memory.c:1554
 unmap_mapping_range_vma mm/memory.c:3141 [inline]
 unmap_mapping_range_tree mm/memory.c:3162 [inline]
 unmap_mapping_pages+0x159/0x1a0 mm/memory.c:3194
 collapse_file+0xb3e/0x2100 mm/khugepaged.c:1811
 khugepaged_scan_file mm/khugepaged.c:2024 [inline]
 khugepaged_scan_mm_slot mm/khugepaged.c:2120 [inline]
 khugepaged_do_scan+0x1255/0x15b0 mm/khugepaged.c:2206
 khugepaged+0x75/0x650 mm/khugepaged.c:2251
 kthread+0x1fa/0x220 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Kernel Offset: disabled
Rebooting in 86400 seconds..