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Date:   Mon, 24 Apr 2023 00:19:45 -0700
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Subject: [syzbot] [ext4?] KCSAN: data-race in __es_find_extent_range /
 __es_find_extent_range (6)
From:   syzbot <syzbot+4a03518df1e31b537066@syzkaller.appspotmail.com>
To:     adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        syzkaller-bugs@googlegroups.com, tytso@mit.edu
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Hello,

syzbot found the following issue on:

HEAD commit:    44149752e998 Merge tag 'cgroup-for-6.3-rc6-fixes' of git:/..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=100db37bc80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=710057cbb8def08c
dashboard link: https://syzkaller.appspot.com/bug?extid=4a03518df1e31b537066
compiler:       Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7bfa303f05cc/disk-44149752.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4e8ea8730409/vmlinux-44149752.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e584bce13ba7/bzImage-44149752.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4a03518df1e31b537066@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __es_find_extent_range / __es_find_extent_range

write to 0xffff88810a5a98a8 of 8 bytes by task 10666 on cpu 0:
 __es_find_extent_range+0x212/0x300 fs/ext4/extents_status.c:296
 ext4_es_find_extent_range+0x91/0x260 fs/ext4/extents_status.c:318
 ext4_ext_put_gap_in_cache fs/ext4/extents.c:2284 [inline]
 ext4_ext_map_blocks+0x120d/0x36c0 fs/ext4/extents.c:4191
 ext4_map_blocks+0x2a0/0x1050 fs/ext4/inode.c:576
 ext4_mpage_readpages+0x699/0x1440 fs/ext4/readpage.c:300
 ext4_read_folio+0xc5/0x1a0 fs/ext4/inode.c:3308
 filemap_read_folio+0x2c/0x100 mm/filemap.c:2424
 filemap_fault+0x66f/0xb20 mm/filemap.c:3367
 __do_fault mm/memory.c:4155 [inline]
 do_read_fault mm/memory.c:4506 [inline]
 do_fault mm/memory.c:4635 [inline]
 handle_pte_fault mm/memory.c:4923 [inline]
 __handle_mm_fault mm/memory.c:5065 [inline]
 handle_mm_fault+0x115d/0x21d0 mm/memory.c:5211
 faultin_page mm/gup.c:925 [inline]
 __get_user_pages+0x363/0xc30 mm/gup.c:1147
 populate_vma_page_range mm/gup.c:1543 [inline]
 __mm_populate+0x23a/0x360 mm/gup.c:1652
 mm_populate include/linux/mm.h:3026 [inline]
 vm_mmap_pgoff+0x174/0x210 mm/util.c:547
 ksys_mmap_pgoff+0x2ac/0x320 mm/mmap.c:1410
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88810a5a98a8 of 8 bytes by task 10630 on cpu 1:
 __es_find_extent_range+0x79/0x300 fs/ext4/extents_status.c:270
 __es_scan_range fs/ext4/extents_status.c:345 [inline]
 __es_scan_clu fs/ext4/extents_status.c:399 [inline]
 ext4_es_scan_clu+0xe4/0x190 fs/ext4/extents_status.c:415
 ext4_insert_delayed_block fs/ext4/inode.c:1694 [inline]
 ext4_da_map_blocks fs/ext4/inode.c:1806 [inline]
 ext4_da_get_block_prep+0x575/0xa70 fs/ext4/inode.c:1870
 __block_write_begin_int+0x349/0xe50 fs/buffer.c:2034
 __block_write_begin+0x5e/0x110 fs/buffer.c:2084
 ext4_da_write_begin+0x2fa/0x610 fs/ext4/inode.c:3084
 generic_perform_write+0x1c3/0x3d0 mm/filemap.c:3926
 ext4_buffered_write_iter+0x234/0x3e0 fs/ext4/file.c:289
 ext4_file_write_iter+0xd7/0x10e0
 call_write_iter include/linux/fs.h:1851 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x463/0x760 fs/read_write.c:584
 ksys_write+0xeb/0x1a0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0xffff88810a653dc0 -> 0xffff8881067334d8

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 10630 Comm: syz-executor.0 Not tainted 6.3.0-rc6-syzkaller-00138-g44149752e998 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023
==================================================================


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