[syzbot] memory leak in ext4_mb_new_blocks

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    3dbdb38e Merge branch 'for-5.14' of git://git.kernel.org/p..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11f472e4300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=55ac6a927d7e3fe9
dashboard link: https://syzkaller.appspot.com/bug?extid=d00808b55445133eca1e
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1258bdfc300000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d00808b55445133eca1e@xxxxxxxxxxxxxxxxxxxxxxxxx

BUG: memory leak
unreferenced object 0xffff888113d82958 (size 104):
  comm "kworker/u4:0", pid 8, jiffies 4294943328 (age 340.640s)
  hex dump (first 32 bytes):
    c0 33 c0 13 81 88 ff ff 22 01 00 00 00 00 ad de  .3......".......
    00 01 00 00 00 00 ad de 22 01 00 00 00 00 ad de  ........".......
  backtrace:
    [<ffffffff8176822b>] kmem_cache_zalloc include/linux/slab.h:711 [inline]
    [<ffffffff8176822b>] ext4_mb_pa_alloc fs/ext4/mballoc.c:4974 [inline]
    [<ffffffff8176822b>] ext4_mb_new_blocks+0xd5b/0x18b0 fs/ext4/mballoc.c:5509
    [<ffffffff817238ed>] ext4_ext_map_blocks+0xdfd/0x28f0 fs/ext4/extents.c:4245
    [<ffffffff81746633>] ext4_map_blocks+0x333/0xb10 fs/ext4/inode.c:638
    [<ffffffff8174d632>] mpage_map_one_extent fs/ext4/inode.c:2395 [inline]
    [<ffffffff8174d632>] mpage_map_and_submit_extent fs/ext4/inode.c:2448 [inline]
    [<ffffffff8174d632>] ext4_writepages+0xc82/0x19c0 fs/ext4/inode.c:2800
    [<ffffffff81451c5a>] do_writepages+0x4a/0x120 mm/page-writeback.c:2355
    [<ffffffff815bd0be>] __writeback_single_inode+0x6e/0x520 fs/fs-writeback.c:1610
    [<ffffffff815bdc34>] writeback_sb_inodes+0x2d4/0x710 fs/fs-writeback.c:1875
    [<ffffffff815be0cb>] __writeback_inodes_wb+0x5b/0x150 fs/fs-writeback.c:1944
    [<ffffffff815be5f3>] wb_writeback+0x433/0x4a0 fs/fs-writeback.c:2050
    [<ffffffff815c007a>] wb_check_old_data_flush fs/fs-writeback.c:2152 [inline]
    [<ffffffff815c007a>] wb_do_writeback fs/fs-writeback.c:2205 [inline]
    [<ffffffff815c007a>] wb_workfn+0x3fa/0x760 fs/fs-writeback.c:2234
    [<ffffffff812627d9>] process_one_work+0x2c9/0x610 kernel/workqueue.c:2276
    [<ffffffff812630c9>] worker_thread+0x59/0x5d0 kernel/workqueue.c:2422
    [<ffffffff8126c528>] kthread+0x188/0x1d0 kernel/kthread.c:319
    [<ffffffff810022cf>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

BUG: memory leak
unreferenced object 0xffff888113d82a28 (size 104):
  comm "kworker/u4:0", pid 8, jiffies 4294943328 (age 340.640s)
  hex dump (first 32 bytes):
    d8 08 c1 13 81 88 ff ff 22 01 00 00 00 00 ad de  ........".......
    00 01 00 00 00 00 ad de 22 01 00 00 00 00 ad de  ........".......
  backtrace:
    [<ffffffff8176822b>] kmem_cache_zalloc include/linux/slab.h:711 [inline]
    [<ffffffff8176822b>] ext4_mb_pa_alloc fs/ext4/mballoc.c:4974 [inline]
    [<ffffffff8176822b>] ext4_mb_new_blocks+0xd5b/0x18b0 fs/ext4/mballoc.c:5509
    [<ffffffff817238ed>] ext4_ext_map_blocks+0xdfd/0x28f0 fs/ext4/extents.c:4245
    [<ffffffff81746633>] ext4_map_blocks+0x333/0xb10 fs/ext4/inode.c:638
    [<ffffffff8174d632>] mpage_map_one_extent fs/ext4/inode.c:2395 [inline]
    [<ffffffff8174d632>] mpage_map_and_submit_extent fs/ext4/inode.c:2448 [inline]
    [<ffffffff8174d632>] ext4_writepages+0xc82/0x19c0 fs/ext4/inode.c:2800
    [<ffffffff81451c5a>] do_writepages+0x4a/0x120 mm/page-writeback.c:2355
    [<ffffffff815bd0be>] __writeback_single_inode+0x6e/0x520 fs/fs-writeback.c:1610
    [<ffffffff815bdc34>] writeback_sb_inodes+0x2d4/0x710 fs/fs-writeback.c:1875
    [<ffffffff815be0cb>] __writeback_inodes_wb+0x5b/0x150 fs/fs-writeback.c:1944
    [<ffffffff815be5f3>] wb_writeback+0x433/0x4a0 fs/fs-writeback.c:2050
    [<ffffffff815c007a>] wb_check_old_data_flush fs/fs-writeback.c:2152 [inline]
    [<ffffffff815c007a>] wb_do_writeback fs/fs-writeback.c:2205 [inline]
    [<ffffffff815c007a>] wb_workfn+0x3fa/0x760 fs/fs-writeback.c:2234
    [<ffffffff812627d9>] process_one_work+0x2c9/0x610 kernel/workqueue.c:2276
    [<ffffffff812630c9>] worker_thread+0x59/0x5d0 kernel/workqueue.c:2422
    [<ffffffff8126c528>] kthread+0x188/0x1d0 kernel/kthread.c:319
    [<ffffffff810022cf>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

BUG: memory leak
unreferenced object 0xffff888113d82a90 (size 104):
  comm "kworker/u4:0", pid 8, jiffies 4294943328 (age 340.640s)
  hex dump (first 32 bytes):
    b0 1d c1 13 81 88 ff ff 22 01 00 00 00 00 ad de  ........".......
    00 01 00 00 00 00 ad de 22 01 00 00 00 00 ad de  ........".......
  backtrace:
    [<ffffffff8176822b>] kmem_cache_zalloc include/linux/slab.h:711 [inline]
    [<ffffffff8176822b>] ext4_mb_pa_alloc fs/ext4/mballoc.c:4974 [inline]
    [<ffffffff8176822b>] ext4_mb_new_blocks+0xd5b/0x18b0 fs/ext4/mballoc.c:5509
    [<ffffffff817238ed>] ext4_ext_map_blocks+0xdfd/0x28f0 fs/ext4/extents.c:4245
    [<ffffffff81746633>] ext4_map_blocks+0x333/0xb10 fs/ext4/inode.c:638
    [<ffffffff8174d632>] mpage_map_one_extent fs/ext4/inode.c:2395 [inline]
    [<ffffffff8174d632>] mpage_map_and_submit_extent fs/ext4/inode.c:2448 [inline]
    [<ffffffff8174d632>] ext4_writepages+0xc82/0x19c0 fs/ext4/inode.c:2800
    [<ffffffff81451c5a>] do_writepages+0x4a/0x120 mm/page-writeback.c:2355
    [<ffffffff815bd0be>] __writeback_single_inode+0x6e/0x520 fs/fs-writeback.c:1610
    [<ffffffff815bdc34>] writeback_sb_inodes+0x2d4/0x710 fs/fs-writeback.c:1875
    [<ffffffff815be0cb>] __writeback_inodes_wb+0x5b/0x150 fs/fs-writeback.c:1944
    [<ffffffff815be5f3>] wb_writeback+0x433/0x4a0 fs/fs-writeback.c:2050
    [<ffffffff815c007a>] wb_check_old_data_flush fs/fs-writeback.c:2152 [inline]
    [<ffffffff815c007a>] wb_do_writeback fs/fs-writeback.c:2205 [inline]
    [<ffffffff815c007a>] wb_workfn+0x3fa/0x760 fs/fs-writeback.c:2234
    [<ffffffff812627d9>] process_one_work+0x2c9/0x610 kernel/workqueue.c:2276
    [<ffffffff812630c9>] worker_thread+0x59/0x5d0 kernel/workqueue.c:2422
    [<ffffffff8126c528>] kthread+0x188/0x1d0 kernel/kthread.c:319
    [<ffffffff810022cf>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

BUG: memory leak
unreferenced object 0xffff888123294558 (size 1176):
  comm "syz-executor.1", pid 8467, jiffies 4294969731 (age 76.670s)
  hex dump (first 32 bytes):
    0a f3 00 00 04 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff81794e19>] ext4_alloc_inode+0x19/0x1a0 fs/ext4/super.c:1281
    [<ffffffff81598827>] alloc_inode+0x27/0x100 fs/inode.c:233
    [<ffffffff81598923>] new_inode_pseudo fs/inode.c:934 [inline]
    [<ffffffff81598923>] new_inode+0x23/0x100 fs/inode.c:963
    [<ffffffff81735ce7>] __ext4_new_inode+0x127/0x26d0 fs/ext4/ialloc.c:958
    [<ffffffff8177c2bf>] ext4_mkdir+0x1ef/0x550 fs/ext4/namei.c:2921
    [<ffffffff8157b7a8>] vfs_mkdir+0x258/0x330 fs/namei.c:3813
    [<ffffffff81582155>] do_mkdirat+0x1a5/0x1f0 fs/namei.c:3838
    [<ffffffff8439b235>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    [<ffffffff8439b235>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
    [<ffffffff84400068>] entry_SYSCALL_64_after_hwframe+0x44/0xae

[  401.478399][    C


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