[BUG] "held lock freed!" on 2.6.18-rc4-gc4e321b8, not reproducible

From: Markus Dahms
Date: Fri Aug 11 2006 - 04:42:15 EST


I got the following bug on 2.6.18-rc4+ after booting but could not
reproduce it. So it may be a race condition or just a hardware bug.

GIT c4e321b85a89d7cd392d3105b2c033a6c58ed337 from .../gregkh/linux-2.6
Hardware: AMD K7 1.8GHz, VIA chipset, PATA... - some time old

Except the bug message the machine runs normally..


EXT3-fs: mounted filesystem with ordered data mode.
input: AT Translated Set 2 keyboard as /class/input/input0
VFS: Mounted root (ext3 filesystem) readonly.
Freeing unused kernel memory: 192k freed
Write protecting the kernel read-only data: 275k

[ BUG: held lock freed! ]
mount/320 is freeing memory c1796c20-c1796c5f, with a lock still held there!
(&sbinfo->stat_lock){--..}, at: [<c015e9f8>] shmem_get_inode+0x28/0x1d0
2 locks held by mount/320:
#0: (&type->s_umount_key#8){--..}, at: [<c016ce6f>] sget+0x15f/0x370
#1: (&sbinfo->stat_lock){--..}, at: [<c015e9f8>] shmem_get_inode+0x28/0x1d0

stack backtrace:
[<c010562b>] show_trace+0x1b/0x20
[<c0105656>] dump_stack+0x26/0x30
[<c0137989>] debug_check_no_locks_freed+0x189/0x190
[<c0161f95>] kfree+0x55/0xc0
[<c0181c2c>] free_fdtable_rcu+0xdc/0x130
[<c012d7d0>] __rcu_process_callbacks+0x80/0x1b0
[<c012d912>] rcu_process_callbacks+0x12/0x30
[<c01209ee>] tasklet_action+0x4e/0x90
[<c0121158>] __do_softirq+0x58/0xe0
[<c01059b4>] do_softirq+0x64/0xf0
[<c0121016>] irq_exit+0x36/0x40
[<c0105aef>] do_IRQ+0xaf/0x110
[<c0103a2d>] common_interrupt+0x25/0x2c
[<c02cd71b>] _spin_lock+0x3b/0x50
[<c015e9f8>] shmem_get_inode+0x28/0x1d0
[<c015ecf0>] shmem_fill_super+0x150/0x1a0
[<c016d19a>] get_sb_nodev+0x5a/0xb0
[<c015df6e>] shmem_get_sb+0x2e/0x30
[<c016c7bd>] vfs_kern_mount+0x4d/0x90
[<c016c86f>] do_kern_mount+0x3f/0x60
[<c0183b3d>] do_mount+0x29d/0x660
[<c0183f8c>] sys_mount+0x8c/0xd0
[<c010303f>] syscall_call+0x7/0xb

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