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Date: Mon, 07 Jun 2010 08:20:30 +0300 From: Jari Ruusu <jariruusu@...rs.sourceforge.net> To: linux-kernel@...r.kernel.org CC: Rusty Russell <rusty@...tcorp.com.au>, Al Viro <viro@...iv.linux.org.uk>, Linus Torvalds <torvalds@...ux-foundation.org> Subject: 2.6.35-rc2 module reference counting broken Someone broke block device module reference counting. Problem occours when a modular block device is mounted and unmounted. Not when it is directly read. 2.6.34 kernel works OK, but 2.6.35-rc2 kernel seems to increase usage count by one for each mount + umount pair. # uname -s -r -m Linux 2.6.35-rc2 i686 # grep CONFIG_SMP /usr/src/linux-2.6.35-rc2/.config # CONFIG_SMP is not set # grep CONFIG_MODULE_UNLOAD /usr/src/linux-2.6.35-rc2/.config CONFIG_MODULE_UNLOAD=y # grep CONFIG_BLK_DEV_FD /usr/src/linux-2.6.35-rc2/.config CONFIG_BLK_DEV_FD=m # lsmod Module Size Used by # modprobe floppy # lsmod Module Size Used by floppy 40029 0 # mount -t ext2 /dev/fd0 /mnt # umount /mnt # lsmod Module Size Used by floppy 40029 1 # rmmod floppy ERROR: Module floppy is in use # echo $? 1 # (reboot) # uname -s -r -m Linux 2.6.35-rc2 i686 # lsmod Module Size Used by # modprobe floppy # lsmod Module Size Used by floppy 40029 0 # dd if=/dev/fd0 of=/dev/null bs=4096 count=1 conv=notrunc 2>/dev/null # lsmod Module Size Used by floppy 40029 0 # rmmod floppy # echo $? 0 # lsmod Module Size Used by # -- Jari Ruusu 1024R/3A220F51 5B 4B F9 BB D3 3F 52 E9 DB 1D EB E3 24 0E A9 DD -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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