Messages in this thread Patch in this message | | | Date | Sat, 4 Jan 2003 03:35:10 +0100 (MET) | From | Mikael Pettersson <> | Subject | [PATCH] 2.5.54 fix ide-cd/ide-scsi oopses after module unload |
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In 2.5 (the bug's been there since 2.5.42), rmmod:ing a modular IDE subdriver like ide-cd or ide-scsi and then rebooting causes an oops in device_shutdown(). This is because the IDE layer doesn't reset the drive->gendev.driver pointer that it previously set up to point to data structures in the subdriver module. device_shutdown() sees a non-NULL ->driver, dereferences it, and oopses.
The patch below for 2.5.54 fixes two generic bugs related to unloading of modular IDE subdrivers, and one specific to ide-scsi:
1. ata_attach() needs to set drive->gendev.driver = NULL when no specific driver claims the drive. This prevents a drive previously owned by a subdriver module from keeping its ->gendev.driver pointing into that module.
2. ide_unregister_driver() needs to unregister &driver->gen_driver; this is to balance the corresponding register call in ide_register_driver(). [This part of the patch is originally by Patrick Mochel.]
3. ide-scsi.c abuses ide_driver_t's busy field as a counter while the field in fact is a single-bit boolean. This causes the busyness of the driver to be incorrect while the driver is active. (From my recent patch for 2.4.20-ac2/2.4.21-pre2.)
With these three fixes modular ide-cd and ide-scsi work quite reliably for me in 2.5.54.
/Mikael
diff -ruN linux-2.5.54/drivers/ide/ide.c linux-2.5.54.ide-fixes/drivers/ide/ide.c --- linux-2.5.54/drivers/ide/ide.c 2003-01-02 14:27:55.000000000 +0100 +++ linux-2.5.54.ide-fixes/drivers/ide/ide.c 2003-01-04 02:34:02.000000000 +0100 @@ -1346,6 +1346,7 @@ spin_unlock(&drivers_lock); spin_lock(&drives_lock); list_add_tail(&drive->list, &ata_unused); + drive->gendev.driver = NULL; spin_unlock(&drives_lock); return 1; } @@ -2308,6 +2309,8 @@ list_del(&driver->drivers); spin_unlock(&drivers_lock); + driver_unregister(&driver->gen_driver); + while(!list_empty(&driver->drives)) { drive = list_entry(driver->drives.next, ide_drive_t, list); if (driver->cleanup(drive)) { diff -ruN linux-2.5.54/drivers/scsi/ide-scsi.c linux-2.5.54.ide-fixes/drivers/scsi/ide-scsi.c --- linux-2.5.54/drivers/scsi/ide-scsi.c 2002-12-24 13:53:50.000000000 +0100 +++ linux-2.5.54.ide-fixes/drivers/scsi/ide-scsi.c 2003-01-04 02:34:02.000000000 +0100 @@ -590,6 +590,7 @@ set_bit(IDESCSI_LOG_CMD, &scsi->log); #endif /* IDESCSI_DEBUG_LOG */ idescsi_add_settings(drive); + DRIVER(drive)->busy--; } static int idescsi_cleanup (ide_drive_t *drive) @@ -995,7 +996,7 @@ for (id = 0; id < MAX_HWIFS * MAX_DRIVES; id++) { drive = idescsi_drives[id]; if (drive) - DRIVER(drive)->busy--; + DRIVER(drive)->busy = 0; } scsi_unregister (idescsi_host); device_unregister(&idescsi_primary); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.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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