user/sven/linux.git/block/genhd.c, branch v3.2.29

block: fix buffer overflow when printing partition UUIDs

2012-05-30T23:43:15Z

commit 05c69d298c96703741cac9a5cbbf6c53bd55a6e2 upstream. 6d1d8050b4bc8 "block, partition: add partition_meta_info to hd_struct" added part_unpack_uuid() which assumes that the passed in buffer has enough space for sprintfing "%pU" - 37 characters including '\0'. Unfortunately, b5af921ec0233 "init: add support for root devices specified by partition UUID" supplied 33 bytes buffer to the function leading to the following panic with stackprotector enabled. Kernel panic - not syncing: stack-protector: Kernel stack corrupted in: ffffffff81b14c7e [] panic+0xba/0x1c6 [] ? printk_all_partitions+0x259/0x26xb [] __stack_chk_fail+0x1b/0x20 [] printk_all_paritions+0x259/0x26xb [] mount_block_root+0x1bc/0x27f [] mount_root+0x57/0x5b [] prepare_namespace+0x13d/0x176 [] ? release_tgcred.isra.4+0x330/0x30 [] kernel_init+0x155/0x15a [] ? schedule_tail+0x27/0xb0 [] kernel_thread_helper+0x5/0x10 [] ? start_kernel+0x3c5/0x3c5 [] ? gs_change+0x13/0x13 Increase the buffer size, remove the dangerous part_unpack_uuid() and use snprintf() directly from printk_all_partitions(). Signed-off-by: Tejun Heo Reported-by: Szymon Gruszczynski Cc: Will Drewry Signed-off-by: Jens Axboe Signed-off-by: Ben Hutchings

Block: use a freezable workqueue for disk-event polling

2012-03-19T16:02:34Z

commit 62d3c5439c534b0e6c653fc63e6d8c67be3a57b1 upstream. This patch (as1519) fixes a bug in the block layer's disk-events polling. The polling is done by a work routine queued on the system_nrt_wq workqueue. Since that workqueue isn't freezable, the polling continues even in the middle of a system sleep transition. Obviously, polling a suspended drive for media changes and such isn't a good thing to do; in the case of USB mass-storage devices it can lead to real problems requiring device resets and even re-enumeration. The patch fixes things by creating a new system-wide, non-reentrant, freezable workqueue and using it for disk-events polling. Signed-off-by: Alan Stern Acked-by: Tejun Heo Acked-by: Rafael J. Wysocki Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

block: fix __blkdev_get and add_disk race condition

2012-03-19T16:02:34Z

commit 9f53d2fe815b4011ff930a7b6db98385d45faa68 upstream. The following situation might occur: __blkdev_get: add_disk: register_disk() get_gendisk() disk_block_events() disk->ev == NULL disk_add_events() __disk_unblock_events() disk->ev != NULL --ev->block Then we unblock events, when they are suppose to be blocked. This can trigger events related block/genhd.c warnings, but also can crash in sd_check_events() or other places. I'm able to reproduce crashes with the following scripts (with connected usb dongle as sdb disk). DEV=/dev/sdb ENABLE=/sys/bus/usb/devices/1-2/bConfigurationValue function stop_me() { for i in `jobs -p` ; do kill $i 2> /dev/null ; done exit } trap stop_me SIGHUP SIGINT SIGTERM for ((i = 0; i < 10; i++)) ; do while true; do fdisk -l $DEV 2>&1 > /dev/null ; done & done while true ; do echo 1 > $ENABLE sleep 1 echo 0 > $ENABLE done I use the script to verify patch fixing oops in sd_revalidate_disk http://marc.info/?l=linux-scsi&m=132935572512352&w=2 Without Jun'ichi Nomura patch titled "Fix NULL pointer dereference in sd_revalidate_disk" or this one, script easily crash kernel within a few seconds. With both patches applied I do not observe crash. Unfortunately after some time (dozen of minutes), script will hung in: [ 1563.906432] [] schedule_timeout_uninterruptible+0x15/0x20 [ 1563.906437] [] msleep+0x15/0x20 [ 1563.906443] [] blk_drain_queue+0x32/0xd0 [ 1563.906447] [] blk_cleanup_queue+0xd0/0x170 [ 1563.906454] [] scsi_free_queue+0x3f/0x60 [ 1563.906459] [] __scsi_remove_device+0x6e/0xb0 [ 1563.906463] [] scsi_forget_host+0x4f/0x60 [ 1563.906468] [] scsi_remove_host+0x5a/0xf0 [ 1563.906482] [] quiesce_and_remove_host+0x5b/0xa0 [usb_storage] [ 1563.906490] [] usb_stor_disconnect+0x13/0x20 [usb_storage] Anyway I think this patch is some step forward. As drawback, I do not teardown on sysfs file create error, because I do not know how to nullify disk->ev (since it can be used). However add_disk error handling practically does not exist too, and things will work without this sysfs file, except events will not be exported to user space. Signed-off-by: Stanislaw Gruszka Acked-by: Tejun Heo Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

block: Revert "[SCSI] genhd: add a new attribute "alias" in gendisk"

2011-11-10T08:03:55Z

This reverts commit a72c5e5eb738033938ab30d6a634b74d1d060f10. The commit introduced alias for block devices which is intended to be used during logging although actual usage hasn't been committed yet. This approach adds very limited benefit (raw log might be easier to follow) which can be trivially implemented in userland but has a lot of problems. It is much worse than netif renames because it doesn't rename the actual device but just adds conveninence name which isn't used universally or enforced. Everything internal including device lookup and sysfs still uses the internal name and nothing prevents two devices from using conflicting alias - ie. sda can have sdb as its alias. This has been nacked by people working on device driver core, block layer and kernel-userland interface and shouldn't have been upstreamed. Revert it. http://thread.gmane.org/gmane.linux.kernel/1155104 http://thread.gmane.org/gmane.linux.scsi/68632 http://thread.gmane.org/gmane.linux.scsi/69776 Signed-off-by: Tejun Heo Acked-by: Greg Kroah-Hartman Acked-by: Kay Sievers Cc: "James E.J. Bottomley" Cc: Nao Nishijima Cc: Alan Cox Cc: Al Viro Signed-off-by: Jens Axboe

Merge branch 'for-3.2/drivers' of git://git.kernel.dk/linux-block

2011-11-05T00:22:14Z

* 'for-3.2/drivers' of git://git.kernel.dk/linux-block: (30 commits) virtio-blk: use ida to allocate disk index hpsa: add small delay when using PCI Power Management to reset for kump cciss: add small delay when using PCI Power Management to reset for kump xen/blkback: Fix two races in the handling of barrier requests. xen/blkback: Check for proper operation. xen/blkback: Fix the inhibition to map pages when discarding sector ranges. xen/blkback: Report VBD_WSECT (wr_sect) properly. xen/blkback: Support 'feature-barrier' aka old-style BARRIER requests. xen-blkfront: plug device number leak in xlblk_init() error path xen-blkfront: If no barrier or flush is supported, use invalid operation. xen-blkback: use kzalloc() in favor of kmalloc()+memset() xen-blkback: fixed indentation and comments xen-blkfront: fix a deadlock while handling discard response xen-blkfront: Handle discard requests. xen-blkback: Implement discard requests ('feature-discard') xen-blkfront: add BLKIF_OP_DISCARD and discard request struct drivers/block/loop.c: remove unnecessary bdev argument from loop_clr_fd() drivers/block/loop.c: emit uevent on auto release drivers/block/cpqarray.c: use pci_dev->revision loop: always allow userspace partitions and optionally support automatic scanning ... Fic up trivial header file includsion conflict in drivers/block/loop.c

Merge branch 'for-3.2/core' of git://git.kernel.dk/linux-block

2011-11-05T00:06:58Z

* 'for-3.2/core' of git://git.kernel.dk/linux-block: (29 commits) block: don't call blk_drain_queue() if elevator is not up blk-throttle: use queue_is_locked() instead of lockdep_is_held() blk-throttle: Take blkcg->lock while traversing blkcg->policy_list blk-throttle: Free up policy node associated with deleted rule block: warn if tag is greater than real_max_depth. block: make gendisk hold a reference to its queue blk-flush: move the queue kick into blk-flush: fix invalid BUG_ON in blk_insert_flush block: Remove the control of complete cpu from bio. block: fix a typo in the blk-cgroup.h file block: initialize the bounce pool if high memory may be added later block: fix request_queue lifetime handling by making blk_queue_cleanup() properly shutdown block: drop @tsk from attempt_plug_merge() and explain sync rules block: make get_request[_wait]() fail if queue is dead block: reorganize throtl_get_tg() and blk_throtl_bio() block: reorganize queue draining block: drop unnecessary blk_get/put_queue() in scsi_cmd_ioctl() and blk_get_tg() block: pass around REQ_* flags instead of broken down booleans during request alloc/free block: move blk_throtl prototypes to block/blk.h block: fix genhd refcounting in blkio_policy_parse_and_set() ... Fix up trivial conflicts due to "mddev_t" -> "struct mddev" conversion and making the request functions be of type "void" instead of "int" in - drivers/md/{faulty.c,linear.c,md.c,md.h,multipath.c,raid0.c,raid1.c,raid10.c,raid5.c} - drivers/staging/zram/zram_drv.c

block: make gendisk hold a reference to its queue

2011-10-19T12:31:07Z

The following command sequence triggers an oops. # mount /dev/sdb1 /mnt # echo 1 > /sys/class/scsi_device/0\:0\:1\:0/device/delete # umount /mnt general protection fault: 0000 [#1] PREEMPT SMP CPU 2 Modules linked in: Pid: 791, comm: umount Not tainted 3.1.0-rc3-work+ #8 Bochs Bochs RIP: 0010:[] [] __lock_acquire+0x389/0x1d60 ... Call Trace: [] lock_acquire+0x95/0x140 [] _raw_spin_lock+0x3b/0x50 [] bdi_lock_two+0x5c/0x70 [] bdev_inode_switch_bdi+0x4c/0xf0 [] __blkdev_put+0x11b/0x1d0 [] __blkdev_put+0x160/0x1d0 [] blkdev_put+0x5f/0x190 [] kill_block_super+0x4d/0x80 [] deactivate_locked_super+0x45/0x70 [] deactivate_super+0x4a/0x70 [] mntput_no_expire+0xed/0x130 [] sys_umount+0x7e/0x3a0 [] system_call_fastpath+0x16/0x1b This is because bdev holds on to disk but disk doesn't pin the associated queue. If a SCSI device is removed while the device is still open, the sdev puts the base reference to the queue on release. When the bdev is finally released, the associated queue is already gone along with the bdi and bdev_inode_switch_bdi() ends up dereferencing already freed bdi. Even if it were not for this bug, disk not holding onto the associated queue is very unusual and error-prone. Fix it by making add_disk() take an extra reference to its queue and put it on disk_release() and ensuring that disk and its fops owner are put in that order after all accesses to the disk and queue are complete. Signed-off-by: Tejun Heo Cc: stable@kernel.org Signed-off-by: Jens Axboe

[SCSI] genhd: add a new attribute "alias" in gendisk

2011-08-29T07:16:19Z

This patch allows the user to set an "alias" of the disk via sysfs interface. This patch only adds a new attribute "alias" in gendisk structure. To show the alias instead of the device name in kernel messages, we need to revise printk messages and use alias_name() in them. Example: (current) printk("disk name is %s\n", disk->disk_name); (new) printk("disk name is %s\n", alias_name(disk)); Users can use alphabets, numbers, '-' and '_' in "alias" attribute. A disk can have an "alias" which length is up to 255 bytes. This attribute is write-once. Suggested-by: James Bottomley Suggested-by: Jon Masters Signed-off-by: Nao Nishijima Signed-off-by: James Bottomley

block: add GENHD_FL_NO_PART_SCAN

2011-08-23T18:01:04Z

There are cases where suppressing partition scan is useful - e.g. for lo devices and pseudo SATA devices which advertise to be a disk but get upset on partition scan (some port multiplier control devices show such behavior). This patch adds GENHD_FL_NO_PART_SCAN which suppresses partition scan regardless of the number of possible partitions. disk_partitionable() is renamed to disk_part_scan_enabled() as suppressing partition scan doesn't imply the device can't be partitioned using BLKPG_ADD/DEL_PARTITION calls from userland. show_partition() now directly tests disk_max_parts() to maintain backward-compatibility. -v2: Updated to make it clear that only partition scan is suppressed not partitioning itself as suggested by Kay Sievers. Signed-off-by: Tejun Heo Cc: Kay Sievers Signed-off-by: Jens Axboe

block/genhd.c: remove useless cast in diskstats_show()

2011-08-02T10:43:50Z

Remove the (unsigned long long) cast in diskstats_show() and adjusts the seq_printf() format string to 'unsigned long' diskstats_show() uses part_stat_read() to get the stats, which either accesses the specified field in the struct disk_stats directly (non SMP) or sums up the per CPU values in a variable of the same type as the field, so in any case the result will have the same type and range as the specified field which for all disk_stats entries is unsigned long Also, for unsigned long ranges the output of %lu should be identical to the one of %llu, so no change in the actual proc entry contents. Signed-off-by: Herbert Poetzl Cc: Jens Axboe Signed-off-by: Andrew Morton Signed-off-by: Jens Axboe