linux.git/block, branch v4.1.29 Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git block: fix use-after-free in sys_ioprio_get() 2016-07-19T17:57:58+00:00 Omar Sandoval osandov@fb.com 2016-07-01T07:39:35+00:00 23c63b8c08fe3f0b21594ee1ac4de0fa52225f79 [ Upstream commit 8ba8682107ee2ca3347354e018865d8e1967c5f4 ] get_task_ioprio() accesses the task->io_context without holding the task lock and thus can race with exit_io_context(), leading to a use-after-free. The reproducer below hits this within a few seconds on my 4-core QEMU VM: #define _GNU_SOURCE #include <assert.h> #include <unistd.h> #include <sys/syscall.h> #include <sys/wait.h> int main(int argc, char **argv) { pid_t pid, child; long nproc, i; /* ioprio_set(IOPRIO_WHO_PROCESS, 0, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0)); */ syscall(SYS_ioprio_set, 1, 0, 0x6000); nproc = sysconf(_SC_NPROCESSORS_ONLN); for (i = 0; i < nproc; i++) { pid = fork(); assert(pid != -1); if (pid == 0) { for (;;) { pid = fork(); assert(pid != -1); if (pid == 0) { _exit(0); } else { child = wait(NULL); assert(child == pid); } } } pid = fork(); assert(pid != -1); if (pid == 0) { for (;;) { /* ioprio_get(IOPRIO_WHO_PGRP, 0); */ syscall(SYS_ioprio_get, 2, 0); } } } for (;;) { /* ioprio_get(IOPRIO_WHO_PGRP, 0); */ syscall(SYS_ioprio_get, 2, 0); } return 0; } This gets us KASAN dumps like this: [ 35.526914] ================================================================== [ 35.530009] BUG: KASAN: out-of-bounds in get_task_ioprio+0x7b/0x90 at addr ffff880066f34e6c [ 35.530009] Read of size 2 by task ioprio-gpf/363 [ 35.530009] ============================================================================= [ 35.530009] BUG blkdev_ioc (Not tainted): kasan: bad access detected [ 35.530009] ----------------------------------------------------------------------------- [ 35.530009] Disabling lock debugging due to kernel taint [ 35.530009] INFO: Allocated in create_task_io_context+0x2b/0x370 age=0 cpu=0 pid=360 [ 35.530009] ___slab_alloc+0x55d/0x5a0 [ 35.530009] __slab_alloc.isra.20+0x2b/0x40 [ 35.530009] kmem_cache_alloc_node+0x84/0x200 [ 35.530009] create_task_io_context+0x2b/0x370 [ 35.530009] get_task_io_context+0x92/0xb0 [ 35.530009] copy_process.part.8+0x5029/0x5660 [ 35.530009] _do_fork+0x155/0x7e0 [ 35.530009] SyS_clone+0x19/0x20 [ 35.530009] do_syscall_64+0x195/0x3a0 [ 35.530009] return_from_SYSCALL_64+0x0/0x6a [ 35.530009] INFO: Freed in put_io_context+0xe7/0x120 age=0 cpu=0 pid=1060 [ 35.530009] __slab_free+0x27b/0x3d0 [ 35.530009] kmem_cache_free+0x1fb/0x220 [ 35.530009] put_io_context+0xe7/0x120 [ 35.530009] put_io_context_active+0x238/0x380 [ 35.530009] exit_io_context+0x66/0x80 [ 35.530009] do_exit+0x158e/0x2b90 [ 35.530009] do_group_exit+0xe5/0x2b0 [ 35.530009] SyS_exit_group+0x1d/0x20 [ 35.530009] entry_SYSCALL_64_fastpath+0x1a/0xa4 [ 35.530009] INFO: Slab 0xffffea00019bcd00 objects=20 used=4 fp=0xffff880066f34ff0 flags=0x1fffe0000004080 [ 35.530009] INFO: Object 0xffff880066f34e58 @offset=3672 fp=0x0000000000000001 [ 35.530009] ================================================================== Fix it by grabbing the task lock while we poke at the io_context. Cc: stable@vger.kernel.org Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> 
[ Upstream commit 8ba8682107ee2ca3347354e018865d8e1967c5f4 ]

get_task_ioprio() accesses the task->io_context without holding the task
lock and thus can race with exit_io_context(), leading to a
use-after-free. The reproducer below hits this within a few seconds on
my 4-core QEMU VM:

#define _GNU_SOURCE
#include <assert.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/wait.h>

int main(int argc, char **argv)
{
	pid_t pid, child;
	long nproc, i;

	/* ioprio_set(IOPRIO_WHO_PROCESS, 0, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0)); */
	syscall(SYS_ioprio_set, 1, 0, 0x6000);

	nproc = sysconf(_SC_NPROCESSORS_ONLN);

	for (i = 0; i < nproc; i++) {
		pid = fork();
		assert(pid != -1);
		if (pid == 0) {
			for (;;) {
				pid = fork();
				assert(pid != -1);
				if (pid == 0) {
					_exit(0);
				} else {
					child = wait(NULL);
					assert(child == pid);
				}
			}
		}

		pid = fork();
		assert(pid != -1);
		if (pid == 0) {
			for (;;) {
				/* ioprio_get(IOPRIO_WHO_PGRP, 0); */
				syscall(SYS_ioprio_get, 2, 0);
			}
		}
	}

	for (;;) {
		/* ioprio_get(IOPRIO_WHO_PGRP, 0); */
		syscall(SYS_ioprio_get, 2, 0);
	}

	return 0;
}

This gets us KASAN dumps like this:

[   35.526914] ==================================================================
[   35.530009] BUG: KASAN: out-of-bounds in get_task_ioprio+0x7b/0x90 at addr ffff880066f34e6c
[   35.530009] Read of size 2 by task ioprio-gpf/363
[   35.530009] =============================================================================
[   35.530009] BUG blkdev_ioc (Not tainted): kasan: bad access detected
[   35.530009] -----------------------------------------------------------------------------

[   35.530009] Disabling lock debugging due to kernel taint
[   35.530009] INFO: Allocated in create_task_io_context+0x2b/0x370 age=0 cpu=0 pid=360
[   35.530009] 	___slab_alloc+0x55d/0x5a0
[   35.530009] 	__slab_alloc.isra.20+0x2b/0x40
[   35.530009] 	kmem_cache_alloc_node+0x84/0x200
[   35.530009] 	create_task_io_context+0x2b/0x370
[   35.530009] 	get_task_io_context+0x92/0xb0
[   35.530009] 	copy_process.part.8+0x5029/0x5660
[   35.530009] 	_do_fork+0x155/0x7e0
[   35.530009] 	SyS_clone+0x19/0x20
[   35.530009] 	do_syscall_64+0x195/0x3a0
[   35.530009] 	return_from_SYSCALL_64+0x0/0x6a
[   35.530009] INFO: Freed in put_io_context+0xe7/0x120 age=0 cpu=0 pid=1060
[   35.530009] 	__slab_free+0x27b/0x3d0
[   35.530009] 	kmem_cache_free+0x1fb/0x220
[   35.530009] 	put_io_context+0xe7/0x120
[   35.530009] 	put_io_context_active+0x238/0x380
[   35.530009] 	exit_io_context+0x66/0x80
[   35.530009] 	do_exit+0x158e/0x2b90
[   35.530009] 	do_group_exit+0xe5/0x2b0
[   35.530009] 	SyS_exit_group+0x1d/0x20
[   35.530009] 	entry_SYSCALL_64_fastpath+0x1a/0xa4
[   35.530009] INFO: Slab 0xffffea00019bcd00 objects=20 used=4 fp=0xffff880066f34ff0 flags=0x1fffe0000004080
[   35.530009] INFO: Object 0xffff880066f34e58 @offset=3672 fp=0x0000000000000001
[   35.530009] ==================================================================

Fix it by grabbing the task lock while we poke at the io_context.

Cc: stable@vger.kernel.org
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
dm: fix excessive dm-mq context switching 2016-04-18T12:50:38+00:00 Mike Snitzer snitzer@redhat.com 2016-02-05T13:49:01+00:00 fb1840e257d26b6aad69b864cb7ed4a67ab986b6 [ Upstream commit 6acfe68bac7e6f16dc312157b1fa6e2368985013 ] Request-based DM's blk-mq support (dm-mq) was reported to be 50% slower than if an underlying null_blk device were used directly. One of the reasons for this drop in performance is that blk_insert_clone_request() was calling blk_mq_insert_request() with @async=true. This forced the use of kblockd_schedule_delayed_work_on() to run the blk-mq hw queues which ushered in ping-ponging between process context (fio in this case) and kblockd's kworker to submit the cloned request. The ftrace function_graph tracer showed: kworker-2013 => fio-12190 fio-12190 => kworker-2013 ... kworker-2013 => fio-12190 fio-12190 => kworker-2013 ... Fixing blk_insert_clone_request()'s blk_mq_insert_request() call to _not_ use kblockd to submit the cloned requests isn't enough to eliminate the observed context switches. In addition to this dm-mq specific blk-core fix, there are 2 DM core fixes to dm-mq that (when paired with the blk-core fix) completely eliminate the observed context switching: 1) don't blk_mq_run_hw_queues in blk-mq request completion Motivated by desire to reduce overhead of dm-mq, punting to kblockd just increases context switches. In my testing against a really fast null_blk device there was no benefit to running blk_mq_run_hw_queues() on completion (and no other blk-mq driver does this). So hopefully this change doesn't induce the need for yet another revert like commit 621739b00e16ca2d ! 2) use blk_mq_complete_request() in dm_complete_request() blk_complete_request() doesn't offer the traditional q->mq_ops vs .request_fn branching pattern that other historic block interfaces do (e.g. blk_get_request). Using blk_mq_complete_request() for blk-mq requests is important for performance. It should be noted that, like blk_complete_request(), blk_mq_complete_request() doesn't natively handle partial completions -- but the request-based DM-multipath target does provide the required partial completion support by dm.c:end_clone_bio() triggering requeueing of the request via dm-mpath.c:multipath_end_io()'s return of DM_ENDIO_REQUEUE. dm-mq fix #2 is _much_ more important than #1 for eliminating the context switches. Before: cpu : usr=15.10%, sys=59.39%, ctx=7905181, majf=0, minf=475 After: cpu : usr=20.60%, sys=79.35%, ctx=2008, majf=0, minf=472 With these changes multithreaded async read IOPs improved from ~950K to ~1350K for this dm-mq stacked on null_blk test-case. The raw read IOPs of the underlying null_blk device for the same workload is ~1950K. Fixes: 7fb4898e0 ("block: add blk-mq support to blk_insert_cloned_request()") Fixes: bfebd1cdb ("dm: add full blk-mq support to request-based DM") Cc: stable@vger.kernel.org # 4.1+ Reported-by: Sagi Grimberg <sagig@dev.mellanox.co.il> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> 
[ Upstream commit 6acfe68bac7e6f16dc312157b1fa6e2368985013 ]

Request-based DM's blk-mq support (dm-mq) was reported to be 50% slower
than if an underlying null_blk device were used directly.  One of the
reasons for this drop in performance is that blk_insert_clone_request()
was calling blk_mq_insert_request() with @async=true.  This forced the
use of kblockd_schedule_delayed_work_on() to run the blk-mq hw queues
which ushered in ping-ponging between process context (fio in this case)
and kblockd's kworker to submit the cloned request.  The ftrace
function_graph tracer showed:

  kworker-2013  =>   fio-12190
  fio-12190    =>  kworker-2013
  ...
  kworker-2013  =>   fio-12190
  fio-12190    =>  kworker-2013
  ...

Fixing blk_insert_clone_request()'s blk_mq_insert_request() call to
_not_ use kblockd to submit the cloned requests isn't enough to
eliminate the observed context switches.

In addition to this dm-mq specific blk-core fix, there are 2 DM core
fixes to dm-mq that (when paired with the blk-core fix) completely
eliminate the observed context switching:

1)  don't blk_mq_run_hw_queues in blk-mq request completion

    Motivated by desire to reduce overhead of dm-mq, punting to kblockd
    just increases context switches.

    In my testing against a really fast null_blk device there was no benefit
    to running blk_mq_run_hw_queues() on completion (and no other blk-mq
    driver does this).  So hopefully this change doesn't induce the need for
    yet another revert like commit 621739b00e16ca2d !

2)  use blk_mq_complete_request() in dm_complete_request()

    blk_complete_request() doesn't offer the traditional q->mq_ops vs
    .request_fn branching pattern that other historic block interfaces
    do (e.g. blk_get_request).  Using blk_mq_complete_request() for
    blk-mq requests is important for performance.  It should be noted
    that, like blk_complete_request(), blk_mq_complete_request() doesn't
    natively handle partial completions -- but the request-based
    DM-multipath target does provide the required partial completion
    support by dm.c:end_clone_bio() triggering requeueing of the request
    via dm-mpath.c:multipath_end_io()'s return of DM_ENDIO_REQUEUE.

dm-mq fix #2 is _much_ more important than #1 for eliminating the
context switches.
Before: cpu          : usr=15.10%, sys=59.39%, ctx=7905181, majf=0, minf=475
After:  cpu          : usr=20.60%, sys=79.35%, ctx=2008, majf=0, minf=472

With these changes multithreaded async read IOPs improved from ~950K
to ~1350K for this dm-mq stacked on null_blk test-case.  The raw read
IOPs of the underlying null_blk device for the same workload is ~1950K.

Fixes: 7fb4898e0 ("block: add blk-mq support to blk_insert_cloned_request()")
Fixes: bfebd1cdb ("dm: add full blk-mq support to request-based DM")
Cc: stable@vger.kernel.org # 4.1+
Reported-by: Sagi Grimberg <sagig@dev.mellanox.co.il>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
bio: return EINTR if copying to user space got interrupted 2016-03-04T15:25:43+00:00 Hannes Reinecke hare@suse.de 2016-02-12T08:39:15+00:00 f3dd341b9230ac943f317efa4c5b1bfae587434b [ Upstream commit 2d99b55d378c996b9692a0c93dd25f4ed5d58934 ] Commit 35dc248383bbab0a7203fca4d722875bc81ef091 introduced a check for current->mm to see if we have a user space context and only copies data if we do. Now if an IO gets interrupted by a signal data isn't copied into user space any more (as we don't have a user space context) but user space isn't notified about it. This patch modifies the behaviour to return -EINTR from bio_uncopy_user() to notify userland that a signal has interrupted the syscall, otherwise it could lead to a situation where the caller may get a buffer with no data returned. This can be reproduced by issuing SG_IO ioctl()s in one thread while constantly sending signals to it. Fixes: 35dc248 [SCSI] sg: Fix user memory corruption when SG_IO is interrupted by a signal Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Hannes Reinecke <hare@suse.de> Cc: stable@vger.kernel.org # v.3.11+ Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> 
[ Upstream commit 2d99b55d378c996b9692a0c93dd25f4ed5d58934 ]

Commit 35dc248383bbab0a7203fca4d722875bc81ef091 introduced a check for
current->mm to see if we have a user space context and only copies data
if we do. Now if an IO gets interrupted by a signal data isn't copied
into user space any more (as we don't have a user space context) but
user space isn't notified about it.

This patch modifies the behaviour to return -EINTR from bio_uncopy_user()
to notify userland that a signal has interrupted the syscall, otherwise
it could lead to a situation where the caller may get a buffer with
no data returned.

This can be reproduced by issuing SG_IO ioctl()s in one thread while
constantly sending signals to it.

Fixes: 35dc248 [SCSI] sg: Fix user memory corruption when SG_IO is interrupted by a signal
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Cc: stable@vger.kernel.org # v.3.11+
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
blk-mq: fix buffer overflow when reading sysfs file of 'pending' 2015-09-29T17:25:56+00:00 Ming Lei ming.lei@canonical.com 2015-08-09T07:41:50+00:00 1af97771b397a9ca2ee984c3277bcada3eec95cd commit 596f5aad2a704b72934e5abec1b1b4114c16f45b upstream. There may be lots of pending requests so that the buffer of PAGE_SIZE can't hold them at all. One typical example is scsi-mq, the queue depth(.can_queue) of scsi_host and blk-mq is quite big but scsi_device's queue_depth is a bit small(.cmd_per_lun), then it is quite easy to have lots of pending requests in hw queue. This patch fixes the following warning and the related memory destruction. [ 359.025101] fill_read_buffer: blk_mq_hw_sysfs_show+0x0/0x7d returned bad count^M [ 359.055595] irq event stamp: 15537^M [ 359.055606] general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC ^M [ 359.055614] Dumping ftrace buffer:^M [ 359.055660] (ftrace buffer empty)^M [ 359.055672] Modules linked in: nbd ipv6 kvm_intel kvm serio_raw^M [ 359.055678] CPU: 4 PID: 21631 Comm: stress-ng-sysfs Not tainted 4.2.0-rc5-next-20150805 #434^M [ 359.055679] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011^M [ 359.055682] task: ffff8802161cc000 ti: ffff88021b4a8000 task.ti: ffff88021b4a8000^M [ 359.055693] RIP: 0010:[<ffffffff811541c5>] [<ffffffff811541c5>] __kmalloc+0xe8/0x152^M Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 596f5aad2a704b72934e5abec1b1b4114c16f45b upstream.

There may be lots of pending requests so that the buffer of PAGE_SIZE
can't hold them at all.

One typical example is scsi-mq, the queue depth(.can_queue) of
scsi_host and blk-mq is quite big but scsi_device's queue_depth
is a bit small(.cmd_per_lun), then it is quite easy to have lots
of pending requests in hw queue.

This patch fixes the following warning and the related memory
destruction.

[  359.025101] fill_read_buffer: blk_mq_hw_sysfs_show+0x0/0x7d returned bad count^M
[  359.055595] irq event stamp: 15537^M
[  359.055606] general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC ^M
[  359.055614] Dumping ftrace buffer:^M
[  359.055660]    (ftrace buffer empty)^M
[  359.055672] Modules linked in: nbd ipv6 kvm_intel kvm serio_raw^M
[  359.055678] CPU: 4 PID: 21631 Comm: stress-ng-sysfs Not tainted 4.2.0-rc5-next-20150805 #434^M
[  359.055679] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011^M
[  359.055682] task: ffff8802161cc000 ti: ffff88021b4a8000 task.ti: ffff88021b4a8000^M
[  359.055693] RIP: 0010:[<ffffffff811541c5>]  [<ffffffff811541c5>] __kmalloc+0xe8/0x152^M

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sd: Fix maximum I/O size for BLOCK_PC requests 2015-09-13T16:07:45+00:00 Martin K. Petersen martin.petersen@oracle.com 2015-06-23T16:13:59+00:00 2a51c43d1d6824c3fce1511e0f30db51274e7cd7 commit 4f258a46346c03fa0bbb6199ffaf4e1f9f599660 upstream. Commit bcdb247c6b6a ("sd: Limit transfer length") clamped the maximum size of an I/O request to the MAXIMUM TRANSFER LENGTH field in the BLOCK LIMITS VPD. This had the unfortunate effect of also limiting the maximum size of non-filesystem requests sent to the device through sg/bsg. Avoid using blk_queue_max_hw_sectors() and set the max_sectors queue limit directly. Also update the comment in blk_limits_max_hw_sectors() to clarify that max_hw_sectors defines the limit for the I/O controller only. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Reported-by: Brian King <brking@linux.vnet.ibm.com> Tested-by: Brian King <brking@linux.vnet.ibm.com> Signed-off-by: James Bottomley <JBottomley@Odin.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 4f258a46346c03fa0bbb6199ffaf4e1f9f599660 upstream.

Commit bcdb247c6b6a ("sd: Limit transfer length") clamped the maximum
size of an I/O request to the MAXIMUM TRANSFER LENGTH field in the BLOCK
LIMITS VPD. This had the unfortunate effect of also limiting the maximum
size of non-filesystem requests sent to the device through sg/bsg.

Avoid using blk_queue_max_hw_sectors() and set the max_sectors queue
limit directly.

Also update the comment in blk_limits_max_hw_sectors() to clarify that
max_hw_sectors defines the limit for the I/O controller only.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reported-by: Brian King <brking@linux.vnet.ibm.com>
Tested-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
blk-mq: set default timeout as 30 seconds 2015-08-10T19:21:57+00:00 Ming Lei ming.lei@canonical.com 2015-07-16T11:53:22+00:00 3425ebac158abf137ce7dcbe062baeb4c04e0097 commit e56f698bd0720e17f10f39e8b0b5b446ad0ab22c upstream. It is reasonable to set default timeout of request as 30 seconds instead of 30000 ticks, which may be 300 seconds if HZ is 100, for example, some arm64 based systems may choose 100 HZ. Signed-off-by: Ming Lei <ming.lei@canonical.com> Fixes: c76cbbcf4044 ("blk-mq: put blk_queue_rq_timeout together in blk_mq_init_queue()" Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit e56f698bd0720e17f10f39e8b0b5b446ad0ab22c upstream.

It is reasonable to set default timeout of request as 30 seconds instead of
30000 ticks, which may be 300 seconds if HZ is 100, for example, some arm64
based systems may choose 100 HZ.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Fixes: c76cbbcf4044 ("blk-mq: put blk_queue_rq_timeout together in blk_mq_init_queue()"
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
blkcg: fix gendisk reference leak in blkg_conf_prep() 2015-08-10T19:21:56+00:00 Tejun Heo tj@kernel.org 2015-07-22T22:05:53+00:00 1fbb15f220a6740327764b3775566771a4746fe6 commit 5f6c2d2b7dbb541c1e922538c49fa04c494ae3d7 upstream. When a blkcg configuration is targeted to a partition rather than a whole device, blkg_conf_prep fails with -EINVAL; unfortunately, it forgets to put the gendisk ref in that case. Fix it. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 5f6c2d2b7dbb541c1e922538c49fa04c494ae3d7 upstream.

When a blkcg configuration is targeted to a partition rather than a
whole device, blkg_conf_prep fails with -EINVAL; unfortunately, it
forgets to put the gendisk ref in that case.  Fix it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
bio integrity: do not assume bio_integrity_pool exists if bioset exists 2015-08-10T19:21:52+00:00 Mike Snitzer snitzer@redhat.com 2015-07-01T16:57:40+00:00 62a3fb2346044a21c8dc4d43a7812e7a54adb39b commit bb8bd38b9a1685334b73e8c62e128cbedb875867 upstream. bio_integrity_alloc() and bio_integrity_free() assume that if a bio was allocated from a bioset that that bioset also had its bio_integrity_pool allocated using bioset_integrity_create(). This is a very bad assumption given that bioset_create() and bioset_integrity_create() are completely disjoint. Not all callers of bioset_create() have been trained to also call bioset_integrity_create() -- and they may not care to be. Fix this by falling back to kmalloc'ing 'struct bio_integrity_payload' rather than force all bioset consumers to (wastefully) preallocate a bio_integrity_pool that they very likely won't actually need (given the niche nature of the current block integrity support). Otherwise, a NULL pointer "Kernel BUG" with a trace like the following will be observed (as seen on s390x using zfcp storage) because dm-io doesn't use bioset_integrity_create() when creating its bioset: [ 791.643338] Call Trace: [ 791.643339] ([<00000003df98b848>] 0x3df98b848) [ 791.643341] [<00000000002c5de8>] bio_integrity_alloc+0x48/0xf8 [ 791.643348] [<00000000002c6486>] bio_integrity_prep+0xae/0x2f0 [ 791.643349] [<0000000000371e38>] blk_queue_bio+0x1c8/0x3d8 [ 791.643355] [<000000000036f8d0>] generic_make_request+0xc0/0x100 [ 791.643357] [<000000000036f9b2>] submit_bio+0xa2/0x198 [ 791.643406] [<000003ff801f9774>] dispatch_io+0x15c/0x3b0 [dm_mod] [ 791.643419] [<000003ff801f9b3e>] dm_io+0x176/0x2f0 [dm_mod] [ 791.643423] [<000003ff8074b28a>] do_reads+0x13a/0x1a8 [dm_mirror] [ 791.643425] [<000003ff8074b43a>] do_mirror+0x142/0x298 [dm_mirror] [ 791.643428] [<0000000000154fca>] process_one_work+0x18a/0x3f8 [ 791.643432] [<000000000015598a>] worker_thread+0x132/0x3b0 [ 791.643435] [<000000000015d49a>] kthread+0xd2/0xd8 [ 791.643438] [<00000000005bc0ca>] kernel_thread_starter+0x6/0xc [ 791.643446] [<00000000005bc0c4>] kernel_thread_starter+0x0/0xc Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit bb8bd38b9a1685334b73e8c62e128cbedb875867 upstream.

bio_integrity_alloc() and bio_integrity_free() assume that if a bio was
allocated from a bioset that that bioset also had its bio_integrity_pool
allocated using bioset_integrity_create().  This is a very bad
assumption given that bioset_create() and bioset_integrity_create() are
completely disjoint.  Not all callers of bioset_create() have been
trained to also call bioset_integrity_create() -- and they may not care
to be.

Fix this by falling back to kmalloc'ing 'struct bio_integrity_payload'
rather than force all bioset consumers to (wastefully) preallocate a
bio_integrity_pool that they very likely won't actually need (given the
niche nature of the current block integrity support).

Otherwise, a NULL pointer "Kernel BUG" with a trace like the following
will be observed (as seen on s390x using zfcp storage) because dm-io
doesn't use bioset_integrity_create() when creating its bioset:

    [  791.643338] Call Trace:
    [  791.643339] ([<00000003df98b848>] 0x3df98b848)
    [  791.643341]  [<00000000002c5de8>] bio_integrity_alloc+0x48/0xf8
    [  791.643348]  [<00000000002c6486>] bio_integrity_prep+0xae/0x2f0
    [  791.643349]  [<0000000000371e38>] blk_queue_bio+0x1c8/0x3d8
    [  791.643355]  [<000000000036f8d0>] generic_make_request+0xc0/0x100
    [  791.643357]  [<000000000036f9b2>] submit_bio+0xa2/0x198
    [  791.643406]  [<000003ff801f9774>] dispatch_io+0x15c/0x3b0 [dm_mod]
    [  791.643419]  [<000003ff801f9b3e>] dm_io+0x176/0x2f0 [dm_mod]
    [  791.643423]  [<000003ff8074b28a>] do_reads+0x13a/0x1a8 [dm_mirror]
    [  791.643425]  [<000003ff8074b43a>] do_mirror+0x142/0x298 [dm_mirror]
    [  791.643428]  [<0000000000154fca>] process_one_work+0x18a/0x3f8
    [  791.643432]  [<000000000015598a>] worker_thread+0x132/0x3b0
    [  791.643435]  [<000000000015d49a>] kthread+0xd2/0xd8
    [  791.643438]  [<00000000005bc0ca>] kernel_thread_starter+0x6/0xc
    [  791.643446]  [<00000000005bc0c4>] kernel_thread_starter+0x0/0xc

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
block: Do a full clone when splitting discard bios 2015-08-03T16:29:07+00:00 Martin K. Petersen martin.petersen@oracle.com 2015-07-22T11:57:12+00:00 f7639d364c02eff91f433aca4e2d9ddaf37fb099 commit f3f5da624e0a891c34d8cd513c57f1d9b0c7dadc upstream. This fixes a data corruption bug when using discard on top of MD linear, raid0 and raid10 personalities. Commit 20d0189b1012 "block: Introduce new bio_split()" permits sharing the bio_vec between the two resulting bios. That is fine for read/write requests where the bio_vec is immutable. For discards, however, we need to be able to attach a payload and update the bio_vec so the page can get mapped to a scatterlist entry. Therefore the bio_vec can not be shared when splitting discards and we must do a full clone. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Reported-by: Seunguk Shin <seunguk.shin@samsung.com> Tested-by: Seunguk Shin <seunguk.shin@samsung.com> Cc: Seunguk Shin <seunguk.shin@samsung.com> Cc: Jens Axboe <axboe@fb.com> Cc: Kent Overstreet <kent.overstreet@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit f3f5da624e0a891c34d8cd513c57f1d9b0c7dadc upstream.

This fixes a data corruption bug when using discard on top of MD linear,
raid0 and raid10 personalities.

Commit 20d0189b1012 "block: Introduce new bio_split()" permits sharing
the bio_vec between the two resulting bios. That is fine for read/write
requests where the bio_vec is immutable. For discards, however, we need
to be able to attach a payload and update the bio_vec so the page can
get mapped to a scatterlist entry. Therefore the bio_vec can not be
shared when splitting discards and we must do a full clone.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reported-by: Seunguk Shin <seunguk.shin@samsung.com>
Tested-by: Seunguk Shin <seunguk.shin@samsung.com>
Cc: Seunguk Shin <seunguk.shin@samsung.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
block: fix ext_dev_lock lockdep report 2015-06-11T15:01:40+00:00 Dan Williams dan.j.williams@intel.com 2015-06-11T03:47:14+00:00 4d66e5e9b6d720d8463e11d027bd4ad91c8b1318 ================================= [ INFO: inconsistent lock state ] 4.1.0-rc7+ #217 Tainted: G O --------------------------------- inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. swapper/6/0 [HC0[0]:SC1[1]:HE1:SE0] takes: (ext_devt_lock){+.?...}, at: [<ffffffff8143a60c>] blk_free_devt+0x3c/0x70 {SOFTIRQ-ON-W} state was registered at: [<ffffffff810bf6b1>] __lock_acquire+0x461/0x1e70 [<ffffffff810c1947>] lock_acquire+0xb7/0x290 [<ffffffff818ac3a8>] _raw_spin_lock+0x38/0x50 [<ffffffff8143a07d>] blk_alloc_devt+0x6d/0xd0 <-- take the lock in process context [..] [<ffffffff810bf64e>] __lock_acquire+0x3fe/0x1e70 [<ffffffff810c00ad>] ? __lock_acquire+0xe5d/0x1e70 [<ffffffff810c1947>] lock_acquire+0xb7/0x290 [<ffffffff8143a60c>] ? blk_free_devt+0x3c/0x70 [<ffffffff818ac3a8>] _raw_spin_lock+0x38/0x50 [<ffffffff8143a60c>] ? blk_free_devt+0x3c/0x70 [<ffffffff8143a60c>] blk_free_devt+0x3c/0x70 <-- take the lock in softirq [<ffffffff8143bfec>] part_release+0x1c/0x50 [<ffffffff8158edf6>] device_release+0x36/0xb0 [<ffffffff8145ac2b>] kobject_cleanup+0x7b/0x1a0 [<ffffffff8145aad0>] kobject_put+0x30/0x70 [<ffffffff8158f147>] put_device+0x17/0x20 [<ffffffff8143c29c>] delete_partition_rcu_cb+0x16c/0x180 [<ffffffff8143c130>] ? read_dev_sector+0xa0/0xa0 [<ffffffff810e0e0f>] rcu_process_callbacks+0x2ff/0xa90 [<ffffffff810e0dcf>] ? rcu_process_callbacks+0x2bf/0xa90 [<ffffffff81067e2e>] __do_softirq+0xde/0x600 Neil sees this in his tests and it also triggers on pmem driver unbind for the libnvdimm tests. This fix is on top of an initial fix by Keith for incorrect usage of mutex_lock() in this path: 2da78092dda1 "block: Fix dev_t minor allocation lifetime". Both this and 2da78092dda1 are candidates for -stable. Fixes: 2da78092dda1 ("block: Fix dev_t minor allocation lifetime") Cc: <stable@vger.kernel.org> Cc: Keith Busch <keith.busch@intel.com> Reported-by: NeilBrown <neilb@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jens Axboe <axboe@fb.com> 
 =================================
 [ INFO: inconsistent lock state ]
 4.1.0-rc7+ #217 Tainted: G           O
 ---------------------------------
 inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
 swapper/6/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
  (ext_devt_lock){+.?...}, at: [<ffffffff8143a60c>] blk_free_devt+0x3c/0x70
 {SOFTIRQ-ON-W} state was registered at:
   [<ffffffff810bf6b1>] __lock_acquire+0x461/0x1e70
   [<ffffffff810c1947>] lock_acquire+0xb7/0x290
   [<ffffffff818ac3a8>] _raw_spin_lock+0x38/0x50
   [<ffffffff8143a07d>] blk_alloc_devt+0x6d/0xd0  <-- take the lock in process context
[..]
  [<ffffffff810bf64e>] __lock_acquire+0x3fe/0x1e70
  [<ffffffff810c00ad>] ? __lock_acquire+0xe5d/0x1e70
  [<ffffffff810c1947>] lock_acquire+0xb7/0x290
  [<ffffffff8143a60c>] ? blk_free_devt+0x3c/0x70
  [<ffffffff818ac3a8>] _raw_spin_lock+0x38/0x50
  [<ffffffff8143a60c>] ? blk_free_devt+0x3c/0x70
  [<ffffffff8143a60c>] blk_free_devt+0x3c/0x70    <-- take the lock in softirq
  [<ffffffff8143bfec>] part_release+0x1c/0x50
  [<ffffffff8158edf6>] device_release+0x36/0xb0
  [<ffffffff8145ac2b>] kobject_cleanup+0x7b/0x1a0
  [<ffffffff8145aad0>] kobject_put+0x30/0x70
  [<ffffffff8158f147>] put_device+0x17/0x20
  [<ffffffff8143c29c>] delete_partition_rcu_cb+0x16c/0x180
  [<ffffffff8143c130>] ? read_dev_sector+0xa0/0xa0
  [<ffffffff810e0e0f>] rcu_process_callbacks+0x2ff/0xa90
  [<ffffffff810e0dcf>] ? rcu_process_callbacks+0x2bf/0xa90
  [<ffffffff81067e2e>] __do_softirq+0xde/0x600

Neil sees this in his tests and it also triggers on pmem driver unbind
for the libnvdimm tests.  This fix is on top of an initial fix by Keith
for incorrect usage of mutex_lock() in this path: 2da78092dda1 "block:
Fix dev_t minor allocation lifetime".  Both this and 2da78092dda1 are
candidates for -stable.

Fixes: 2da78092dda1 ("block: Fix dev_t minor allocation lifetime")
Cc: <stable@vger.kernel.org>
Cc: Keith Busch <keith.busch@intel.com>
Reported-by: NeilBrown <neilb@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>