kernel/linux.git, branch v4.9.152

Linux 4.9.152

2019-01-23T07:10:57+00:00

nbd: Use set_blocksize() to set device blocksize

2019-01-23T07:10:57+00:00

commit c8a83a6b54d0ca078de036aafb3f6af58c1dc5eb upstream. NBD can update block device block size implicitely through bd_set_size(). Make it explicitely set blocksize with set_blocksize() as this behavior of bd_set_size() is going away. CC: Josef Bacik Signed-off-by: Jan Kara Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

nbd: set the logical and physical blocksize properly

2019-01-23T07:10:57+00:00

commit e544541b0765c341174613b416d4b074fa7571c2 upstream. We noticed when trying to do O_DIRECT to an export on the server side that we were getting requests smaller than the 4k sectorsize of the device. This is because the client isn't setting the logical and physical blocksizes properly for the underlying device. Fix this up by setting the queue blocksizes and then calling bd_set_size. Signed-off-by: Josef Bacik Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

media: vb2: be sure to unlock mutex on errors

2019-01-23T07:10:57+00:00

commit c06ef2e9acef4cda1feee2ce055b8086e33d251a upstream. As reported by smatch: drivers/media/common/videobuf2/videobuf2-core.c: drivers/media/common/videobuf2/videobuf2-core.c:2159 vb2_mmap() warn: inconsistent returns 'mutex:&q->mmap_lock'. Locked on: line 2148 Unlocked on: line 2100 line 2108 line 2113 line 2118 line 2156 line 2159 There is one error condition that doesn't unlock a mutex. Fixes: cd26d1c4d1bc ("media: vb2: vb2_mmap: move lock up") Reviewed-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Greg Kroah-Hartman

mm, memcg: fix reclaim deadlock with writeback

2019-01-23T07:10:57+00:00

commit 63f3655f950186752236bb88a22f8252c11ce394 upstream. Liu Bo has experienced a deadlock between memcg (legacy) reclaim and the ext4 writeback task1: wait_on_page_bit+0x82/0xa0 shrink_page_list+0x907/0x960 shrink_inactive_list+0x2c7/0x680 shrink_node_memcg+0x404/0x830 shrink_node+0xd8/0x300 do_try_to_free_pages+0x10d/0x330 try_to_free_mem_cgroup_pages+0xd5/0x1b0 try_charge+0x14d/0x720 memcg_kmem_charge_memcg+0x3c/0xa0 memcg_kmem_charge+0x7e/0xd0 __alloc_pages_nodemask+0x178/0x260 alloc_pages_current+0x95/0x140 pte_alloc_one+0x17/0x40 __pte_alloc+0x1e/0x110 alloc_set_pte+0x5fe/0xc20 do_fault+0x103/0x970 handle_mm_fault+0x61e/0xd10 __do_page_fault+0x252/0x4d0 do_page_fault+0x30/0x80 page_fault+0x28/0x30 task2: __lock_page+0x86/0xa0 mpage_prepare_extent_to_map+0x2e7/0x310 [ext4] ext4_writepages+0x479/0xd60 do_writepages+0x1e/0x30 __writeback_single_inode+0x45/0x320 writeback_sb_inodes+0x272/0x600 __writeback_inodes_wb+0x92/0xc0 wb_writeback+0x268/0x300 wb_workfn+0xb4/0x390 process_one_work+0x189/0x420 worker_thread+0x4e/0x4b0 kthread+0xe6/0x100 ret_from_fork+0x41/0x50 He adds "task1 is waiting for the PageWriteback bit of the page that task2 has collected in mpd->io_submit->io_bio, and tasks2 is waiting for the LOCKED bit the page which tasks1 has locked" More precisely task1 is handling a page fault and it has a page locked while it charges a new page table to a memcg. That in turn hits a memory limit reclaim and the memcg reclaim for legacy controller is waiting on the writeback but that is never going to finish because the writeback itself is waiting for the page locked in the #PF path. So this is essentially ABBA deadlock: lock_page(A) SetPageWriteback(A) unlock_page(A) lock_page(B) lock_page(B) pte_alloc_pne shrink_page_list wait_on_page_writeback(A) SetPageWriteback(B) unlock_page(B) # flush A, B to clear the writeback This accumulating of more pages to flush is used by several filesystems to generate a more optimal IO patterns. Waiting for the writeback in legacy memcg controller is a workaround for pre-mature OOM killer invocations because there is no dirty IO throttling available for the controller. There is no easy way around that unfortunately. Therefore fix this specific issue by pre-allocating the page table outside of the page lock. We have that handy infrastructure for that already so simply reuse the fault-around pattern which already does this. There are probably other hidden __GFP_ACCOUNT | GFP_KERNEL allocations from under a fs page locked but they should be really rare. I am not aware of a better solution unfortunately. [akpm@linux-foundation.org: fix mm/memory.c:__do_fault()] [akpm@linux-foundation.org: coding-style fixes] [mhocko@kernel.org: enhance comment, per Johannes] Link: http://lkml.kernel.org/r/20181214084948.GA5624@dhcp22.suse.cz Link: http://lkml.kernel.org/r/20181213092221.27270-1-mhocko@kernel.org Fixes: c3b94f44fcb0 ("memcg: further prevent OOM with too many dirty pages") Signed-off-by: Michal Hocko Reported-by: Liu Bo Debugged-by: Liu Bo Acked-by: Kirill A. Shutemov Acked-by: Johannes Weiner Reviewed-by: Liu Bo Cc: Jan Kara Cc: Dave Chinner Cc: Theodore Ts'o Cc: Vladimir Davydov Cc: Shakeel Butt Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

drm/fb-helper: Ignore the value of fb_var_screeninfo.pixclock

2019-01-23T07:10:57+00:00

commit 66a8d5bfb518f9f12d47e1d2dce1732279f9451e upstream. Strict requirement of pixclock to be zero breaks support of SDL 1.2 which contains hardcoded table of supported video modes with non-zero pixclock values[1]. To better understand which pixclock values are considered valid and how driver should handle these values, I briefly examined few existing fbdev drivers and documentation in Documentation/fb/. And it looks like there are no strict rules on that and actual behaviour varies: * some drivers treat (pixclock == 0) as "use defaults" (uvesafb.c); * some treat (pixclock == 0) as invalid value which leads to -EINVAL (clps711x-fb.c); * some pass converted pixclock value to hardware (uvesafb.c); * some are trying to find nearest value from predefined table (vga16fb.c, video_gx.c). Given this, I believe that it should be safe to just ignore this value if changing is not supported. It seems that any portable fbdev application which was not written only for one specific device working under one specific kernel version should not rely on any particular behaviour of pixclock anyway. However, while enabling SDL1 applications to work out of the box when there is no /etc/fb.modes with valid settings, this change affects the video mode choosing logic in SDL. Depending on current screen resolution, contents of /etc/fb.modes and resolution requested by application, this may lead to user-visible difference (not always): image will be displayed in a right way, but it will be aligned to the left instead of center. There is no "right behaviour" here as well, as emulated fbdev, opposing to old fbdev drivers, simply ignores any requsts of video mode changes with resolutions smaller than current. The easiest way to reproduce this problem is to install sdl-sopwith[2], remove /etc/fb.modes file if it exists, and then try to run sopwith from console without X. At least in Fedora 29, sopwith may be simply installed from standard repositories. [1] SDL 1.2.15 source code, src/video/fbcon/SDL_fbvideo.c, vesa_timings [2] http://sdl-sopwith.sourceforge.net/ Signed-off-by: Ivan Mironov Cc: stable@vger.kernel.org Fixes: 79e539453b34e ("DRM: i915: add mode setting support") Fixes: 771fe6b912fca ("drm/radeon: introduce kernel modesetting for radeon hardware") Fixes: 785b93ef8c309 ("drm/kms: move driver specific fb common code to helper functions (v2)") Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20190108072353.28078-3-mironov.ivan@gmail.com Signed-off-by: Greg Kroah-Hartman

loop: Fix double mutex_unlock(&loop_ctl_mutex) in loop_control_ioctl()

2019-01-23T07:10:57+00:00

commit 628bd85947091830a8c4872adfd5ed1d515a9cf2 upstream. Commit 0a42e99b58a20883 ("loop: Get rid of loop_index_mutex") forgot to remove mutex_unlock(&loop_ctl_mutex) from loop_control_ioctl() when replacing loop_index_mutex with loop_ctl_mutex. Fixes: 0a42e99b58a20883 ("loop: Get rid of loop_index_mutex") Reported-by: syzbot Reviewed-by: Ming Lei Reviewed-by: Jan Kara Signed-off-by: Tetsuo Handa Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

loop: Get rid of loop_index_mutex

2019-01-23T07:10:56+00:00

commit 0a42e99b58a208839626465af194cfe640ef9493 upstream. Now that loop_ctl_mutex is global, just get rid of loop_index_mutex as there is no good reason to keep these two separate and it just complicates the locking. Signed-off-by: Jan Kara Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

loop: Fold __loop_release into loop_release

2019-01-23T07:10:56+00:00

commit 967d1dc144b50ad005e5eecdfadfbcfb399ffff6 upstream. __loop_release() has a single call site. Fold it there. This is currently not a huge win but it will make following replacement of loop_index_mutex more obvious. Signed-off-by: Jan Kara Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

block/loop: Use global lock for ioctl() operation.

2019-01-23T07:10:56+00:00

commit 310ca162d779efee8a2dc3731439680f3e9c1e86 upstream. syzbot is reporting NULL pointer dereference [1] which is caused by race condition between ioctl(loop_fd, LOOP_CLR_FD, 0) versus ioctl(other_loop_fd, LOOP_SET_FD, loop_fd) due to traversing other loop devices at loop_validate_file() without holding corresponding lo->lo_ctl_mutex locks. Since ioctl() request on loop devices is not frequent operation, we don't need fine grained locking. Let's use global lock in order to allow safe traversal at loop_validate_file(). Note that syzbot is also reporting circular locking dependency between bdev->bd_mutex and lo->lo_ctl_mutex [2] which is caused by calling blkdev_reread_part() with lock held. This patch does not address it. [1] https://syzkaller.appspot.com/bug?id=f3cfe26e785d85f9ee259f385515291d21bd80a3 [2] https://syzkaller.appspot.com/bug?id=bf154052f0eea4bc7712499e4569505907d15889 Signed-off-by: Tetsuo Handa Reported-by: syzbot Reviewed-by: Jan Kara Signed-off-by: Jan Kara Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman