user/sven/linux.git, branch v4.14.94

Linux 4.14.94

2019-01-16T21:07:13Z

KVM: arm/arm64: Fix VMID alloc race by reverting to lock-less

2019-01-16T21:07:13Z

commit fb544d1ca65a89f7a3895f7531221ceeed74ada7 upstream. We recently addressed a VMID generation race by introducing a read/write lock around accesses and updates to the vmid generation values. However, kvm_arch_vcpu_ioctl_run() also calls need_new_vmid_gen() but does so without taking the read lock. As far as I can tell, this can lead to the same kind of race: VM 0, VCPU 0 VM 0, VCPU 1 ------------ ------------ update_vttbr (vmid 254) update_vttbr (vmid 1) // roll over read_lock(kvm_vmid_lock); force_vm_exit() local_irq_disable need_new_vmid_gen == false //because vmid gen matches enter_guest (vmid 254) kvm_arch.vttbr = : read_unlock(kvm_vmid_lock); enter_guest (vmid 1) Which results in running two VCPUs in the same VM with different VMIDs and (even worse) other VCPUs from other VMs could now allocate clashing VMID 254 from the new generation as long as VCPU 0 is not exiting. Attempt to solve this by making sure vttbr is updated before another CPU can observe the updated VMID generation. Cc: stable@vger.kernel.org Fixes: f0cf47d939d0 "KVM: arm/arm64: Close VMID generation race" Reviewed-by: Julien Thierry Signed-off-by: Christoffer Dall Signed-off-by: Marc Zyngier Signed-off-by: Greg Kroah-Hartman

sunrpc: use-after-free in svc_process_common()

2019-01-16T21:07:13Z

commit d4b09acf924b84bae77cad090a9d108e70b43643 upstream. if node have NFSv41+ mounts inside several net namespaces it can lead to use-after-free in svc_process_common() svc_process_common() /* Setup reply header */ rqstp->rq_xprt->xpt_ops->xpo_prep_reply_hdr(rqstp); <<< HERE svc_process_common() can use incorrect rqstp->rq_xprt, its caller function bc_svc_process() takes it from serv->sv_bc_xprt. The problem is that serv is global structure but sv_bc_xprt is assigned per-netnamespace. According to Trond, the whole "let's set up rqstp->rq_xprt for the back channel" is nothing but a giant hack in order to work around the fact that svc_process_common() uses it to find the xpt_ops, and perform a couple of (meaningless for the back channel) tests of xpt_flags. All we really need in svc_process_common() is to be able to run rqstp->rq_xprt->xpt_ops->xpo_prep_reply_hdr() Bruce J Fields points that this xpo_prep_reply_hdr() call is an awfully roundabout way just to do "svc_putnl(resv, 0);" in the tcp case. This patch does not initialiuze rqstp->rq_xprt in bc_svc_process(), now it calls svc_process_common() with rqstp->rq_xprt = NULL. To adjust reply header svc_process_common() just check rqstp->rq_prot and calls svc_tcp_prep_reply_hdr() for tcp case. To handle rqstp->rq_xprt = NULL case in functions called from svc_process_common() patch intruduces net namespace pointer svc_rqst->rq_bc_net and adjust SVC_NET() definition. Some other function was also adopted to properly handle described case. Signed-off-by: Vasily Averin Cc: stable@vger.kernel.org Fixes: 23c20ecd4475 ("NFS: callback up - users counting cleanup") Signed-off-by: J. Bruce Fields v2: - added lost extern svc_tcp_prep_reply_hdr() - dropped trace_svc_process() changes Signed-off-by: Vasily Averin Signed-off-by: Greg Kroah-Hartman

ext4: track writeback errors using the generic tracking infrastructure

2019-01-16T21:07:13Z

commit 95cb67138746451cc84cf8e516e14989746e93b0 upstream. We already using mapping_set_error() in fs/ext4/page_io.c, so all we need to do is to use file_check_and_advance_wb_err() when handling fsync() requests in ext4_sync_file(). Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman

ext4: use ext4_write_inode() when fsyncing w/o a journal

2019-01-16T21:07:13Z

commit ad211f3e94b314a910d4af03178a0b52a7d1ee0a upstream. In no-journal mode, we previously used __generic_file_fsync() in no-journal mode. This triggers a lockdep warning, and in addition, it's not safe to depend on the inode writeback mechanism in the case ext4. We can solve both problems by calling ext4_write_inode() directly. Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman

ext4: avoid kernel warning when writing the superblock to a dead device

2019-01-16T21:07:12Z

commit e86807862e6880809f191c4cea7f88a489f0ed34 upstream. The xfstests generic/475 test switches the underlying device with dm-error while running a stress test. This results in a large number of file system errors, and since we can't lock the buffer head when marking the superblock dirty in the ext4_grp_locked_error() case, it's possible the superblock to be !buffer_uptodate() without buffer_write_io_error() being true. We need to set buffer_uptodate() before we call mark_buffer_dirty() or this will trigger a WARN_ON. It's safe to do this since the superblock must have been properly read into memory or the mount would have been successful. So if buffer_uptodate() is not set, we can safely assume that this happened due to a failed attempt to write the superblock. Signed-off-by: Theodore Ts'o Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

ext4: fix a potential fiemap/page fault deadlock w/ inline_data

2019-01-16T21:07:12Z

commit 2b08b1f12cd664dc7d5c84ead9ff25ae97ad5491 upstream. The ext4_inline_data_fiemap() function calls fiemap_fill_next_extent() while still holding the xattr semaphore. This is not necessary and it triggers a circular lockdep warning. This is because fiemap_fill_next_extent() could trigger a page fault when it writes into page which triggers a page fault. If that page is mmaped from the inline file in question, this could very well result in a deadlock. This problem can be reproduced using generic/519 with a file system configuration which has the inline_data feature enabled. Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman

ext4: make sure enough credits are reserved for dioread_nolock writes

2019-01-16T21:07:12Z

commit 812c0cab2c0dfad977605dbadf9148490ca5d93f upstream. There are enough credits reserved for most dioread_nolock writes; however, if the extent tree is sufficiently deep, and/or quota is enabled, the code was not allowing for all eventualities when reserving journal credits for the unwritten extent conversion. This problem can be seen using xfstests ext4/034: WARNING: CPU: 1 PID: 257 at fs/ext4/ext4_jbd2.c:271 __ext4_handle_dirty_metadata+0x10c/0x180 Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work RIP: 0010:__ext4_handle_dirty_metadata+0x10c/0x180 ... EXT4-fs: ext4_free_blocks:4938: aborting transaction: error 28 in __ext4_handle_dirty_metadata EXT4: jbd2_journal_dirty_metadata failed: handle type 11 started at line 4921, credits 4/0, errcode -28 EXT4-fs error (device dm-1) in ext4_free_blocks:4950: error 28 Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman

rbd: don't return 0 on unmap if RBD_DEV_FLAG_REMOVING is set

2019-01-16T21:07:12Z

commit 85f5a4d666fd9be73856ed16bb36c5af5b406b29 upstream. There is a window between when RBD_DEV_FLAG_REMOVING is set and when the device is removed from rbd_dev_list. During this window, we set "already" and return 0. Returning 0 from write(2) can confuse userspace tools because 0 indicates that nothing was written. In particular, "rbd unmap" will retry the write multiple times a second: 10:28:05.463299 write(4, "0", 1) = 0 10:28:05.463509 write(4, "0", 1) = 0 10:28:05.463720 write(4, "0", 1) = 0 10:28:05.463942 write(4, "0", 1) = 0 10:28:05.464155 write(4, "0", 1) = 0 Cc: stable@vger.kernel.org Signed-off-by: Ilya Dryomov Tested-by: Dongsheng Yang Signed-off-by: Greg Kroah-Hartman

drm/fb-helper: Partially bring back workaround for bugs of SDL 1.2

2019-01-16T21:07:12Z

commit 62d85b3bf9d978ed4b6b2aeef5cf0ccf1423906e upstream. SDL 1.2 sets all fields related to the pixel format to zero in some cases[1]. Prior to commit db05c48197759 ("drm: fb-helper: Reject all pixel format changing requests"), there was an unintentional workaround for this that existed for more than a decade. First in device-specific DRM drivers, then here in drm_fb_helper.c. Previous code containing this workaround just ignores pixel format fields from userspace code. Not a good thing either, as this way, driver may silently use pixel format different from what client actually requested, and this in turn will lead to displaying garbage on the screen. I think that returning EINVAL to userspace in this particular case is the right option, so I decided to left code from problematic commit untouched instead of just reverting it entirely. Here is the steps required to reproduce this problem exactly: 1) Compile fceux[2] with SDL 1.2.15 and without GTK or OpenGL support. SDL should be compiled with fbdev support (which is on by default). 2) Create /etc/fb.modes with following contents (values seems not used, and just required to trigger problematic code in SDL): mode "test" geometry 1 1 1 1 1 timings 1 1 1 1 1 1 1 endmode 3) Create ~/.fceux/fceux.cfg with following contents: SDL.Hotkeys.Quit = 27 SDL.DoubleBuffering = 1 4) Ensure that screen resolution is at least 1280x960 (e.g. append "video=Virtual-1:1280x960-32" to the kernel cmdline for qemu/QXL). 5) Try to run fceux on VT with some ROM file[3]: # ./fceux color_test.nes [1] SDL 1.2.15 source code, src/video/fbcon/SDL_fbvideo.c, FB_SetVideoMode() [2] http://www.fceux.com [3] Example ROM: https://github.com/bokuweb/rustynes/blob/master/roms/color_test.nes Reported-by: saahriktu Suggested-by: saahriktu Cc: stable@vger.kernel.org Fixes: db05c48197759 ("drm: fb-helper: Reject all pixel format changing requests") Signed-off-by: Ivan Mironov [danvet: Delete misleading comment.] Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20190108072353.28078-2-mironov.ivan@gmail.com Link: https://patchwork.freedesktop.org/patch/msgid/20190108072353.28078-2-mironov.ivan@gmail.com Signed-off-by: Greg Kroah-Hartman