1. 01 Sep, 2022 3 commits
    • Linus Torvalds's avatar
      Merge tag 'slab-for-6.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab · d330076e
      Linus Torvalds authored
      Pull slab fix from Vlastimil Babka:
      
       - A fix from Waiman Long to avoid a theoretical deadlock reported by
         lockdep.
      
      * tag 'slab-for-6.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
        mm/slab_common: Deleting kobject in kmem_cache_destroy() without holding slab_mutex/cpu_hotplug_lock
      d330076e
    • Linus Torvalds's avatar
      Merge tag 'sound-6.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound · 2880e1a1
      Linus Torvalds authored
      Pull sound fixes from Takashi Iwai:
       "Just handful changes at this time. The only major change is the
        regression fix about the x86 WC-page buffer allocation.
      
        The rest are trivial data-race fixes for ALSA sequencer core, the
        possible out-of-bounds access fixes in the new ALSA control hash code,
        and a few device-specific workarounds and fixes"
      
      * tag 'sound-6.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
        ALSA: usb-audio: Add quirk for LH Labs Geek Out HD Audio 1V5
        ALSA: hda/realtek: Add speaker AMP init for Samsung laptops with ALC298
        ALSA: control: Re-order bounds checking in get_ctl_id_hash()
        ALSA: control: Fix an out-of-bounds bug in get_ctl_id_hash()
        ALSA: hda: intel-nhlt: Correct the handling of fmt_config flexible array
        ALSA: seq: Fix data-race at module auto-loading
        ALSA: seq: oss: Fix data-race for max_midi_devs access
        ALSA: memalloc: Revive x86-specific WC page allocations again
      2880e1a1
    • Waiman Long's avatar
      mm/slab_common: Deleting kobject in kmem_cache_destroy() without holding... · 0495e337
      Waiman Long authored
      mm/slab_common: Deleting kobject in kmem_cache_destroy() without holding slab_mutex/cpu_hotplug_lock
      
      A circular locking problem is reported by lockdep due to the following
      circular locking dependency.
      
        +--> cpu_hotplug_lock --> slab_mutex --> kn->active --+
        |                                                     |
        +-----------------------------------------------------+
      
      The forward cpu_hotplug_lock ==> slab_mutex ==> kn->active dependency
      happens in
      
        kmem_cache_destroy():	cpus_read_lock(); mutex_lock(&slab_mutex);
        ==> sysfs_slab_unlink()
            ==> kobject_del()
                ==> kernfs_remove()
      	      ==> __kernfs_remove()
      	          ==> kernfs_drain(): rwsem_acquire(&kn->dep_map, ...);
      
      The backward kn->active ==> cpu_hotplug_lock dependency happens in
      
        kernfs_fop_write_iter(): kernfs_get_active();
        ==> slab_attr_store()
            ==> cpu_partial_store()
                ==> flush_all(): cpus_read_lock()
      
      One way to break this circular locking chain is to avoid holding
      cpu_hotplug_lock and slab_mutex while deleting the kobject in
      sysfs_slab_unlink() which should be equivalent to doing a write_lock
      and write_unlock pair of the kn->active virtual lock.
      
      Since the kobject structures are not protected by slab_mutex or the
      cpu_hotplug_lock, we can certainly release those locks before doing
      the delete operation.
      
      Move sysfs_slab_unlink() and sysfs_slab_release() to the newly
      created kmem_cache_release() and call it outside the slab_mutex &
      cpu_hotplug_lock critical sections. There will be a slight delay
      in the deletion of sysfs files if kmem_cache_release() is called
      indirectly from a work function.
      
      Fixes: 5a836bf6 ("mm: slub: move flush_cpu_slab() invocations __free_slab() invocations out of IRQ context")
      Signed-off-by: default avatarWaiman Long <longman@redhat.com>
      Reviewed-by: default avatarHyeonggon Yoo <42.hyeyoo@gmail.com>
      Reviewed-by: default avatarRoman Gushchin <roman.gushchin@linux.dev>
      Acked-by: default avatarDavid Rientjes <rientjes@google.com>
      Link: https://lore.kernel.org/all/YwOImVd+nRUsSAga@hyeyoo/Signed-off-by: default avatarVlastimil Babka <vbabka@suse.cz>
      0495e337
  2. 31 Aug, 2022 8 commits
  3. 29 Aug, 2022 2 commits
  4. 28 Aug, 2022 27 commits