1. 04 Feb, 2022 5 commits
  2. 03 Feb, 2022 6 commits
    • Mickaël Salaün's avatar
      printk: Fix incorrect __user type in proc_dointvec_minmax_sysadmin() · 1f2cfdd3
      Mickaël Salaün authored
      The move of proc_dointvec_minmax_sysadmin() from kernel/sysctl.c to
      kernel/printk/sysctl.c introduced an incorrect __user attribute to the
      buffer argument.  I spotted this change in [1] as well as the kernel
      test robot.  Revert this change to please sparse:
      
        kernel/printk/sysctl.c:20:51: warning: incorrect type in argument 3 (different address spaces)
        kernel/printk/sysctl.c:20:51:    expected void *
        kernel/printk/sysctl.c:20:51:    got void [noderef] __user *buffer
      
      Fixes: faaa357a ("printk: move printk sysctl to printk/sysctl.c")
      Link: https://lore.kernel.org/r/20220104155024.48023-2-mic@digikod.net [1]
      Reported-by: default avatarkernel test robot <lkp@intel.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: John Ogness <john.ogness@linutronix.de>
      Cc: Luis Chamberlain <mcgrof@kernel.org>
      Cc: Petr Mladek <pmladek@suse.com>
      Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Xiaoming Ni <nixiaoming@huawei.com>
      Signed-off-by: default avatarMickaël Salaün <mic@linux.microsoft.com>
      Link: https://lore.kernel.org/r/20220203145029.272640-1-mic@digikod.netSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      1f2cfdd3
    • Igor Pylypiv's avatar
      Revert "module, async: async_synchronize_full() on module init iff async is used" · 67d6212a
      Igor Pylypiv authored
      This reverts commit 774a1221.
      
      We need to finish all async code before the module init sequence is
      done.  In the reverted commit the PF_USED_ASYNC flag was added to mark a
      thread that called async_schedule().  Then the PF_USED_ASYNC flag was
      used to determine whether or not async_synchronize_full() needs to be
      invoked.  This works when modprobe thread is calling async_schedule(),
      but it does not work if module dispatches init code to a worker thread
      which then calls async_schedule().
      
      For example, PCI driver probing is invoked from a worker thread based on
      a node where device is attached:
      
      	if (cpu < nr_cpu_ids)
      		error = work_on_cpu(cpu, local_pci_probe, &ddi);
      	else
      		error = local_pci_probe(&ddi);
      
      We end up in a situation where a worker thread gets the PF_USED_ASYNC
      flag set instead of the modprobe thread.  As a result,
      async_synchronize_full() is not invoked and modprobe completes without
      waiting for the async code to finish.
      
      The issue was discovered while loading the pm80xx driver:
      (scsi_mod.scan=async)
      
      modprobe pm80xx                      worker
      ...
        do_init_module()
        ...
          pci_call_probe()
            work_on_cpu(local_pci_probe)
                                           local_pci_probe()
                                             pm8001_pci_probe()
                                               scsi_scan_host()
                                                 async_schedule()
                                                 worker->flags |= PF_USED_ASYNC;
                                           ...
            < return from worker >
        ...
        if (current->flags & PF_USED_ASYNC) <--- false
        	async_synchronize_full();
      
      Commit 21c3c5d2 ("block: don't request module during elevator init")
      fixed the deadlock issue which the reverted commit 774a1221
      ("module, async: async_synchronize_full() on module init iff async is
      used") tried to fix.
      
      Since commit 0fdff3ec ("async, kmod: warn on synchronous
      request_module() from async workers") synchronous module loading from
      async is not allowed.
      
      Given that the original deadlock issue is fixed and it is no longer
      allowed to call synchronous request_module() from async we can remove
      PF_USED_ASYNC flag to make module init consistently invoke
      async_synchronize_full() unless async module probe is requested.
      Signed-off-by: default avatarIgor Pylypiv <ipylypiv@google.com>
      Reviewed-by: default avatarChangyuan Lyu <changyuanl@google.com>
      Reviewed-by: default avatarLuis Chamberlain <mcgrof@kernel.org>
      Acked-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      67d6212a
    • Linus Torvalds's avatar
      Merge branch 'for-5.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup · 305e6c42
      Linus Torvalds authored
      Pull cgroup fixes from Tejun Heo:
      
       - Eric's fix for a long standing cgroup1 permission issue where it only
         checks for uid 0 instead of CAP which inadvertently allows
         unprivileged userns roots to modify release_agent userhelper
      
       - Fixes for the fallout from Waiman's recent cpuset work
      
      * 'for-5.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
        cgroup/cpuset: Fix "suspicious RCU usage" lockdep warning
        cgroup-v1: Require capabilities to set release_agent
        cpuset: Fix the bug that subpart_cpus updated wrongly in update_cpumask()
        cgroup/cpuset: Make child cpusets restrict parents on v1 hierarchy
      305e6c42
    • Waiman Long's avatar
      cgroup/cpuset: Fix "suspicious RCU usage" lockdep warning · 2bdfd282
      Waiman Long authored
      It was found that a "suspicious RCU usage" lockdep warning was issued
      with the rcu_read_lock() call in update_sibling_cpumasks().  It is
      because the update_cpumasks_hier() function may sleep. So we have
      to release the RCU lock, call update_cpumasks_hier() and reacquire
      it afterward.
      
      Also add a percpu_rwsem_assert_held() in update_sibling_cpumasks()
      instead of stating that in the comment.
      
      Fixes: 4716909c ("cpuset: Track cpusets that use parent's effective_cpus")
      Signed-off-by: default avatarWaiman Long <longman@redhat.com>
      Tested-by: default avatarPhil Auld <pauld@redhat.com>
      Reviewed-by: default avatarPhil Auld <pauld@redhat.com>
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      2bdfd282
    • John Hubbard's avatar
      Revert "mm/gup: small refactoring: simplify try_grab_page()" · c36c04c2
      John Hubbard authored
      This reverts commit 54d516b1
      
      That commit did a refactoring that effectively combined fast and slow
      gup paths (again).  And that was again incorrect, for two reasons:
      
       a) Fast gup and slow gup get reference counts on pages in different
          ways and with different goals: see Linus' writeup in commit
          cd1adf1b ("Revert "mm/gup: remove try_get_page(), call
          try_get_compound_head() directly""), and
      
       b) try_grab_compound_head() also has a specific check for
          "FOLL_LONGTERM && !is_pinned(page)", that assumes that the caller
          can fall back to slow gup. This resulted in new failures, as
          recently report by Will McVicker [1].
      
      But (a) has problems too, even though they may not have been reported
      yet.  So just revert this.
      
      Link: https://lore.kernel.org/r/20220131203504.3458775-1-willmcvicker@google.com [1]
      Fixes: 54d516b1 ("mm/gup: small refactoring: simplify try_grab_page()")
      Reported-and-tested-by: default avatarWill McVicker <willmcvicker@google.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Cc: Minchan Kim <minchan@google.com>
      Cc: Matthew Wilcox <willy@infradead.org>
      Cc: Christian Borntraeger <borntraeger@de.ibm.com>
      Cc: Heiko Carstens <hca@linux.ibm.com>
      Cc: Vasily Gorbik <gor@linux.ibm.com>
      Cc: stable@vger.kernel.org # 5.15
      Signed-off-by: default avatarJohn Hubbard <jhubbard@nvidia.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c36c04c2
    • Linus Torvalds's avatar
      Merge tag 'mips-fixes-5.17_2' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux · d394bb77
      Linus Torvalds authored
      Pull MIPS fixes from Thomas Bogendoerfer:
      
       - fix missed change for PTR->PTR_WD conversion
      
       - kernel-doc fixes
      
      * tag 'mips-fixes-5.17_2' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
        MIPS: KVM: fix vz.c kernel-doc notation
        MIPS: octeon: Fix missed PTR->PTR_WD conversion
      d394bb77
  3. 02 Feb, 2022 4 commits
  4. 01 Feb, 2022 12 commits
  5. 31 Jan, 2022 2 commits
  6. 30 Jan, 2022 11 commits