Skip to content

L
linux
Switch branch/tag
  1. 19 Aug, 2022 3 commits
    • Sean Christopherson's avatar
      KVM: Move coalesced MMIO initialization (back) into kvm_create_vm() · c2b82397
      Sean Christopherson authored 
      Invoke kvm_coalesced_mmio_init() from kvm_create_vm() now that allocating
and initializing coalesced MMIO objects is separate from registering any
associated devices.  Moving coalesced MMIO cleans up the last oddity
where KVM does VM creation/initialization after kvm_create_vm(), and more
importantly after kvm_arch_post_init_vm() is called and the VM is added
to the global vm_list, i.e. after the VM is fully created as far as KVM
is concerned.

Originally, kvm_coalesced_mmio_init() was called by kvm_create_vm(), but
the original implementation was completely devoid of error handling.
Commit 6ce5a090 ("KVM: coalesced_mmio: fix kvm_coalesced_mmio_init()'s
error handling" fixed the various bugs, and in doing so rightly moved the
call to after kvm_create_vm() because kvm_coalesced_mmio_init() also
registered the coalesced MMIO device.  Commit 2b3c246a ("KVM: Make
coalesced mmio use a device per zone") cleaned up that mess by having
each zone register a separate device, i.e. moved device registration to
its logical home in kvm_vm_ioctl_register_coalesced_mmio().  As a result,
kvm_coalesced_mmio_init() is now a "pure" initialization helper and can
be safely called from kvm_create_vm().

Opportunstically drop the #ifdef, KVM provides stubs for
kvm_coalesced_mmio_{init,free}() when CONFIG_KVM_MMIO=n (s390).
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20220816053937.2477106-4-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      c2b82397
    • Sean Christopherson's avatar
      KVM: Unconditionally get a ref to /dev/kvm module when creating a VM · 405294f2
      Sean Christopherson authored 
      Unconditionally get a reference to the /dev/kvm module when creating a VM
instead of using try_get_module(), which will fail if the module is in
the process of being forcefully unloaded.  The error handling when
try_get_module() fails doesn't properly unwind all that has been done,
e.g. doesn't call kvm_arch_pre_destroy_vm() and doesn't remove the VM
from the global list.  Not removing VMs from the global list tends to be
fatal, e.g. leads to use-after-free explosions.

The obvious alternative would be to add proper unwinding, but the
justification for using try_get_module(), "rmmod --wait", is completely
bogus as support for "rmmod --wait", i.e. delete_module() without
O_NONBLOCK, was removed by commit 3f2b9c9c ("module: remove rmmod
--wait option.") nearly a decade ago.

It's still possible for try_get_module() to fail due to the module dying
(more like being killed), as the module will be tagged MODULE_STATE_GOING
by "rmmod --force", i.e. delete_module(..., O_TRUNC), but playing nice
with forced unloading is an exercise in futility and gives a falsea sense
of security.  Using try_get_module() only prevents acquiring _new_
references, it doesn't magically put the references held by other VMs,
and forced unloading doesn't wait, i.e. "rmmod --force" on KVM is all but
guaranteed to cause spectacular fireworks; the window where KVM will fail
try_get_module() is tiny compared to the window where KVM is building and
running the VM with an elevated module refcount.

Addressing KVM's inability to play nice with "rmmod --force" is firmly
out-of-scope.  Forcefully unloading any module taints kernel (for obvious
reasons)  _and_ requires the kernel to be built with
CONFIG_MODULE_FORCE_UNLOAD=y, which is off by default and comes with the
amusing disclaimer that it's "mainly for kernel developers and desperate
users".  In other words, KVM is free to scoff at bug reports due to using
"rmmod --force" while VMs may be running.

Fixes: 5f6de5cb ("KVM: Prevent module exit until all VMs are freed")
Cc: stable@vger.kernel.org
Cc: David Matlack <dmatlack@google.com>
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20220816053937.2477106-3-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      405294f2
    • Sean Christopherson's avatar
      KVM: Properly unwind VM creation if creating debugfs fails · 4ba4f419
      Sean Christopherson authored 
      Properly unwind VM creation if kvm_create_vm_debugfs() fails.  A recent
change to invoke kvm_create_vm_debug() in kvm_create_vm() was led astray
by buggy try_get_module() handling adding by commit 5f6de5cb ("KVM:
Prevent module exit until all VMs are freed").  The debugfs error path
effectively inherits the bad error path of try_module_get(), e.g. KVM
leaves the to-be-free VM on vm_list even though KVM appears to do the
right thing by calling module_put() and falling through.

Opportunistically hoist kvm_create_vm_debugfs() above the call to
kvm_arch_post_init_vm() so that the "post-init" arch hook is actually
invoked after the VM is initialized (ignoring kvm_coalesced_mmio_init()
for the moment).  x86 is the only non-nop implementation of the post-init
hook, and it doesn't allocate/initialize any objects that are reachable
via debugfs code (spawns a kthread worker for the NX huge page mitigation).

Leave the buggy try_get_module() alone for now, it will be fixed in a
separate commit.

Fixes: b74ed7a6 ("KVM: Actually create debugfs in kvm_create_vm()")
Reported-by: syzbot+744e173caec2e1627ee0@syzkaller.appspotmail.com
Cc: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Reviewed-by: default avatarOliver Upton <oliver.upton@linux.dev>
Message-Id: <20220816053937.2477106-2-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      4ba4f419
  3. 14 Aug, 2022 10 commits
    • Linus Torvalds's avatar
      Linux 6.0-rc1 · 568035b0
      Linus Torvalds authored
      568035b0
    • Yury Norov's avatar
      radix-tree: replace gfp.h inclusion with gfp_types.h · 9f162193
      Yury Norov authored 
      Radix tree header includes gfp.h for __GFP_BITS_SHIFT only. Now we
have gfp_types.h for this.

Fixes powerpc allmodconfig build:

   In file included from include/linux/nodemask.h:97,
                    from include/linux/mmzone.h:17,
                    from include/linux/gfp.h:7,
                    from include/linux/radix-tree.h:12,
                    from include/linux/idr.h:15,
                    from include/linux/kernfs.h:12,
                    from include/linux/sysfs.h:16,
                    from include/linux/kobject.h:20,
                    from include/linux/pci.h:35,
                    from arch/powerpc/kernel/prom_init.c:24:
   include/linux/random.h: In function 'add_latent_entropy':
>> include/linux/random.h:25:46: error: 'latent_entropy' undeclared (first use in this function); did you mean 'add_latent_entropy'?
      25 |         add_device_randomness((const void *)&latent_entropy, sizeof(latent_entropy));
         |                                              ^~~~~~~~~~~~~~
         |                                              add_latent_entropy
   include/linux/random.h:25:46: note: each undeclared identifier is reported only once for each function it appears in
Reported-by: default avatarkernel test robot <lkp@intel.com>
CC: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: default avatarYury Norov <yury.norov@gmail.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9f162193
    • Linus Torvalds's avatar
      Merge tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs · 74cbb480
      Linus Torvalds authored 
      Pull vfs lseek fix from Al Viro:
 "Fix proc_reg_llseek() breakage. Always had been possible if somebody
  left NULL ->proc_lseek, became a practical issue now"

* tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  take care to handle NULL ->proc_lseek()
      74cbb480
    • Al Viro's avatar
      take care to handle NULL ->proc_lseek() · 3f61631d
      Al Viro authored 
      Easily done now, just by clearing FMODE_LSEEK in ->f_mode
during proc_reg_open() for such entries.

Fixes: 868941b1 "fs: remove no_llseek"
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      3f61631d
    • Linus Torvalds's avatar
      Merge tag 'for-linus-6.0-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip · 5d6a0f4d
      Linus Torvalds authored 
      Pull more xen updates from Juergen Gross:

 - fix the handling of the "persistent grants" feature negotiation
   between Xen blkfront and Xen blkback drivers

 - a cleanup of xen.config and adding xen.config to Xen section in
   MAINTAINERS

 - support HVMOP_set_evtchn_upcall_vector, which is more compliant to
   "normal" interrupt handling than the global callback used up to now

 - further small cleanups

* tag 'for-linus-6.0-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  MAINTAINERS: add xen config fragments to XEN HYPERVISOR sections
  xen: remove XEN_SCRUB_PAGES in xen.config
  xen/pciback: Fix comment typo
  xen/xenbus: fix return type in xenbus_file_read()
  xen-blkfront: Apply 'feature_persistent' parameter when connect
  xen-blkback: Apply 'feature_persistent' parameter when connect
  xen-blkback: fix persistent grants negotiation
  x86/xen: Add support for HVMOP_set_evtchn_upcall_vector
      5d6a0f4d
    • Linus Torvalds's avatar
      Merge tag 'perf-tools-fixes-for-v6.0-2022-08-13' of... · 96f86ff0
      Linus Torvalds authored 
      Merge tag 'perf-tools-fixes-for-v6.0-2022-08-13' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux

Pull more perf tool updates from Arnaldo Carvalho de Melo:

 - 'perf c2c' now supports ARM64, adjust its output to cope with
   differences with what is in x86_64. Now go find false sharing on
   ARM64 (at least Neoverse) as well!

 - Refactor the JSON processing, making the output more compact and thus
   reducing the size of the resulting perf binary

 - Improvements for 'perf offcpu' profiling, including tracking child
   processes

 - Update Intel JSON metrics and events files for broadwellde,
   broadwellx, cascadelakex, haswellx, icelakex, ivytown, jaketown,
   knightslanding, sapphirerapids, skylakex and snowridgex

 - Add 'perf stat' JSON output and a 'perf test' entry for it

 - Ignore memfd and anonymous mmap events if jitdump present

 - Refactor 'perf test' shell tests allowing subdirs

 - Fix an error handling path in 'parse_perf_probe_command()'

 - Fixes for the guest Intel PT tracing patchkit in the 1st batch of
   this merge window

 - Print debuginfod queries if -v option is used, to explain delays in
   processing when debuginfo servers are enabled to fetch DSOs with
   richer symbol tables

 - Improve error message for 'perf record -p not_existing_pid'

 - Fix openssl and libbpf feature detection

 - Add PMU pai_crypto event description for IBM z16 on 'perf list'

 - Fix typos and duplicated words on comments in various places

* tag 'perf-tools-fixes-for-v6.0-2022-08-13' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux: (81 commits)
  perf test: Refactor shell tests allowing subdirs
  perf vendor events: Update events for snowridgex
  perf vendor events: Update events and metrics for skylakex
  perf vendor events: Update metrics for sapphirerapids
  perf vendor events: Update events for knightslanding
  perf vendor events: Update metrics for jaketown
  perf vendor events: Update metrics for ivytown
  perf vendor events: Update events and metrics for icelakex
  perf vendor events: Update events and metrics for haswellx
  perf vendor events: Update events and metrics for cascadelakex
  perf vendor events: Update events and metrics for broadwellx
  perf vendor events: Update metrics for broadwellde
  perf jevents: Fold strings optimization
  perf jevents: Compress the pmu_events_table
  perf metrics: Copy entire pmu_event in find metric
  perf pmu-events: Hide the pmu_events
  perf pmu-events: Don't assume pmu_event is an array
  perf pmu-events: Move test events/metrics to JSON
  perf test: Use full metric resolution
  perf pmu-events: Hide pmu_events_map
  ...
      96f86ff0
    • Linus Torvalds's avatar
      Merge tag 'powerpc-6.0-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux · d785610f
      Linus Torvalds authored 
      Pull powerpc fixes from Michael Ellerman:

 - Ensure we never emit lwarx with EH=1 on 32-bit, because some 32-bit
   CPUs trap on it rather than ignoring it as they should.

 - Fix ftrace when building with clang, which was broken by some
   refactoring.

 - A couple of other minor fixes.

Thanks to Christophe Leroy, Naveen N.  Rao, Nick Desaulniers, Ondrej
Mosnacek, Pali Rohár, Russell Currey, and Segher Boessenkool.

* tag 'powerpc-6.0-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/kexec: Fix build failure from uninitialised variable
  powerpc/ppc-opcode: Fix PPC_RAW_TW()
  powerpc64/ftrace: Fix ftrace for clang builds
  powerpc: Make eh value more explicit when using lwarx
  powerpc: Don't hide eh field of lwarx behind a macro
  powerpc: Fix eh field when calling lwarx on PPC32
      d785610f
    • Linus Torvalds's avatar
      Merge tag 'pull-work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs · aea23e7c
      Linus Torvalds authored 
      Pull /proc/mounts fix from Al Viro:
 "Fix for /proc/mounts escaping - escape the '#' character too"

* tag 'pull-work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  vfs: escape hash as well
      aea23e7c
    • Linus Torvalds's avatar
      Merge tag '5.20-rc-smb3-client-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6 · 332019e2
      Linus Torvalds authored 
      Pull more cifs updates from Steve French:

 - two fixes for stable, one for a lock length miscalculation, and
   another fixes a lease break timeout bug

 - improvement to handle leases, allows the close timeout to be
   configured more safely

 - five restructuring/cleanup patches

* tag '5.20-rc-smb3-client-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: Do not access tcon->cfids->cfid directly from is_path_accessible
  cifs: Add constructor/destructors for tcon->cfid
  SMB3: fix lease break timeout when multiple deferred close handles for the same file.
  smb3: allow deferred close timeout to be configurable
  cifs: Do not use tcon->cfid directly, use the cfid we get from open_cached_dir
  cifs: Move cached-dir functions into a separate file
  cifs: Remove {cifs,nfs}_fscache_release_page()
  cifs: fix lock length calculation
      332019e2
    • David Howells's avatar
      afs: Enable multipage folio support · 8549a263
      David Howells authored 
      Enable multipage folio support for the afs filesystem.

Support has already been implemented in netfslib, fscache and cachefiles
and in most of afs, but I've waited for Matthew Wilcox's latest folio
changes.

Note that it does require a change to afs_write_begin() to return the
correct subpage.  This is a "temporary" change as we're working on
getting rid of the need for ->write_begin() and ->write_end()
completely, at least as far as network filesystems are concerned - but
it doesn't prevent afs from making use of the capability.
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Acked-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: kafs-testing@auristor.com
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/lkml/2274528.1645833226@warthog.procyon.org.uk/Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8549a263
  5. 13 Aug, 2022 27 commits
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7