There is no operation to order with afterwards, and removing the flag is
not critical in any way.
There will always be a "race condition" where the application will
trigger IORING_ENTER_SQ_WAKEUP when it isn't actually needed.
Signed-off-by: Stefan Bühler <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
smp_store_release in io_commit_sqring already orders the store to
dropped before the update to SQ head.
Signed-off-by: Stefan Bühler <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
The memory operations before reading cq head are unrelated and we
don't care about their order.
Document that the control dependency in combination with READ_ONCE and
WRITE_ONCE forms a barrier we need.
Signed-off-by: Stefan Bühler <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
wq_has_sleeper has a full barrier internally. The smp_rmb barrier in
io_uring_poll synchronizes with it.
Signed-off-by: Stefan Bühler <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
The application reading the CQ ring needs a barrier to pair with the
smp_store_release in io_commit_cqring, not the barrier after it.
Also a write barrier *after* writing something (but not *before*
writing anything interesting) doesn't order anything, so an smp_wmb()
after writing SQ tail is not needed.
Additionally consider reading SQ head and writing CQ tail in the notes.
Also add some clarifications how the various other fields in the ring
buffers are used.
Signed-off-by: Stefan Bühler <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
Not all request types set REQ_F_FORCE_NONBLOCK when they needed async
punting; reverse logic instead and set REQ_F_NOWAIT if request mustn't
be punted.
Signed-off-by: Stefan Bühler <[email protected]>
Merged with my previous patch for this.
Signed-off-by: Jens Axboe <[email protected]>
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Merge tag 'selinux-pr-20190429' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux fix from Paul Moore:
"One small patch for the stable folks to fix a problem when building
against the latest glibc.
I'll be honest and say that I'm not really thrilled with the idea of
sending this up right now, but Greg is a little annoyed so here I
figured I would at least send this"
* tag 'selinux-pr-20190429' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
selinux: use kernel linux/socket.h for genheaders and mdp
Instead of always going via arch_counter_get_cntvct_stable to access the
counter workaround, let's have arch_timer_read_counter point to the
right method.
For that, we need to track whether any CPU in the system has a
workaround for the counter. This is done by having an atomic variable
tracking this.
Acked-by: Mark Rutland <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
The use of a static key in a hotplug path has proved to be a real
nightmare, and makes it impossible to have scream-free lockdep
kernel.
Let's remove the static key altogether, and focus on something saner.
Acked-by: Mark Rutland <[email protected]>
Acked-by: Daniel Lezcano <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
Let's start with the removal of the arch_timer_read_ool_enabled
static key in arch_timer_reg_read_stable. It is not a fast path,
and we can simplify things a bit.
Acked-by: Mark Rutland <[email protected]>
Acked-by: Daniel Lezcano <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
When a given timer is affected by an erratum and requires an
alternative implementation of set_next_event, we do a rather
complicated dance to detect and call the workaround on each
set_next_event call.
This is clearly idiotic, as we can perfectly detect whether
this CPU requires a workaround while setting up the clock event
device.
This only requires the CPU-specific detection to be done a bit
earlier, and we can then safely override the set_next_event pointer
if we have a workaround associated to that CPU.
Acked-by: Mark Rutland <[email protected]>
Acked-by; Daniel Lezcano <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
Only arch_timer_read_counter will guarantee that workarounds are
applied. So let's use this one instead of arch_counter_get_cntvct.
Acked-by: Mark Rutland <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
If register_snap_client fails in atalk_init,
error code should be set, otherwise it will
triggers NULL pointer dereference while unloading
module.
Fixes: 9804501fa1 ("appletalk: Fix potential NULL pointer dereference in unregister_snap_client")
Signed-off-by: YueHaibing <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Only arch_timer_read_counter will guarantee that workarounds are
applied. So let's use this one instead of arch_counter_get_cntvct.
Acked-by: Mark Rutland <[email protected]>
Reviewed-by: Guenter Roeck <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
The VDSO code uses the kernel helper that was originally designed
to abstract the access between 32 and 64bit systems. It worked so
far because this function is declared as 'inline'.
As we're about to revamp that part of the code, the VDSO would
break. Let's fix it by doing what should have been done from
the start, a proper system register access.
Reviewed-by: Mark Rutland <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
The "fs->location" is a u32 that comes from the user in ethtool_set_rxnfc().
We can't pass unclamped values to test_bit() or it results in an out of
bounds access beyond the end of the bitmap.
Fixes: 7318166cac ("net: dsa: bcm_sf2: Add support for ethtool::rxnfc")
Signed-off-by: Dan Carpenter <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
In rxrpc_destroy_all_calls(), there are two phases: (1) make sure the
->calls list is empty, emitting error messages if not, and (2) wait for the
RCU cleanup to happen on outstanding calls (ie. ->nr_calls becomes 0).
To avoid taking the call_lock, the function prechecks ->calls and if empty,
it returns to avoid taking the lock - this is wrong, however: it still
needs to go and do the second phase and wait for ->nr_calls to become 0.
Without this, the rxrpc_net struct may get deallocated before we get to the
RCU cleanup for the last calls. This can lead to:
Slab corruption (Not tainted): kmalloc-16k start=ffff88802b178000, len=16384
050: 6b 6b 6b 6b 6b 6b 6b 6b 61 6b 6b 6b 6b 6b 6b 6b kkkkkkkkakkkkkkk
Note the "61" at offset 0x58. This corresponds to the ->nr_calls member of
struct rxrpc_net (which is >9k in size, and thus allocated out of the 16k
slab).
Fix this by flipping the condition on the if-statement, putting the locked
section inside the if-body and dropping the return from there. The
function will then always go on to wait for the RCU cleanup on outstanding
calls.
Fixes: 2baec2c3f8 ("rxrpc: Support network namespacing")
Signed-off-by: David Howells <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Neoverse-N1 is also affected by ARM64_ERRATUM_1188873, so let's
add it to the list of affected CPUs.
Signed-off-by: Marc Zyngier <[email protected]>
[will: Update silicon-errata.txt]
Signed-off-by: Will Deacon <[email protected]>
Since ARM64_ERRATUM_1188873 only affects AArch32 EL0, it makes some
sense that it should depend on COMPAT.
Signed-off-by: Marc Zyngier <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
We currently deal with ARM64_ERRATUM_1188873 by always trapping EL0
accesses for both instruction sets. Although nothing wrong comes out
of that, people trying to squeeze the last drop of performance from
buggy HW find this over the top. Oh well.
Let's change the mitigation by flipping the counter enable bit
on return to userspace. Non-broken HW gets an extra branch on
the fast path, which is hopefully not the end of the world.
The arch timer workaround is also removed.
Acked-by: Daniel Lezcano <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
Steffen Klassert says:
====================
pull request (net): ipsec 2019-04-30
1) Fix an out-of-bound array accesses in __xfrm_policy_unlink.
From YueHaibing.
2) Reset the secpath on failure in the ESP GRO handlers
to avoid dereferencing an invalid pointer on error.
From Myungho Jung.
3) Add and revert a patch that tried to add rcu annotations
to netns_xfrm. From Su Yanjun.
4) Wait for rcu callbacks before freeing xfrm6_tunnel_spi_kmem.
From Su Yanjun.
5) Fix forgotten vti4 ipip tunnel deregistration.
From Jeremy Sowden:
6) Remove some duplicated log messages in vti4.
From Jeremy Sowden.
7) Don't use IPSEC_PROTO_ANY when flushing states because
this will flush only IPsec portocol speciffic states.
IPPROTO_ROUTING states may remain in the lists when
doing net exit. Fix this by replacing IPSEC_PROTO_ANY
with zero. From Cong Wang.
8) Add length check for UDP encapsulation to fix "Oversized IP packet"
warnings on receive side. From Sabrina Dubroca.
9) Fix xfrm interface lookup when the interface is associated to
a vrf layer 3 master device. From Martin Willi.
10) Reload header pointers after pskb_may_pull() in _decode_session4(),
otherwise we may read from uninitialized memory.
11) Update the documentation about xfrm[46]_gc_thresh, it
is not used anymore after the flowcache removal.
From Nicolas Dichtel.
====================
Signed-off-by: David S. Miller <[email protected]>
As of commit ece0e2b640 ("mm: remove pte_*map_nested()"),
pte_unmap_nested() is no longer used and can be removed from the arm64
code.
Signed-off-by: Qian Cai <[email protected]>
[will: also remove pte_offset_map_nested()]
Signed-off-by: Will Deacon <[email protected]>
When building with -Wunused-but-set-variable, the compiler shouts about
a number of pte_unmap() users, since this expands to an empty macro on
arm64:
| mm/gup.c: In function 'gup_pte_range':
| mm/gup.c:1727:16: warning: variable 'ptem' set but not used
| [-Wunused-but-set-variable]
| mm/gup.c: At top level:
| mm/memory.c: In function 'copy_pte_range':
| mm/memory.c:821:24: warning: variable 'orig_dst_pte' set but not used
| [-Wunused-but-set-variable]
| mm/memory.c:821:9: warning: variable 'orig_src_pte' set but not used
| [-Wunused-but-set-variable]
| mm/swap_state.c: In function 'swap_ra_info':
| mm/swap_state.c:641:15: warning: variable 'orig_pte' set but not used
| [-Wunused-but-set-variable]
| mm/madvise.c: In function 'madvise_free_pte_range':
| mm/madvise.c:318:9: warning: variable 'orig_pte' set but not used
| [-Wunused-but-set-variable]
Rewrite pte_unmap() as a static inline function, which silences the
warnings.
Signed-off-by: Qian Cai <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
Add a new flag VM_FLUSH_RESET_PERMS, for enabling vfree operations to
immediately clear executable TLB entries before freeing pages, and handle
resetting permissions on the directmap. This flag is useful for any kind
of memory with elevated permissions, or where there can be related
permissions changes on the directmap. Today this is RO+X and RO memory.
Although this enables directly vfreeing non-writeable memory now,
non-writable memory cannot be freed in an interrupt because the allocation
itself is used as a node on deferred free list. So when RO memory needs to
be freed in an interrupt the code doing the vfree needs to have its own
work queue, as was the case before the deferred vfree list was added to
vmalloc.
For architectures with set_direct_map_ implementations this whole operation
can be done with one TLB flush when centralized like this. For others with
directmap permissions, currently only arm64, a backup method using
set_memory functions is used to reset the directmap. When arm64 adds
set_direct_map_ functions, this backup can be removed.
When the TLB is flushed to both remove TLB entries for the vmalloc range
mapping and the direct map permissions, the lazy purge operation could be
done to try to save a TLB flush later. However today vm_unmap_aliases
could flush a TLB range that does not include the directmap. So a helper
is added with extra parameters that can allow both the vmalloc address and
the direct mapping to be flushed during this operation. The behavior of the
normal vm_unmap_aliases function is unchanged.
Suggested-by: Dave Hansen <[email protected]>
Suggested-by: Andy Lutomirski <[email protected]>
Suggested-by: Will Deacon <[email protected]>
Signed-off-by: Rick Edgecombe <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Nadav Amit <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
When modules and BPF filters are loaded, there is a time window in
which some memory is both writable and executable. An attacker that has
already found another vulnerability (e.g., a dangling pointer) might be
able to exploit this behavior to overwrite kernel code. Prevent having
writable executable PTEs in this stage.
In addition, avoiding having W+X mappings can also slightly simplify the
patching of modules code on initialization (e.g., by alternatives and
static-key), as would be done in the next patch. This was actually the
main motivation for this patch.
To avoid having W+X mappings, set them initially as RW (NX) and after
they are set as RO set them as X as well. Setting them as executable is
done as a separate step to avoid one core in which the old PTE is cached
(hence writable), and another which sees the updated PTE (executable),
which would break the W^X protection.
Suggested-by: Thomas Gleixner <[email protected]>
Suggested-by: Andy Lutomirski <[email protected]>
Signed-off-by: Nadav Amit <[email protected]>
Signed-off-by: Rick Edgecombe <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Rik van Riel <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
