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commit 213f5f8f31f10aa1e83187ae20fb7fa4e626b724 upstream.
Before commit faa041a40b9f ("ipv4: Create cleanup helper for fib_nh")
changes to net->ipv4.fib_num_tclassid_users were protected by RTNL.
After the change, this is no longer the case, as free_fib_info_rcu()
runs after rcu grace period, without rtnl being held.
Fixes: faa041a40b9f ("ipv4: Create cleanup helper for fib_nh")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: David Ahern <dsahern@kernel.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 7a10d8c810cfad3e79372d7d1c77899d86cd6662 upstream.
syzbot found that __dev_queue_xmit() is reading txq->xmit_lock_owner
without annotations.
No serious issue there, let's document what is happening there.
BUG: KCSAN: data-race in __dev_queue_xmit / __dev_queue_xmit
write to 0xffff888139d09484 of 4 bytes by interrupt on cpu 0:
__netif_tx_unlock include/linux/netdevice.h:4437 [inline]
__dev_queue_xmit+0x948/0xf70 net/core/dev.c:4229
dev_queue_xmit_accel+0x19/0x20 net/core/dev.c:4265
macvlan_queue_xmit drivers/net/macvlan.c:543 [inline]
macvlan_start_xmit+0x2b3/0x3d0 drivers/net/macvlan.c:567
__netdev_start_xmit include/linux/netdevice.h:4987 [inline]
netdev_start_xmit include/linux/netdevice.h:5001 [inline]
xmit_one+0x105/0x2f0 net/core/dev.c:3590
dev_hard_start_xmit+0x72/0x120 net/core/dev.c:3606
sch_direct_xmit+0x1b2/0x7c0 net/sched/sch_generic.c:342
__dev_xmit_skb+0x83d/0x1370 net/core/dev.c:3817
__dev_queue_xmit+0x590/0xf70 net/core/dev.c:4194
dev_queue_xmit+0x13/0x20 net/core/dev.c:4259
neigh_hh_output include/net/neighbour.h:511 [inline]
neigh_output include/net/neighbour.h:525 [inline]
ip6_finish_output2+0x995/0xbb0 net/ipv6/ip6_output.c:126
__ip6_finish_output net/ipv6/ip6_output.c:191 [inline]
ip6_finish_output+0x444/0x4c0 net/ipv6/ip6_output.c:201
NF_HOOK_COND include/linux/netfilter.h:296 [inline]
ip6_output+0x10e/0x210 net/ipv6/ip6_output.c:224
dst_output include/net/dst.h:450 [inline]
NF_HOOK include/linux/netfilter.h:307 [inline]
ndisc_send_skb+0x486/0x610 net/ipv6/ndisc.c:508
ndisc_send_rs+0x3b0/0x3e0 net/ipv6/ndisc.c:702
addrconf_rs_timer+0x370/0x540 net/ipv6/addrconf.c:3898
call_timer_fn+0x2e/0x240 kernel/time/timer.c:1421
expire_timers+0x116/0x240 kernel/time/timer.c:1466
__run_timers+0x368/0x410 kernel/time/timer.c:1734
run_timer_softirq+0x2e/0x60 kernel/time/timer.c:1747
__do_softirq+0x158/0x2de kernel/softirq.c:558
__irq_exit_rcu kernel/softirq.c:636 [inline]
irq_exit_rcu+0x37/0x70 kernel/softirq.c:648
sysvec_apic_timer_interrupt+0x3e/0xb0 arch/x86/kernel/apic/apic.c:1097
asm_sysvec_apic_timer_interrupt+0x12/0x20
read to 0xffff888139d09484 of 4 bytes by interrupt on cpu 1:
__dev_queue_xmit+0x5e3/0xf70 net/core/dev.c:4213
dev_queue_xmit_accel+0x19/0x20 net/core/dev.c:4265
macvlan_queue_xmit drivers/net/macvlan.c:543 [inline]
macvlan_start_xmit+0x2b3/0x3d0 drivers/net/macvlan.c:567
__netdev_start_xmit include/linux/netdevice.h:4987 [inline]
netdev_start_xmit include/linux/netdevice.h:5001 [inline]
xmit_one+0x105/0x2f0 net/core/dev.c:3590
dev_hard_start_xmit+0x72/0x120 net/core/dev.c:3606
sch_direct_xmit+0x1b2/0x7c0 net/sched/sch_generic.c:342
__dev_xmit_skb+0x83d/0x1370 net/core/dev.c:3817
__dev_queue_xmit+0x590/0xf70 net/core/dev.c:4194
dev_queue_xmit+0x13/0x20 net/core/dev.c:4259
neigh_resolve_output+0x3db/0x410 net/core/neighbour.c:1523
neigh_output include/net/neighbour.h:527 [inline]
ip6_finish_output2+0x9be/0xbb0 net/ipv6/ip6_output.c:126
__ip6_finish_output net/ipv6/ip6_output.c:191 [inline]
ip6_finish_output+0x444/0x4c0 net/ipv6/ip6_output.c:201
NF_HOOK_COND include/linux/netfilter.h:296 [inline]
ip6_output+0x10e/0x210 net/ipv6/ip6_output.c:224
dst_output include/net/dst.h:450 [inline]
NF_HOOK include/linux/netfilter.h:307 [inline]
ndisc_send_skb+0x486/0x610 net/ipv6/ndisc.c:508
ndisc_send_rs+0x3b0/0x3e0 net/ipv6/ndisc.c:702
addrconf_rs_timer+0x370/0x540 net/ipv6/addrconf.c:3898
call_timer_fn+0x2e/0x240 kernel/time/timer.c:1421
expire_timers+0x116/0x240 kernel/time/timer.c:1466
__run_timers+0x368/0x410 kernel/time/timer.c:1734
run_timer_softirq+0x2e/0x60 kernel/time/timer.c:1747
__do_softirq+0x158/0x2de kernel/softirq.c:558
__irq_exit_rcu kernel/softirq.c:636 [inline]
irq_exit_rcu+0x37/0x70 kernel/softirq.c:648
sysvec_apic_timer_interrupt+0x8d/0xb0 arch/x86/kernel/apic/apic.c:1097
asm_sysvec_apic_timer_interrupt+0x12/0x20
kcsan_setup_watchpoint+0x94/0x420 kernel/kcsan/core.c:443
folio_test_anon include/linux/page-flags.h:581 [inline]
PageAnon include/linux/page-flags.h:586 [inline]
zap_pte_range+0x5ac/0x10e0 mm/memory.c:1347
zap_pmd_range mm/memory.c:1467 [inline]
zap_pud_range mm/memory.c:1496 [inline]
zap_p4d_range mm/memory.c:1517 [inline]
unmap_page_range+0x2dc/0x3d0 mm/memory.c:1538
unmap_single_vma+0x157/0x210 mm/memory.c:1583
unmap_vmas+0xd0/0x180 mm/memory.c:1615
exit_mmap+0x23d/0x470 mm/mmap.c:3170
__mmput+0x27/0x1b0 kernel/fork.c:1113
mmput+0x3d/0x50 kernel/fork.c:1134
exit_mm+0xdb/0x170 kernel/exit.c:507
do_exit+0x608/0x17a0 kernel/exit.c:819
do_group_exit+0xce/0x180 kernel/exit.c:929
get_signal+0xfc3/0x1550 kernel/signal.c:2852
arch_do_signal_or_restart+0x8c/0x2e0 arch/x86/kernel/signal.c:868
handle_signal_work kernel/entry/common.c:148 [inline]
exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
exit_to_user_mode_prepare+0x113/0x190 kernel/entry/common.c:207
__syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
do_syscall_64+0x50/0xd0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x44/0xae
value changed: 0x00000000 -> 0xffffffff
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 28712 Comm: syz-executor.0 Tainted: G W 5.16.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Link: https://lore.kernel.org/r/20211130170155.2331929-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit f7e5b9bfa6c8820407b64eabc1f29c9a87e8993d upstream.
On ARM v6 and later, we define CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
because the ordinary load/store instructions (ldr, ldrh, ldrb) can
tolerate any misalignment of the memory address. However, load/store
double and load/store multiple instructions (ldrd, ldm) may still only
be used on memory addresses that are 32-bit aligned, and so we have to
use the CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS macro with care, or we
may end up with a severe performance hit due to alignment traps that
require fixups by the kernel. Testing shows that this currently happens
with clang-13 but not gcc-11. In theory, any compiler version can
produce this bug or other problems, as we are dealing with undefined
behavior in C99 even on architectures that support this in hardware,
see also https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100363.
Fortunately, the get_unaligned() accessors do the right thing: when
building for ARMv6 or later, the compiler will emit unaligned accesses
using the ordinary load/store instructions (but avoid the ones that
require 32-bit alignment). When building for older ARM, those accessors
will emit the appropriate sequence of ldrb/mov/orr instructions. And on
architectures that can truly tolerate any kind of misalignment, the
get_unaligned() accessors resolve to the leXX_to_cpup accessors that
operate on aligned addresses.
Since the compiler will in fact emit ldrd or ldm instructions when
building this code for ARM v6 or later, the solution is to use the
unaligned accessors unconditionally on architectures where this is
known to be fast. The _aligned version of the hash function is
however still needed to get the best performance on architectures
that cannot do any unaligned access in hardware.
This new version avoids the undefined behavior and should produce
the fastest hash on all architectures we support.
Link: https://lore.kernel.org/linux-arm-kernel/20181008211554.5355-4-ard.biesheuvel@linaro.org/
Link: https://lore.kernel.org/linux-crypto/CAK8P3a2KfmmGDbVHULWevB0hv71P2oi2ZCHEAqT=8dQfa0=cqQ@mail.gmail.com/
Reported-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Fixes: 2c956a60778c ("siphash: add cryptographically secure PRF")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit dacb5d8875cc6cd3a553363b4d6f06760fcbe70c upstream.
Steffen reported a TCP stream corruption for HTTP requests
served by the apache web-server using a cifs mount-point
and memory mapping the relevant file.
The root cause is quite similar to the one addressed by
commit 20eb4f29b602 ("net: fix sk_page_frag() recursion from
memory reclaim"). Here the nested access to the task page frag
is caused by a page fault on the (mmapped) user-space memory
buffer coming from the cifs file.
The page fault handler performs an smb transaction on a different
socket, inside the same process context. Since sk->sk_allaction
for such socket does not prevent the usage for the task_frag,
the nested allocation modify "under the hood" the page frag
in use by the outer sendmsg call, corrupting the stream.
The overall relevant stack trace looks like the following:
httpd 78268 [001] 3461630.850950: probe:tcp_sendmsg_locked:
ffffffff91461d91 tcp_sendmsg_locked+0x1
ffffffff91462b57 tcp_sendmsg+0x27
ffffffff9139814e sock_sendmsg+0x3e
ffffffffc06dfe1d smb_send_kvec+0x28
[...]
ffffffffc06cfaf8 cifs_readpages+0x213
ffffffff90e83c4b read_pages+0x6b
ffffffff90e83f31 __do_page_cache_readahead+0x1c1
ffffffff90e79e98 filemap_fault+0x788
ffffffff90eb0458 __do_fault+0x38
ffffffff90eb5280 do_fault+0x1a0
ffffffff90eb7c84 __handle_mm_fault+0x4d4
ffffffff90eb8093 handle_mm_fault+0xc3
ffffffff90c74f6d __do_page_fault+0x1ed
ffffffff90c75277 do_page_fault+0x37
ffffffff9160111e page_fault+0x1e
ffffffff9109e7b5 copyin+0x25
ffffffff9109eb40 _copy_from_iter_full+0xe0
ffffffff91462370 tcp_sendmsg_locked+0x5e0
ffffffff91462370 tcp_sendmsg_locked+0x5e0
ffffffff91462b57 tcp_sendmsg+0x27
ffffffff9139815c sock_sendmsg+0x4c
ffffffff913981f7 sock_write_iter+0x97
ffffffff90f2cc56 do_iter_readv_writev+0x156
ffffffff90f2dff0 do_iter_write+0x80
ffffffff90f2e1c3 vfs_writev+0xa3
ffffffff90f2e27c do_writev+0x5c
ffffffff90c042bb do_syscall_64+0x5b
ffffffff916000ad entry_SYSCALL_64_after_hwframe+0x65
The cifs filesystem rightfully sets sk_allocations to GFP_NOFS,
we can avoid the nesting using the sk page frag for allocation
lacking the __GFP_FS flag. Do not define an additional mm-helper
for that, as this is strictly tied to the sk page frag usage.
v1 -> v2:
- use a stricted sk_page_frag() check instead of reordering the
code (Eric)
Reported-by: Steffen Froemer <sfroemer@redhat.com>
Fixes: 5640f7685831 ("net: use a per task frag allocator")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 20ae1d6aa159eb91a9bf09ff92ccaa94dbea92c2 upstream.
Each peer's endpoint contains a dst_cache entry that takes a reference
to another netdev. When the containing namespace exits, we take down the
socket and prevent future sockets from being created (by setting
creating_net to NULL), which removes that potential reference on the
netns. However, it doesn't release references to the netns that a netdev
cached in dst_cache might be taking, so the netns still might fail to
exit. Since the socket is gimped anyway, we can simply clear all the
dst_caches (by way of clearing the endpoint src), which will release all
references.
However, the current dst_cache_reset function only releases those
references lazily. But it turns out that all of our usages of
wg_socket_clear_peer_endpoint_src are called from contexts that are not
exactly high-speed or bottle-necked. For example, when there's
connection difficulty, or when userspace is reconfiguring the interface.
And in particular for this patch, when the netns is exiting. So for
those cases, it makes more sense to call dst_release immediately. For
that, we add a small helper function to dst_cache.
This patch also adds a test to netns.sh from Hangbin Liu to ensure this
doesn't regress.
Tested-by: Hangbin Liu <liuhangbin@gmail.com>
Reported-by: Xiumei Mu <xmu@redhat.com>
Cc: Toke Høiland-Jørgensen <toke@redhat.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Fixes: 900575aa33a3 ("wireguard: device: avoid circular netns references")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit cdef485217d30382f3bf6448c54b4401648fe3f1 upstream.
The kernel leaks memory when a `fib` rule is present in IPv6 nftables
firewall rules and a suppress_prefix rule is present in the IPv6 routing
rules (used by certain tools such as wg-quick). In such scenarios, every
incoming packet will leak an allocation in `ip6_dst_cache` slab cache.
After some hours of `bpftrace`-ing and source code reading, I tracked
down the issue to ca7a03c41753 ("ipv6: do not free rt if
FIB_LOOKUP_NOREF is set on suppress rule").
The problem with that change is that the generic `args->flags` always have
`FIB_LOOKUP_NOREF` set[1][2] but the IPv6-specific flag
`RT6_LOOKUP_F_DST_NOREF` might not be, leading to `fib6_rule_suppress` not
decreasing the refcount when needed.
How to reproduce:
- Add the following nftables rule to a prerouting chain:
meta nfproto ipv6 fib saddr . mark . iif oif missing drop
This can be done with:
sudo nft create table inet test
sudo nft create chain inet test test_chain '{ type filter hook prerouting priority filter + 10; policy accept; }'
sudo nft add rule inet test test_chain meta nfproto ipv6 fib saddr . mark . iif oif missing drop
- Run:
sudo ip -6 rule add table main suppress_prefixlength 0
- Watch `sudo slabtop -o | grep ip6_dst_cache` to see memory usage increase
with every incoming ipv6 packet.
This patch exposes the protocol-specific flags to the protocol
specific `suppress` function, and check the protocol-specific `flags`
argument for RT6_LOOKUP_F_DST_NOREF instead of the generic
FIB_LOOKUP_NOREF when decreasing the refcount, like this.
[1]: https://github.com/torvalds/linux/blob/ca7a03c4175366a92cee0ccc4fec0038c3266e26/net/ipv6/fib6_rules.c#L71
[2]: https://github.com/torvalds/linux/blob/ca7a03c4175366a92cee0ccc4fec0038c3266e26/net/ipv6/fib6_rules.c#L99
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215105
Fixes: ca7a03c41753 ("ipv6: do not free rt if FIB_LOOKUP_NOREF is set on suppress rule")
Cc: stable@vger.kernel.org
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 6bbfa44116689469267f1a6e3d233b52114139d2 upstream.
The 'kprobe::data_size' is unsigned, thus it can not be negative. But if
user sets it enough big number (e.g. (size_t)-8), the result of 'data_size
+ sizeof(struct kretprobe_instance)' becomes smaller than sizeof(struct
kretprobe_instance) or zero. In result, the kretprobe_instance are
allocated without enough memory, and kretprobe accesses outside of
allocated memory.
To avoid this issue, introduce a max limitation of the
kretprobe::data_size. 4KB per instance should be OK.
Link: https://lkml.kernel.org/r/163836995040.432120.10322772773821182925.stgit@devnote2
Cc: stable@vger.kernel.org
Fixes: f47cd9b553aa ("kprobes: kretprobe user entry-handler")
Reported-by: zhangyue <zhangyue1@kylinos.cn>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit e9380df851878cee71df5a1c7611584421527f7e ]
The commit ddfd9dcf270c ("ACPI: PM: Add acpi_[un]register_wakeup_handler()")
added new functions for drivers to use during the s2idle wakeup path, but
didn't add stubs for when CONFIG_ACPI wasn't set.
Add those stubs in for other drivers to be able to use.
Fixes: ddfd9dcf270c ("ACPI: PM: Add acpi_[un]register_wakeup_handler()")
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20211101014853.6177-1-mario.limonciello@amd.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 85b6d24646e4125c591639841169baa98a2da503 upstream.
Currently, the exit_shm() function not designed to work properly when
task->sysvshm.shm_clist holds shm objects from different IPC namespaces.
This is a real pain when sysctl kernel.shm_rmid_forced = 1, because it
leads to use-after-free (reproducer exists).
This is an attempt to fix the problem by extending exit_shm mechanism to
handle shm's destroy from several IPC ns'es.
To achieve that we do several things:
1. add a namespace (non-refcounted) pointer to the struct shmid_kernel
2. during new shm object creation (newseg()/shmget syscall) we
initialize this pointer by current task IPC ns
3. exit_shm() fully reworked such that it traverses over all shp's in
task->sysvshm.shm_clist and gets IPC namespace not from current task
as it was before but from shp's object itself, then call
shm_destroy(shp, ns).
Note: We need to be really careful here, because as it was said before
(1), our pointer to IPC ns non-refcnt'ed. To be on the safe side we
using special helper get_ipc_ns_not_zero() which allows to get IPC ns
refcounter only if IPC ns not in the "state of destruction".
Q/A
Q: Why can we access shp->ns memory using non-refcounted pointer?
A: Because shp object lifetime is always shorther than IPC namespace
lifetime, so, if we get shp object from the task->sysvshm.shm_clist
while holding task_lock(task) nobody can steal our namespace.
Q: Does this patch change semantics of unshare/setns/clone syscalls?
A: No. It's just fixes non-covered case when process may leave IPC
namespace without getting task->sysvshm.shm_clist list cleaned up.
Link: https://lkml.kernel.org/r/67bb03e5-f79c-1815-e2bf-949c67047418@colorfullife.com
Link: https://lkml.kernel.org/r/20211109151501.4921-1-manfred@colorfullife.com
Fixes: ab602f79915 ("shm: make exit_shm work proportional to task activity")
Co-developed-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Cc: Vasily Averin <vvs@virtuozzo.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 629a5d87e26fe96bcaab44cbb81f5866af6f7008 upstream.
Sync include/xen/interface/io/ring.h with Xen's newest version in
order to get the RING_COPY_RESPONSE() and RING_RESPONSE_PROD_OVERFLOW()
macros.
Note that this will correct the wrong license info by adding the
missing original copyright notice.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 8837cbbf854246f5f4d565f21e6baa945d37aded ]
We need a way to release a fib6_nh's per-cpu dsts when replacing
nexthops otherwise we can end up with stale per-cpu dsts which hold net
device references, so add a new IPv6 stub called fib6_nh_release_dsts.
It must be used after an RCU grace period, so no new dsts can be created
through a group's nexthop entry.
Similar to fib6_nh_release it shouldn't be used if fib6_nh_init has failed
so it doesn't need a dummy stub when IPv6 is not enabled.
Fixes: 7bf4796dd099 ("nexthops: add support for replace")
Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 451dc48c806a7ce9fbec5e7a24ccf4b2c936e834 ]
This patch fixes an issue that an u32 netlink value is handled as a
signed enum value which doesn't fit into the range of u32 netlink type.
If it's handled as -1 value some BIT() evaluation ends in a
shift-out-of-bounds issue. To solve the issue we set the to u32 max which
is s32 "-1" value to keep backwards compatibility and let the followed enum
values start counting at 0. This brings the compiler to never handle the
enum as signed and a check if the value is above NL802154_IFTYPE_MAX should
filter -1 out.
Fixes: f3ea5e44231a ("ieee802154: add new interface command")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/r/20211112030916.685793-1-aahringo@redhat.com
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 353050be4c19e102178ccc05988101887c25ae53 upstream.
Commit a23740ec43ba ("bpf: Track contents of read-only maps as scalars") is
checking whether maps are read-only both from BPF program side and user space
side, and then, given their content is constant, reading out their data via
map->ops->map_direct_value_addr() which is then subsequently used as known
scalar value for the register, that is, it is marked as __mark_reg_known()
with the read value at verification time. Before a23740ec43ba, the register
content was marked as an unknown scalar so the verifier could not make any
assumptions about the map content.
The current implementation however is prone to a TOCTOU race, meaning, the
value read as known scalar for the register is not guaranteed to be exactly
the same at a later point when the program is executed, and as such, the
prior made assumptions of the verifier with regards to the program will be
invalid which can cause issues such as OOB access, etc.
While the BPF_F_RDONLY_PROG map flag is always fixed and required to be
specified at map creation time, the map->frozen property is initially set to
false for the map given the map value needs to be populated, e.g. for global
data sections. Once complete, the loader "freezes" the map from user space
such that no subsequent updates/deletes are possible anymore. For the rest
of the lifetime of the map, this freeze one-time trigger cannot be undone
anymore after a successful BPF_MAP_FREEZE cmd return. Meaning, any new BPF_*
cmd calls which would update/delete map entries will be rejected with -EPERM
since map_get_sys_perms() removes the FMODE_CAN_WRITE permission. This also
means that pending update/delete map entries must still complete before this
guarantee is given. This corner case is not an issue for loaders since they
create and prepare such program private map in successive steps.
However, a malicious user is able to trigger this TOCTOU race in two different
ways: i) via userfaultfd, and ii) via batched updates. For i) userfaultfd is
used to expand the competition interval, so that map_update_elem() can modify
the contents of the map after map_freeze() and bpf_prog_load() were executed.
This works, because userfaultfd halts the parallel thread which triggered a
map_update_elem() at the time where we copy key/value from the user buffer and
this already passed the FMODE_CAN_WRITE capability test given at that time the
map was not "frozen". Then, the main thread performs the map_freeze() and
bpf_prog_load(), and once that had completed successfully, the other thread
is woken up to complete the pending map_update_elem() which then changes the
map content. For ii) the idea of the batched update is similar, meaning, when
there are a large number of updates to be processed, it can increase the
competition interval between the two. It is therefore possible in practice to
modify the contents of the map after executing map_freeze() and bpf_prog_load().
One way to fix both i) and ii) at the same time is to expand the use of the
map's map->writecnt. The latter was introduced in fc9702273e2e ("bpf: Add mmap()
support for BPF_MAP_TYPE_ARRAY") and further refined in 1f6cb19be2e2 ("bpf:
Prevent re-mmap()'ing BPF map as writable for initially r/o mapping") with
the rationale to make a writable mmap()'ing of a map mutually exclusive with
read-only freezing. The counter indicates writable mmap() mappings and then
prevents/fails the freeze operation. Its semantics can be expanded beyond
just mmap() by generally indicating ongoing write phases. This would essentially
span any parallel regular and batched flavor of update/delete operation and
then also have map_freeze() fail with -EBUSY. For the check_mem_access() in
the verifier we expand upon the bpf_map_is_rdonly() check ensuring that all
last pending writes have completed via bpf_map_write_active() test. Once the
map->frozen is set and bpf_map_write_active() indicates a map->writecnt of 0
only then we are really guaranteed to use the map's data as known constants.
For map->frozen being set and pending writes in process of still being completed
we fall back to marking that register as unknown scalar so we don't end up
making assumptions about it. With this, both TOCTOU reproducers from i) and
ii) are fixed.
Note that the map->writecnt has been converted into a atomic64 in the fix in
order to avoid a double freeze_mutex mutex_{un,}lock() pair when updating
map->writecnt in the various map update/delete BPF_* cmd flavors. Spanning
the freeze_mutex over entire map update/delete operations in syscall side
would not be possible due to then causing everything to be serialized.
Similarly, something like synchronize_rcu() after setting map->frozen to wait
for update/deletes to complete is not possible either since it would also
have to span the user copy which can sleep. On the libbpf side, this won't
break d66562fba1ce ("libbpf: Add BPF object skeleton support") as the
anonymous mmap()-ed "map initialization image" is remapped as a BPF map-backed
mmap()-ed memory where for .rodata it's non-writable.
Fixes: a23740ec43ba ("bpf: Track contents of read-only maps as scalars")
Reported-by: w1tcher.bupt@gmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
[fix conflict to call bpf_map_write_active_dec() in err_put block.
fix conflict to insert new functions after find_and_alloc_map().]
Reference: CVE-2021-4001
Signed-off-by: Masami Ichikawa(CIP) <masami.ichikawa@cybertrust.co.jp>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This reverts commit 94902ee2996a7f71471138093495df452dab87b6 which is
upstream commit ef54c1a476aef7eef26fe13ea10dc090952c00f8.
Reverting for now due to issues that need to get fixed upstream.
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 868ddfcef31ff93ea8961b2e81ea7fe12f6f144b upstream.
The code for hdac_ext_stream seems inherited from hdac_stream, and
similar locking issues are present: the use of the bus->reg_lock
spinlock is inconsistent, with only writes to specific fields being
protected.
Apply similar fix as in hdac_stream by protecting all accesses to
'link_locked' and 'decoupled' fields, with a new helper
snd_hdac_ext_stream_decouple_locked() added to simplify code
changes.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210924192417.169243-4-pierre-louis.bossart@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e60feb445fce9e51c1558a6aa7faf9dd5ded533b upstream.
If you already have an inode and need to update the time on the inode
there is no way to do this properly. Export this helper to allow file
systems to update time on the inode so the appropriate handler is
called, either ->update_time or generic_update_time.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 83dde7498fefeb920b1def317421262317d178e5 upstream.
Like other commits in the tree add __maybe_unused to a static inline in a
C file because some clang compilers will complain about unused code:
>> drivers/infiniband/core/nldev.c:2543:1: warning: unused function '__chk_RDMA_NL_NLDEV'
MODULE_ALIAS_RDMA_NETLINK(RDMA_NL_NLDEV, 5);
^
Fixes: e3bf14bdc17a ("rdma: Autoload netlink client modules")
Link: https://lore.kernel.org/r/4a8101919b765e01d7fde6f27fd572c958deeb4a.1636267207.git.leonro@nvidia.com
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 48b71a9e66c2eab60564b1b1c85f4928ed04e406 ]
There are two sites that calls queue_work() after the
destroy_workqueue() and lead to possible UAF.
The first site is nci_send_cmd(), which can happen after the
nci_close_device as below
nfcmrvl_nci_unregister_dev | nfc_genl_dev_up
nci_close_device |
flush_workqueue |
del_timer_sync |
nci_unregister_device | nfc_get_device
destroy_workqueue | nfc_dev_up
nfc_unregister_device | nci_dev_up
device_del | nci_open_device
| __nci_request
| nci_send_cmd
| queue_work !!!
Another site is nci_cmd_timer, awaked by the nci_cmd_work from the
nci_send_cmd.
... | ...
nci_unregister_device | queue_work
destroy_workqueue |
nfc_unregister_device | ...
device_del | nci_cmd_work
| mod_timer
| ...
| nci_cmd_timer
| queue_work !!!
For the above two UAF, the root cause is that the nfc_dev_up can race
between the nci_unregister_device routine. Therefore, this patch
introduce NCI_UNREG flag to easily eliminate the possible race. In
addition, the mutex_lock in nci_close_device can act as a barrier.
Signed-off-by: Lin Ma <linma@zju.edu.cn>
Fixes: 6a2968aaf50c ("NFC: basic NCI protocol implementation")
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20211116152732.19238-1-linma@zju.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit cf9acc90c80ecbee00334aa85d92f4e74014bcff ]
virtio_net_hdr_to_skb does not set the skb's gso_size and gso_type
correctly for UFO packets received via virtio-net that are a little over
the GSO size. This can lead to problems elsewhere in the networking
stack, e.g. ovs_vport_send dropping over-sized packets if gso_size is
not set.
This is due to the comparison
if (skb->len - p_off > gso_size)
not properly accounting for the transport layer header.
p_off includes the size of the transport layer header (thlen), so
skb->len - p_off is the size of the TCP/UDP payload.
gso_size is read from the virtio-net header. For UFO, fragmentation
happens at the IP level so does not need to include the UDP header.
Hence the calculation could be comparing a TCP/UDP payload length with
an IP payload length, causing legitimate virtio-net packets to have
lack gso_type/gso_size information.
Example: a UDP packet with payload size 1473 has IP payload size 1481.
If the guest used UFO, it is not fragmented and the virtio-net header's
flags indicate that it is a GSO frame (VIRTIO_NET_HDR_GSO_UDP), with
gso_size = 1480 for an MTU of 1500. skb->len will be 1515 and p_off
will be 42, so skb->len - p_off = 1473. Hence the comparison fails, and
shinfo->gso_size and gso_type are not set as they should be.
Instead, add the UDP header length before comparing to gso_size when
using UFO. In this way, it is the size of the IP payload that is
compared to gso_size.
Fixes: 6dd912f82680 ("net: check untrusted gso_size at kernel entry")
Signed-off-by: Jonathan Davies <jonathan.davies@nutanix.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 938aa33f14657c9ed9deea348b7d6f14b6d69cb7 ]
The string copies to the histogram storage has a max size of 256 bytes
(defined by MAX_FILTER_STR_VAL). Only the string size of the event field
needs to be copied to the event storage, but no more than what is in the
event storage. Although nothing should be bigger than 256 bytes, there's
no protection against overwriting of the storage if one day there is.
Copy no more than the destination size, and enforce it.
Also had to turn MAX_FILTER_STR_VAL into an unsigned int, to keep the
min() comparison of the string sizes of comparable types.
Link: https://lore.kernel.org/all/CAHk-=wjREUihCGrtRBwfX47y_KrLCGjiq3t6QtoNJpmVrAEb1w@mail.gmail.com/
Link: https://lkml.kernel.org/r/20211114132834.183429a4@rorschach.local.home
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: 63f84ae6b82b ("tracing/histogram: Do not copy the fixed-size char array field over the field size")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 18fb76ed53865c1b5d5f0157b1b825704590beb5 ]
When TCP receive zerocopy does not successfully map the entire
requested space, it outputs a 'hint' that the caller should recvmsg().
Augment zerocopy to accept a user buffer that it tries to copy this
hint into - if it is possible to copy the entire hint, it will do so.
This elides a recvmsg() call for received traffic that isn't exactly
page-aligned in size.
This was tested with RPC-style traffic of arbitrary sizes. Normally,
each received message required at least one getsockopt() call, and one
recvmsg() call for the remaining unaligned data.
With this change, almost all of the recvmsg() calls are eliminated,
leading to a savings of about 25%-50% in number of system calls
for RPC-style workloads.
Signed-off-by: Arjun Roy <arjunroy@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 70a9ac36ffd807ac506ed0b849f3e8ce3c6623f2 ]
Fix up a misuse that the filename pointer isn't always valid in
the ring buffer, and we should copy the content instead.
Fixes: 0c5e36db17f5 ("f2fs: trace f2fs_lookup")
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit ed1227e080990ffec5bf39006ec8a57358e6689a ]
This patch fixes the following bugs:
1. If there are multiple ordered cmds queued and multiple simple cmds
completing, target_restart_delayed_cmds() could be called on different
CPUs and each instance could start a ordered cmd. They could then run in
different orders than they were queued.
2. target_restart_delayed_cmds() and target_handle_task_attr() can race
where:
1. target_handle_task_attr() has passed the simple_cmds == 0 check.
2. transport_complete_task_attr() then decrements simple_cmds to 0.
3. transport_complete_task_attr() runs target_restart_delayed_cmds() and
it does not see any cmds on the delayed_cmd_list.
4. target_handle_task_attr() adds the cmd to the delayed_cmd_list.
The cmd will then end up timing out.
3. If we are sent > 1 ordered cmds and simple_cmds == 0, we can execute
them out of order, because target_handle_task_attr() will hit that
simple_cmds check first and return false for all ordered cmds sent.
4. We run target_restart_delayed_cmds() after every cmd completion, so if
there is more than 1 simple cmd running, we start executing ordered cmds
after that first cmd instead of waiting for all of them to complete.
5. Ordered cmds are not supposed to start until HEAD OF QUEUE and all older
cmds have completed, and not just simple.
6. It's not a bug but it doesn't make sense to take the delayed_cmd_lock
for every cmd completion when ordered cmds are almost never used. Just
replacing that lock with an atomic increases IOPs by up to 10% when
completions are spread over multiple CPUs and there are multiple
sessions/ mqs/thread accessing the same device.
This patch moves the queued delayed handling to a per device work to
serialze the cmd executions for each device and adds a new counter to track
HEAD_OF_QUEUE and SIMPLE cmds. We can then check the new counter to
determine when to run the work on the completion path.
Link: https://lore.kernel.org/r/20210930020422.92578-3-michael.christie@oracle.com
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 9d881361206ebcf6285c2ec2ef275aff80875347 ]
Some interconnect target modules such as otg and gpmc on am335x need a
re-init after resume. As we also have PM runtime cases where the context
may be lost, let's handle these all with cpu_pm.
For the am335x resume path, we already have cpu_pm_resume() call
cpu_pm_cluster_exit().
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 2226667a145db2e1f314d7f57fd644fe69863ab9 upstream.
It appears that some devices are lying about their mask capability,
pretending that they don't have it, while they actually do.
The net result is that now that we don't enable MSIs on such
endpoint.
Add a new per-device flag to deal with this. Further patches will
make use of it, sadly.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20211104180130.3825416-2-maz@kernel.org
Cc: Bjorn Helgaas <helgaas@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 570b1cac477643cbf01a45fa5d018430a1fddbce upstream.
There are some duplicated codes to validate the block
size in block drivers. This limitation actually comes
from block layer, so this patch tries to add a new block
layer helper for that.
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Link: https://lore.kernel.org/r/20211026144015.188-2-xieyongji@bytedance.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Tadeusz Struk <tadeusz.struk@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 46b49b12f3fc5e1347dba37d4639e2165f447871 upstream.
In preparation for other confidential computing technologies, introduce
a generic helper function, cc_platform_has(), that can be used to
check for specific active confidential computing attributes, like
memory encryption. This is intended to eliminate having to add multiple
technology-specific checks to the code (e.g. if (sev_active() ||
tdx_active() || ... ).
[ bp: s/_CC_PLATFORM_H/_LINUX_CC_PLATFORM_H/g ]
Co-developed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Co-developed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210928191009.32551-3-bp@alien8.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 460275f124fb072dca218a6b43b6370eebbab20d upstream.
Define a macro PCI_EXP_DEVCTL_PAYLOAD_* for every possible Max Payload
Size in linux/pci_regs.h, in the same style as PCI_EXP_DEVCTL_READRQ_*.
Link: https://lore.kernel.org/r/20211005180952.6812-2-kabel@kernel.org
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 3dc20f4762c62d3b3f0940644881ed818aa7b2f5 ]
Currently, it is not possible to migrate a neighbor entry between NUD_PERMANENT
state and NTF_USE flag with a dynamic NUD state from a user space control plane.
Similarly, it is not possible to add/remove NTF_EXT_LEARNED flag from an existing
neighbor entry in combination with NTF_USE flag.
This is due to the latter directly calling into neigh_event_send() without any
meta data updates as happening in __neigh_update(). Thus, to enable this use
case, extend the latter with a NEIGH_UPDATE_F_USE flag where we break the
NUD_PERMANENT state in particular so that a latter neigh_event_send() is able
to re-resolve a neighbor entry.
Before fix, NUD_PERMANENT -> NUD_* & NTF_USE:
# ./ip/ip n replace 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a PERMANENT
[...]
# ./ip/ip n replace 192.168.178.30 dev enp5s0 use extern_learn
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a PERMANENT
[...]
As can be seen, despite the admin-triggered replace, the entry remains in the
NUD_PERMANENT state.
After fix, NUD_PERMANENT -> NUD_* & NTF_USE:
# ./ip/ip n replace 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a PERMANENT
[...]
# ./ip/ip n replace 192.168.178.30 dev enp5s0 use extern_learn
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a extern_learn REACHABLE
[...]
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a extern_learn STALE
[...]
# ./ip/ip n replace 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a PERMANENT
[...]
After the fix, the admin-triggered replace switches to a dynamic state from
the NTF_USE flag which triggered a new neighbor resolution. Likewise, we can
transition back from there, if needed, into NUD_PERMANENT.
Similar before/after behavior can be observed for below transitions:
Before fix, NTF_USE -> NTF_USE | NTF_EXT_LEARNED -> NTF_USE:
# ./ip/ip n replace 192.168.178.30 dev enp5s0 use
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a REACHABLE
[...]
# ./ip/ip n replace 192.168.178.30 dev enp5s0 use extern_learn
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a REACHABLE
[...]
After fix, NTF_USE -> NTF_USE | NTF_EXT_LEARNED -> NTF_USE:
# ./ip/ip n replace 192.168.178.30 dev enp5s0 use
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a REACHABLE
[...]
# ./ip/ip n replace 192.168.178.30 dev enp5s0 use extern_learn
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a extern_learn REACHABLE
[...]
# ./ip/ip n replace 192.168.178.30 dev enp5s0 use
# ./ip/ip n
192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a REACHABLE
[..]
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Roopa Prabhu <roopa@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit ca7752caeaa70bd31d1714af566c9809688544af upstream.
copy_process currently copies task_struct.posix_cputimers_work as-is. If a
timer interrupt arrives while handling clone and before dup_task_struct
completes then the child task will have:
1. posix_cputimers_work.scheduled = true
2. posix_cputimers_work.work queued.
copy_process clears task_struct.task_works, so (2) will have no effect and
posix_cpu_timers_work will never run (not to mention it doesn't make sense
for two tasks to share a common linked list).
Since posix_cpu_timers_work never runs, posix_cputimers_work.scheduled is
never cleared. Since scheduled is set, future timer interrupts will skip
scheduling work, with the ultimate result that the task will never receive
timer expirations.
Together, the complete flow is:
1. Task 1 calls clone(), enters kernel.
2. Timer interrupt fires, schedules task work on Task 1.
2a. task_struct.posix_cputimers_work.scheduled = true
2b. task_struct.posix_cputimers_work.work added to
task_struct.task_works.
3. dup_task_struct() copies Task 1 to Task 2.
4. copy_process() clears task_struct.task_works for Task 2.
5. Future timer interrupts on Task 2 see
task_struct.posix_cputimers_work.scheduled = true and skip scheduling
work.
Fix this by explicitly clearing contents of task_struct.posix_cputimers_work
in copy_process(). This was never meant to be shared or inherited across
tasks in the first place.
Fixes: 1fb497dd0030 ("posix-cpu-timers: Provide mechanisms to defer timer handling to task_work")
Reported-by: Rhys Hiltner <rhys@justin.tv>
Signed-off-by: Michael Pratt <mpratt@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20211101210615.716522-1-mpratt@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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