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since UNKNOWN_VALUE type is weaker than CONST_IMM we can un-teach
verifier its recognition of constants in conditional branches
without affecting safety.
Ex:
if (reg == 123) {
.. here verifier was marking reg->type as CONST_IMM
instead keep reg as UNKNOWN_VALUE
}
Two verifier states with UNKNOWN_VALUE are equivalent, whereas
CONST_IMM_X != CONST_IMM_Y, since CONST_IMM is used for stack range
verification and other cases.
So help search pruning by marking registers as UNKNOWN_VALUE
where possible instead of CONST_IMM.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Extended BPF carried over two instructions from classic to access
packet data: LD_ABS and LD_IND. They're highly optimized in JITs,
but due to their design they have to do length check for every access.
When BPF is processing 20M packets per second single LD_ABS after JIT
is consuming 3% cpu. Hence the need to optimize it further by amortizing
the cost of 'off < skb_headlen' over multiple packet accesses.
One option is to introduce two new eBPF instructions LD_ABS_DW and LD_IND_DW
with similar usage as skb_header_pointer().
The kernel part for interpreter and x64 JIT was implemented in [1], but such
new insns behave like old ld_abs and abort the program with 'return 0' if
access is beyond linear data. Such hidden control flow is hard to workaround
plus changing JITs and rolling out new llvm is incovenient.
Therefore allow cls_bpf/act_bpf program access skb->data directly:
int bpf_prog(struct __sk_buff *skb)
{
struct iphdr *ip;
if (skb->data + sizeof(struct iphdr) + ETH_HLEN > skb->data_end)
/* packet too small */
return 0;
ip = skb->data + ETH_HLEN;
/* access IP header fields with direct loads */
if (ip->version != 4 || ip->saddr == 0x7f000001)
return 1;
[...]
}
This solution avoids introduction of new instructions. llvm stays
the same and all JITs stay the same, but verifier has to work extra hard
to prove safety of the above program.
For XDP the direct store instructions can be allowed as well.
The skb->data is NET_IP_ALIGNED, so for common cases the verifier can check
the alignment. The complex packet parsers where packet pointer is adjusted
incrementally cannot be tracked for alignment, so allow byte access in such cases
and misaligned access on architectures that define efficient_unaligned_access
[1] https://git.kernel.org/cgit/linux/kernel/git/ast/bpf.git/?h=ld_abs_dw
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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cleanup verifier code and prepare it for addition of "pointer to packet" logic
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Conflicts:
net/ipv4/ip_gre.c
Minor conflicts between tunnel bug fixes in net and
ipv6 tunnel cleanups in net-next.
Signed-off-by: David S. Miller <davem@davemloft.net>
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Pull networking fixes from David Miller:
1) MODULE_FIRMWARE firmware string not correct for iwlwifi 8000 chips,
from Sara Sharon.
2) Fix SKB size checks in batman-adv stack on receive, from Sven
Eckelmann.
3) Leak fix on mac80211 interface add error paths, from Johannes Berg.
4) Cannot invoke napi_disable() with BH disabled in myri10ge driver,
fix from Stanislaw Gruszka.
5) Fix sign extension problem when computing feature masks in
net_gso_ok(), from Marcelo Ricardo Leitner.
6) lan78xx driver doesn't count packets and packet lengths in its
statistics properly, fix from Woojung Huh.
7) Fix the buffer allocation sizes in pegasus USB driver, from Petko
Manolov.
8) Fix refcount overflows in bpf, from Alexei Starovoitov.
9) Unified dst cache handling introduced a preempt warning in
ip_tunnel, fix by resetting rather then setting the cached route.
From Paolo Abeni.
10) Listener hash collision test fix in soreuseport, from Craig Gallak
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (47 commits)
gre: do not pull header in ICMP error processing
net: Implement net_dbg_ratelimited() for CONFIG_DYNAMIC_DEBUG case
tipc: only process unicast on intended node
cxgb3: fix out of bounds read
net/smscx5xx: use the device tree for mac address
soreuseport: Fix TCP listener hash collision
net: l2tp: fix reversed udp6 checksum flags
ip_tunnel: fix preempt warning in ip tunnel creation/updating
samples/bpf: fix trace_output example
bpf: fix check_map_func_compatibility logic
bpf: fix refcnt overflow
drivers: net: cpsw: use of_phy_connect() in fixed-link case
dt: cpsw: phy-handle, phy_id, and fixed-link are mutually exclusive
drivers: net: cpsw: don't ignore phy-mode if phy-handle is used
drivers: net: cpsw: fix segfault in case of bad phy-handle
drivers: net: cpsw: fix parsing of phy-handle DT property in dual_emac config
MAINTAINERS: net: Change maintainer for GRETH 10/100/1G Ethernet MAC device driver
gre: reject GUE and FOU in collect metadata mode
pegasus: fixes reported packet length
pegasus: fixes URB buffer allocation size;
...
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Merge fixes from Andrew Morton:
"20 fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
Documentation/sysctl/vm.txt: update numa_zonelist_order description
lib/stackdepot.c: allow the stack trace hash to be zero
rapidio: fix potential NULL pointer dereference
mm/memory-failure: fix race with compound page split/merge
ocfs2/dlm: return zero if deref_done message is successfully handled
Ananth has moved
kcov: don't profile branches in kcov
kcov: don't trace the code coverage code
mm: wake kcompactd before kswapd's short sleep
.mailmap: add Frank Rowand
mm/hwpoison: fix wrong num_poisoned_pages accounting
mm: call swap_slot_free_notify() with page lock held
mm: vmscan: reclaim highmem zone if buffer_heads is over limit
numa: fix /proc/<pid>/numa_maps for THP
mm/huge_memory: replace VM_NO_THP VM_BUG_ON with actual VMA check
mailmap: fix Krzysztof Kozlowski's misspelled name
thp: keep huge zero page pinned until tlb flush
mm: exclude HugeTLB pages from THP page_mapped() logic
kexec: export OFFSET(page.compound_head) to find out compound tail page
kexec: update VMCOREINFO for compound_order/dtor
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
"x86 PMU driver fixes plus a core code race fix"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/intel: Fix incorrect lbr_sel_mask value
perf/x86/intel/pt: Don't die on VMXON
perf/core: Fix perf_event_open() vs. execve() race
perf/x86/amd: Set the size of event map array to PERF_COUNT_HW_MAX
perf/core: Make sysctl_perf_cpu_time_max_percent conform to documentation
perf/x86/intel/rapl: Add missing Haswell model
perf/x86/intel: Add model number for Skylake Server to perf
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Ingo Molnar:
"Two lockdep fixes"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
lockdep: Fix lock_chain::base size
locking/lockdep: Fix ->irq_context calculation
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Profiling 'if' statements in __sanitizer_cov_trace_pc() leads to
unbound recursion and crash:
__sanitizer_cov_trace_pc() ->
ftrace_likely_update ->
__sanitizer_cov_trace_pc() ...
Define DISABLE_BRANCH_PROFILING to disable this tracer.
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Kcov causes the compiler to add a call to __sanitizer_cov_trace_pc() in
every basic block. Ftrace patches in a call to _mcount() to each
function it has annotated.
Letting these mechanisms annotate each other is a bad thing. Break the
loop by adding 'notrace' to __sanitizer_cov_trace_pc() so that ftrace
won't try to patch this code.
This patch lets arm64 with KCOV and STACK_TRACER boot.
Signed-off-by: James Morse <james.morse@arm.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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PageAnon() always look at head page to check PAGE_MAPPING_ANON and tail
page's page->mapping has just a poisoned data since commit 1c290f642101
("mm: sanitize page->mapping for tail pages").
If makedumpfile checks page->mapping of a compound tail page to
distinguish anonymous page as usual, it must fail in newer kernel. So
it's necessary to export OFFSET(page.compound_head) to avoid checking
compound tail pages.
The problem is that unnecessary hugepages won't be removed from a dump
file in kernels 4.5.x and later. This means that extra disk space would
be consumed. It's a problem, but not critical.
Signed-off-by: Atsushi Kumagai <ats-kumagai@wm.jp.nec.com>
Acked-by: Dave Young <dyoung@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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makedumpfile refers page.lru.next to get the order of compound pages for
page filtering.
However, now the order is stored in page.compound_order, hence
VMCOREINFO should be updated to export the offset of
page.compound_order.
The fact is, page.compound_order was introduced already in kernel 4.0,
but the offset of it was the same as page.lru.next until kernel 4.3, so
this was not actual problem.
The above can be said also for page.lru.prev and page.compound_dtor,
it's necessary to detect hugetlbfs pages. Further, the content was
changed from direct address to the ID which means dtor.
The problem is that unnecessary hugepages won't be removed from a dump
file in kernels 4.4.x and later. This means that extra disk space would
be consumed. It's a problem, but not critical.
Signed-off-by: Atsushi Kumagai <ats-kumagai@wm.jp.nec.com>
Acked-by: Dave Young <dyoung@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The commit 35578d798400 ("bpf: Implement function bpf_perf_event_read() that get the selected hardware PMU conuter")
introduced clever way to check bpf_helper<->map_type compatibility.
Later on commit a43eec304259 ("bpf: introduce bpf_perf_event_output() helper") adjusted
the logic and inadvertently broke it.
Get rid of the clever bool compare and go back to two-way check
from map and from helper perspective.
Fixes: a43eec304259 ("bpf: introduce bpf_perf_event_output() helper")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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On a system with >32Gbyte of phyiscal memory and infinite RLIMIT_MEMLOCK,
the malicious application may overflow 32-bit bpf program refcnt.
It's also possible to overflow map refcnt on 1Tb system.
Impose 32k hard limit which means that the same bpf program or
map cannot be shared by more than 32k processes.
Fixes: 1be7f75d1668 ("bpf: enable non-root eBPF programs")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Jann reported that the ptrace_may_access() check in
find_lively_task_by_vpid() is racy against exec().
Specifically:
perf_event_open() execve()
ptrace_may_access()
commit_creds()
... if (get_dumpable() != SUID_DUMP_USER)
perf_event_exit_task();
perf_install_in_context()
would result in installing a counter across the creds boundary.
Fix this by wrapping lots of perf_event_open() in cred_guard_mutex.
This should be fine as perf_event_exit_task() is already called with
cred_guard_mutex held, so all perf locks already nest inside it.
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Minor overlapping changes in the conflicts.
In the macsec case, the change of the default ID macro
name overlapped with the 64-bit netlink attribute alignment
fixes in net-next.
Signed-off-by: David S. Miller <davem@davemloft.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue fix from Tejun Heo:
"So, it turns out we had a silly bug in the most fundamental part of
workqueue for a very long time. AFAICS, this dates back to pre-git
era and has quite likely been there from the time workqueue was first
introduced.
A work item uses its PENDING bit to synchronize multiple queuers.
Anyone who wins the PENDING bit owns the pending state of the work
item. Whether a queuer wins or loses the race, one thing should be
guaranteed - there will soon be at least one execution of the work
item - where "after" means that the execution instance would be able
to see all the changes that the queuer has made prior to the queueing
attempt.
Unfortunately, we were missing a smp_mb() after clearing PENDING for
execution, so nothing guaranteed visibility of the changes that a
queueing loser has made, which manifested as a reproducible blk-mq
stall.
Lots of kudos to Roman for debugging the problem. The patch for
-stable is the minimal one. For v3.7, Peter is working on a patch to
make the code path slightly more efficient and less fragile"
* 'for-4.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: fix ghost PENDING flag while doing MQ IO
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
"Two patches to fix a deadlock which can be easily triggered if memcg
charge moving is used.
This bug was introduced while converting threadgroup locking to a
global percpu_rwsem and is caused by cgroup controller task migration
path depending on the ability to create new kthreads. cpuset had a
similar issue which was fixed by performing heavy-lifting operations
asynchronous to task migration. The two patches fix the same issue in
memcg in a similar way. The first patch makes the mechanism generic
and the second relocates memcg charge moving outside the migration
path.
Given that we don't want to perform heavy operations while
writelocking threadgroup lock anyway, moving them out of the way is a
desirable solution. One thing to note is that the problem was
difficult to debug because lockdep couldn't figure out the deadlock
condition. Looking into how to improve that"
* 'for-4.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
memcg: relocate charge moving from ->attach to ->post_attach
cgroup, cpuset: replace cpuset_post_attach_flush() with cgroup_subsys->post_attach callback
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Pull networking fixes from David Miller:
1) Handle v4/v6 mixed sockets properly in soreuseport, from Craig
Gallak.
2) Bug fixes for the new macsec facility (missing kmalloc NULL checks,
missing locking around netdev list traversal, etc.) from Sabrina
Dubroca.
3) Fix handling of host routes on ifdown in ipv6, from David Ahern.
4) Fix double-fdput in bpf verifier. From Jann Horn.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (31 commits)
bpf: fix double-fdput in replace_map_fd_with_map_ptr()
net: ipv6: Delete host routes on an ifdown
Revert "ipv6: Revert optional address flusing on ifdown."
net/mlx4_en: fix spurious timestamping callbacks
net: dummy: remove note about being Y by default
cxgbi: fix uninitialized flowi6
ipv6: Revert optional address flusing on ifdown.
ipv4/fib: don't warn when primary address is missing if in_dev is dead
net/mlx5: Add pci shutdown callback
net/mlx5_core: Remove static from local variable
net/mlx5e: Use vport MTU rather than physical port MTU
net/mlx5e: Fix minimum MTU
net/mlx5e: Device's mtu field is u16 and not int
net/mlx5_core: Add ConnectX-5 to list of supported devices
net/mlx5e: Fix MLX5E_100BASE_T define
net/mlx5_core: Fix soft lockup in steering error flow
qlcnic: Update version to 5.3.64
net: stmmac: socfpga: Remove re-registration of reset controller
macsec: fix netlink attribute validation
macsec: add missing macsec prefix in uapi
...
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When bpf(BPF_PROG_LOAD, ...) was invoked with a BPF program whose bytecode
references a non-map file descriptor as a map file descriptor, the error
handling code called fdput() twice instead of once (in __bpf_map_get() and
in replace_map_fd_with_map_ptr()). If the file descriptor table of the
current task is shared, this causes f_count to be decremented too much,
allowing the struct file to be freed while it is still in use
(use-after-free). This can be exploited to gain root privileges by an
unprivileged user.
This bug was introduced in
commit 0246e64d9a5f ("bpf: handle pseudo BPF_LD_IMM64 insn"), but is only
exploitable since
commit 1be7f75d1668 ("bpf: enable non-root eBPF programs") because
previously, CAP_SYS_ADMIN was required to reach the vulnerable code.
(posted publicly according to request by maintainer)
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The bug in a workqueue leads to a stalled IO request in MQ ctx->rq_list
with the following backtrace:
[ 601.347452] INFO: task kworker/u129:5:1636 blocked for more than 120 seconds.
[ 601.347574] Tainted: G O 4.4.5-1-storage+ #6
[ 601.347651] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 601.348142] kworker/u129:5 D ffff880803077988 0 1636 2 0x00000000
[ 601.348519] Workqueue: ibnbd_server_fileio_wq ibnbd_dev_file_submit_io_worker [ibnbd_server]
[ 601.348999] ffff880803077988 ffff88080466b900 ffff8808033f9c80 ffff880803078000
[ 601.349662] ffff880807c95000 7fffffffffffffff ffffffff815b0920 ffff880803077ad0
[ 601.350333] ffff8808030779a0 ffffffff815b01d5 0000000000000000 ffff880803077a38
[ 601.350965] Call Trace:
[ 601.351203] [<ffffffff815b0920>] ? bit_wait+0x60/0x60
[ 601.351444] [<ffffffff815b01d5>] schedule+0x35/0x80
[ 601.351709] [<ffffffff815b2dd2>] schedule_timeout+0x192/0x230
[ 601.351958] [<ffffffff812d43f7>] ? blk_flush_plug_list+0xc7/0x220
[ 601.352208] [<ffffffff810bd737>] ? ktime_get+0x37/0xa0
[ 601.352446] [<ffffffff815b0920>] ? bit_wait+0x60/0x60
[ 601.352688] [<ffffffff815af784>] io_schedule_timeout+0xa4/0x110
[ 601.352951] [<ffffffff815b3a4e>] ? _raw_spin_unlock_irqrestore+0xe/0x10
[ 601.353196] [<ffffffff815b093b>] bit_wait_io+0x1b/0x70
[ 601.353440] [<ffffffff815b056d>] __wait_on_bit+0x5d/0x90
[ 601.353689] [<ffffffff81127bd0>] wait_on_page_bit+0xc0/0xd0
[ 601.353958] [<ffffffff81096db0>] ? autoremove_wake_function+0x40/0x40
[ 601.354200] [<ffffffff81127cc4>] __filemap_fdatawait_range+0xe4/0x140
[ 601.354441] [<ffffffff81127d34>] filemap_fdatawait_range+0x14/0x30
[ 601.354688] [<ffffffff81129a9f>] filemap_write_and_wait_range+0x3f/0x70
[ 601.354932] [<ffffffff811ced3b>] blkdev_fsync+0x1b/0x50
[ 601.355193] [<ffffffff811c82d9>] vfs_fsync_range+0x49/0xa0
[ 601.355432] [<ffffffff811cf45a>] blkdev_write_iter+0xca/0x100
[ 601.355679] [<ffffffff81197b1a>] __vfs_write+0xaa/0xe0
[ 601.355925] [<ffffffff81198379>] vfs_write+0xa9/0x1a0
[ 601.356164] [<ffffffff811c59d8>] kernel_write+0x38/0x50
The underlying device is a null_blk, with default parameters:
queue_mode = MQ
submit_queues = 1
Verification that nullb0 has something inflight:
root@pserver8:~# cat /sys/block/nullb0/inflight
0 1
root@pserver8:~# find /sys/block/nullb0/mq/0/cpu* -name rq_list -print -exec cat {} \;
...
/sys/block/nullb0/mq/0/cpu2/rq_list
CTX pending:
ffff8838038e2400
...
During debug it became clear that stalled request is always inserted in
the rq_list from the following path:
save_stack_trace_tsk + 34
blk_mq_insert_requests + 231
blk_mq_flush_plug_list + 281
blk_flush_plug_list + 199
wait_on_page_bit + 192
__filemap_fdatawait_range + 228
filemap_fdatawait_range + 20
filemap_write_and_wait_range + 63
blkdev_fsync + 27
vfs_fsync_range + 73
blkdev_write_iter + 202
__vfs_write + 170
vfs_write + 169
kernel_write + 56
So blk_flush_plug_list() was called with from_schedule == true.
If from_schedule is true, that means that finally blk_mq_insert_requests()
offloads execution of __blk_mq_run_hw_queue() and uses kblockd workqueue,
i.e. it calls kblockd_schedule_delayed_work_on().
That means, that we race with another CPU, which is about to execute
__blk_mq_run_hw_queue() work.
Further debugging shows the following traces from different CPUs:
CPU#0 CPU#1
---------------------------------- -------------------------------
reqeust A inserted
STORE hctx->ctx_map[0] bit marked
kblockd_schedule...() returns 1
<schedule to kblockd workqueue>
request B inserted
STORE hctx->ctx_map[1] bit marked
kblockd_schedule...() returns 0
*** WORK PENDING bit is cleared ***
flush_busy_ctxs() is executed, but
bit 1, set by CPU#1, is not observed
As a result request B pended forever.
This behaviour can be explained by speculative LOAD of hctx->ctx_map on
CPU#0, which is reordered with clear of PENDING bit and executed _before_
actual STORE of bit 1 on CPU#1.
The proper fix is an explicit full barrier <mfence>, which guarantees
that clear of PENDING bit is to be executed before all possible
speculative LOADS or STORES inside actual work function.
Signed-off-by: Roman Pen <roman.penyaev@profitbricks.com>
Cc: Gioh Kim <gi-oh.kim@profitbricks.com>
Cc: Michael Wang <yun.wang@profitbricks.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Tejun Heo <tj@kernel.org>
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cgroup_subsys->post_attach callback
Since e93ad19d0564 ("cpuset: make mm migration asynchronous"), cpuset
kicks off asynchronous NUMA node migration if necessary during task
migration and flushes it from cpuset_post_attach_flush() which is
called at the end of __cgroup_procs_write(). This is to avoid
performing migration with cgroup_threadgroup_rwsem write-locked which
can lead to deadlock through dependency on kworker creation.
memcg has a similar issue with charge moving, so let's convert it to
an official callback rather than the current one-off cpuset specific
function. This patch adds cgroup_subsys->post_attach callback and
makes cpuset register cpuset_post_attach_flush() as its ->post_attach.
The conversion is mostly one-to-one except that the new callback is
called under cgroup_mutex. This is to guarantee that no other
migration operations are started before ->post_attach callbacks are
finished. cgroup_mutex is one of the outermost mutex in the system
and has never been and shouldn't be a problem. We can add specialized
synchronization around __cgroup_procs_write() but I don't think
there's any noticeable benefit.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org> # 4.4+ prerequisite for the next patch
|
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Goal of this patch is to use the new libnl API to align netlink attribute
when needed.
The layout of the netlink message will be a bit different after the patch,
because the padattr (TASKSTATS_TYPE_STATS) will be inside the nested
attribute instead of before it.
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Conflicts were two cases of simple overlapping changes,
nothing serious.
In the UDP case, we need to add a hlist_add_tail_rcu()
to linux/rculist.h, because we've moved UDP socket handling
away from using nulls lists.
Signed-off-by: David S. Miller <davem@davemloft.net>
|
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'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf, cpu hotplug and timer fixes from Ingo Molnar:
"perf:
- A single tooling fix for a user-triggerable segfault.
CPU hotplug:
- Fix a CPU hotplug corner case regression, introduced by the recent
hotplug rework
timers:
- Fix a boot hang in the ARM based Tango SoC clocksource driver"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf intel-pt: Fix segfault tracing transactions
* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
cpu/hotplug: Fix rollback during error-out in __cpu_disable()
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clocksource/drivers/tango-xtal: Fix boot hang due to incorrect test
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Ingo Molnar:
"Misc fixes:
pvqspinlocks:
- an instrumentation fix
futexes:
- preempt-count vs pagefault_disable decouple corner case fix
- futex requeue plist race window fix
- futex UNLOCK_PI transaction fix for a corner case"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
asm-generic/futex: Re-enable preemption in futex_atomic_cmpxchg_inatomic()
futex: Acknowledge a new waiter in counter before plist
futex: Handle unlock_pi race gracefully
locking/pvqspinlock: Fix division by zero in qstat_read()
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fixes from Ingo Molnar:
"A core irq affinity masks related fix and a MIPS irqchip driver fix"
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/mips-gic: Don't overrun pcpu_masks array
genirq: Dont allow affinity mask to be updated on IPIs
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lock_chain::base is used to store an index into the chain_hlocks[]
array, however that array contains more elements than can be indexed
using the u16.
Change the lock_chain structure to use a bitfield to encode the data
it needs and add BUILD_BUG_ON() assertions to check the fields are
wide enough.
Also, for DEBUG_LOCKDEP, assert that we don't run out of elements of
that array; as that would wreck the collision detectoring.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alfredo Alvarez Fernandez <alfredoalvarezfernandez@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160330093659.GS3408@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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task_irq_context() returns the encoded irq_context of the task, the
return value is encoded in the same as ->irq_context of held_lock.
Always return 0 if !(CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING)
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: sasha.levin@oracle.com
Link: http://lkml.kernel.org/r/1455602265-16490-2-git-send-email-boqun.feng@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Markus reported that 0 should also disable the throttling we per
Documentation/sysctl/kernel.txt.
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: 91a612eea9a3 ("perf/core: Fix dynamic interrupt throttle")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
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The recent introduction of the hotplug thread which invokes the callbacks on
the plugged cpu, cased the following regression:
If takedown_cpu() fails, then we run into several issues:
1) The rollback of the target cpu states is not invoked. That leaves the smp
threads and the hotplug thread in disabled state.
2) notify_online() is executed due to a missing skip_onerr flag. That causes
that both CPU_DOWN_FAILED and CPU_ONLINE notifications are invoked which
confuses quite some notifiers.
3) The CPU_DOWN_FAILED notification is not invoked on the target CPU. That's
not an issue per se, but it is inconsistent and in consequence blocks the
patches which rely on these states being invoked on the target CPU and not
on the controlling cpu. It also does not preserve the strict call order on
rollback which is problematic for the ongoing state machine conversion as
well.
To fix this we add a rollback flag to the remote callback machinery and invoke
the rollback including the CPU_DOWN_FAILED notification on the remote
cpu. Further mark the notify online state with 'skip_onerr' so we don't get a
double invokation.
This workaround will go away once we moved the unplug invocation to the target
cpu itself.
[ tglx: Massaged changelog and moved the CPU_DOWN_FAILED notifiaction to the
target cpu ]
Fixes: 4cb28ced23c4 ("cpu/hotplug: Create hotplug threads")
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-s390@vger.kernel.org
Cc: rt@linutronix.de
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Link: http://lkml.kernel.org/r/20160408124015.GA21960@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
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Pull networking fixes from David Miller:
1) Fix memory leak in iwlwifi, from Matti Gottlieb.
2) Add missing registration of netfilter arp_tables into initial
namespace, from Florian Westphal.
3) Fix potential NULL deref in DecNET routing code.
4) Restrict NETLINK_URELEASE to truly bound sockets only, from Dmitry
Ivanov.
5) Fix dst ref counting in VRF, from David Ahern.
6) Fix TSO segmenting limits in i40e driver, from Alexander Duyck.
7) Fix heap leak in PACKET_DIAG_MCLIST, from Mathias Krause.
8) Ravalidate IPV6 datagram socket cached routes properly, particularly
with UDP, from Martin KaFai Lau.
9) Fix endian bug in RDS dp_ack_seq handling, from Qing Huang.
10) Fix stats typing in bcmgenet driver, from Eric Dumazet.
11) Openvswitch needs to orphan SKBs before ipv6 fragmentation handing,
from Joe Stringer.
12) SPI device reference leak in spi_ks8895 PHY driver, from Mark Brown.
13) atl2 doesn't actually support scatter-gather, so don't advertise the
feature. From Ben Hucthings.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (72 commits)
openvswitch: use flow protocol when recalculating ipv6 checksums
Driver: Vmxnet3: set CHECKSUM_UNNECESSARY for IPv6 packets
atl2: Disable unimplemented scatter/gather feature
net/mlx4_en: Split SW RX dropped counter per RX ring
net/mlx4_core: Don't allow to VF change global pause settings
net/mlx4_core: Avoid repeated calls to pci enable/disable
net/mlx4_core: Implement pci_resume callback
net: phy: spi_ks8895: Don't leak references to SPI devices
net: ethernet: davinci_emac: Fix platform_data overwrite
net: ethernet: davinci_emac: Fix Unbalanced pm_runtime_enable
qede: Fix single MTU sized packet from firmware GRO flow
qede: Fix setting Skb network header
qede: Fix various memory allocation error flows for fastpath
tcp: Merge tx_flags and tskey in tcp_shifted_skb
tcp: Merge tx_flags and tskey in tcp_collapse_retrans
drivers: net: cpsw: fix wrong regs access in cpsw_ndo_open
tcp: Fix SOF_TIMESTAMPING_TX_ACK when handling dup acks
openvswitch: Orphan skbs before IPv6 defrag
Revert "Prevent NUll pointer dereference with two PHYs on cpsw"
VSOCK: Only check error on skb_recv_datagram when skb is NULL
...
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move trace_call_bpf() into helper function to minimize the size
of perf_trace_*() tracepoint handlers.
text data bss dec hex filename
10541679 5526646 2945024 19013349 1221ee5 vmlinux_before
10509422 5526646 2945024 18981092 121a0e4 vmlinux_after
It may seem that perf_fetch_caller_regs() can also be moved,
but that is incorrect, since ip/sp will be wrong.
bpf+tracepoint performance is not affected, since
perf_swevent_put_recursion_context() is now inlined.
export_symbol_gpl can also be dropped.
No measurable change in normal perf tracepoints.
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The IPI domain re-purposes the IRQ affinity to signify the mask of CPUs
that this IPI will deliver to. This must not be modified before the IPI
is destroyed again, so set the IRQ_NO_BALANCING flag to prevent the
affinity being overwritten by setup_affinity().
Without this, if an IPI is reserved for a single target CPU, then
allocated using __setup_irq(), the affinity is overwritten with
cpu_online_mask. When ipi_destroy() is subsequently called on a
multi-cpu system, it will attempt to free cpumask_weight() IRQs
that were never allocated, and crash.
Fixes: d17bf24e6952 ("genirq: Add a new generic IPI reservation code to irq core")
Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: jason@lakedaemon.net
Cc: marc.zyngier@arm.com
Cc: ralf@linux-mips.org
Cc: Qais Yousef <qsyousef@gmail.com>
Cc: lisa.parratt@imgtec.com
Link: http://lkml.kernel.org/r/1461229712-13057-1-git-send-email-matt.redfearn@imgtec.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Otherwise an incoming waker on the dest hash bucket can miss
the waiter adding itself to the plist during the lockless
check optimization (small window but still the correct way
of doing this); similarly to the decrement counterpart.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: bigeasy@linutronix.de
Cc: dvhart@infradead.org
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/1461208164-29150-1-git-send-email-dave@stgolabs.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
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If userspace calls UNLOCK_PI unconditionally without trying the TID -> 0
transition in user space first then the user space value might not have the
waiters bit set. This opens the following race:
CPU0 CPU1
uval = get_user(futex)
lock(hb)
lock(hb)
futex |= FUTEX_WAITERS
....
unlock(hb)
cmpxchg(futex, uval, newval)
So the cmpxchg fails and returns -EINVAL to user space, which is wrong because
the futex value is valid.
To handle this (yes, yet another) corner case gracefully, check for a flag
change and retry.
[ tglx: Massaged changelog and slightly reworked implementation ]
Fixes: ccf9e6a80d9e ("futex: Make unlock_pi more robust")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Darren Hart <dvhart@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1460723739-5195-1-git-send-email-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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This patch adds a new helper for cls/act programs that can push events
to user space applications. For networking, this can be f.e. for sampling,
debugging, logging purposes or pushing of arbitrary wake-up events. The
idea is similar to a43eec304259 ("bpf: introduce bpf_perf_event_output()
helper") and 39111695b1b8 ("samples: bpf: add bpf_perf_event_output example").
The eBPF program utilizes a perf event array map that user space populates
with fds from perf_event_open(), the eBPF program calls into the helper
f.e. as skb_event_output(skb, &my_map, BPF_F_CURRENT_CPU, raw, sizeof(raw))
so that the raw data is pushed into the fd f.e. at the map index of the
current CPU.
User space can poll/mmap/etc on this and has a data channel for receiving
events that can be post-processed. The nice thing is that since the eBPF
program and user space application making use of it are tightly coupled,
they can define their own arbitrary raw data format and what/when they
want to push.
While f.e. packet headers could be one part of the meta data that is being
pushed, this is not a substitute for things like packet sockets as whole
packet is not being pushed and push is only done in a single direction.
Intention is more of a generically usable, efficient event pipe to applications.
Workflow is that tc can pin the map and applications can attach themselves
e.g. after cls/act setup to one or multiple map slots, demuxing is done by
the eBPF program.
Adding this facility is with minimal effort, it reuses the helper
introduced in a43eec304259 ("bpf: introduce bpf_perf_event_output() helper")
and we get its functionality for free by overloading its BPF_FUNC_ identifier
for cls/act programs, ctx is currently unused, but will be made use of in
future. Example will be added to iproute2's BPF example files.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Add a BPF_F_CURRENT_CPU flag to optimize the use-case where user space has
per-CPU ring buffers and the eBPF program pushes the data into the current
CPU's ring buffer which saves us an extra helper function call in eBPF.
Also, make sure to properly reserve the remaining flags which are not used.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
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While playing with the qstat statistics (in <debugfs>/qlockstat/) I ran into
the following splat on a VM when opening pv_hash_hops:
divide error: 0000 [#1] SMP
...
RIP: 0010:[<ffffffff810b61fe>] [<ffffffff810b61fe>] qstat_read+0x12e/0x1e0
...
Call Trace:
[<ffffffff811cad7c>] ? mem_cgroup_commit_charge+0x6c/0xd0
[<ffffffff8119750c>] ? page_add_new_anon_rmap+0x8c/0xd0
[<ffffffff8118d3b9>] ? handle_mm_fault+0x1439/0x1b40
[<ffffffff811937a9>] ? do_mmap+0x449/0x550
[<ffffffff811d3de3>] ? __vfs_read+0x23/0xd0
[<ffffffff811d4ab2>] ? rw_verify_area+0x52/0xd0
[<ffffffff811d4bb1>] ? vfs_read+0x81/0x120
[<ffffffff811d5f12>] ? SyS_read+0x42/0xa0
[<ffffffff815720f6>] ? entry_SYSCALL_64_fastpath+0x1e/0xa8
Fix this by verifying that qstat_pv_kick_unlock is in fact non-zero,
similarly to what the qstat_pv_latency_wake case does, as if nothing
else, this can come from resetting the statistics, thus having 0 kicks
should be quite valid in this context.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Reviewed-by: Waiman Long <Waiman.Long@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Cc: waiman.long@hpe.com
Link: http://lkml.kernel.org/r/1460961103-24953-1-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Two new functions in bpf contain a cast from a 'u64' to a
pointer. This works on 64-bit architectures but causes a warning
on all 32-bit architectures:
kernel/trace/bpf_trace.c: In function 'bpf_perf_event_output_tp':
kernel/trace/bpf_trace.c:350:13: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
u64 ctx = *(long *)r1;
This changes the cast to first convert the u64 argument into a uintptr_t,
which is guaranteed to be the same size as a pointer.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 9940d67c93b5 ("bpf: support bpf_get_stackid() and bpf_perf_event_output() in tracepoint programs")
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixlet from Ingo Molnar:
"Fixes a build warning on certain Kconfig combinations"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/lockdep: Fix print_collision() unused warning
|
|
This patch converts all helpers that can use ARG_PTR_TO_RAW_STACK as argument
type. For tc programs this is bpf_skb_load_bytes(), bpf_skb_get_tunnel_key(),
bpf_skb_get_tunnel_opt(). For tracing, this optimizes bpf_get_current_comm()
and bpf_probe_read(). The check in bpf_skb_load_bytes() for MAX_BPF_STACK can
also be removed since the verifier already makes sure we stay within bounds
on stack buffers.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
When passing buffers from eBPF stack space into a helper function, we have
ARG_PTR_TO_STACK argument type for helpers available. The verifier makes sure
that such buffers are initialized, within boundaries, etc.
However, the downside with this is that we have a couple of helper functions
such as bpf_skb_load_bytes() that fill out the passed buffer in the expected
success case anyway, so zero initializing them prior to the helper call is
unneeded/wasted instructions in the eBPF program that can be avoided.
Therefore, add a new helper function argument type called ARG_PTR_TO_RAW_STACK.
The idea is to skip the STACK_MISC check in check_stack_boundary() and color
the related stack slots as STACK_MISC after we checked all call arguments.
Helper functions using ARG_PTR_TO_RAW_STACK must make sure that every path of
the helper function will fill the provided buffer area, so that we cannot leak
any uninitialized stack memory. This f.e. means that error paths need to
memset() the buffers, but the expected fast-path doesn't have to do this
anymore.
Since there's no such helper needing more than at most one ARG_PTR_TO_RAW_STACK
argument, we can keep it simple and don't need to check for multiple areas.
Should in future such a use-case really appear, we have check_raw_mode() that
will make sure we implement support for it first.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Currently, when the verifier checks calls in check_call() function, we
call check_func_arg() for all 5 arguments e.g. to make sure expected types
are correct. In some cases, we collect meta data (here: map pointer) to
perform additional checks such as checking stack boundary on key/value
sizes for subsequent arguments. As we're going to extend the meta data,
add a generic struct bpf_call_arg_meta that we can use for passing into
check_func_arg().
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
In commit c4004b02f8e5b ("x86: remove the kernel code/data/bss resources
from /proc/iomem") I was hoping to remove the phyiscal kernel address
data from /proc/iomem entirely, but that had to be reverted because some
system programs actually use it.
This limits all the detailed resource information to properly
credentialed users instead.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
verifier must check for reserved size bits in instruction opcode and
reject BPF_LD | BPF_ABS | BPF_DW and BPF_LD | BPF_IND | BPF_DW instructions,
otherwise interpreter will WARN_RATELIMIT on them during execution.
Fixes: ddd872bc3098 ("bpf: verifier: add checks for BPF_ABS | BPF_IND instructions")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
verifier is using the following structure to track the state of registers:
struct reg_state {
enum bpf_reg_type type;
union {
int imm;
struct bpf_map *map_ptr;
};
};
and later on in states_equal() does memcmp(&old->regs[i], &cur->regs[i],..)
to find equivalent states.
Throughout the code of verifier there are assignements to 'imm' and 'map_ptr'
fields and it's not obvious that most of the assignments into 'imm' don't
need to clear extra 4 bytes (like mark_reg_unknown_value() does) to make sure
that memcmp doesn't go over junk left from 'map_ptr' assignment.
Simplify the code by converting 'int' into 'long'
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
|
|
The verifier needs to go through every path of the program in
order to check that it terminates safely, which can be quite a
lot of instructions that need to be processed f.e. in cases with
more branchy programs. With search pruning from f1bca824dabb ("bpf:
add search pruning optimization to verifier") the search space can
already be reduced significantly when the verifier detects that
a previously walked path with same register and stack contents
terminated already (see verifier's states_equal()), so the search
can skip walking those states.
When working with larger programs of > ~2000 (out of max 4096)
insns, we found that the current limit of 32k instructions is easily
hit. For example, a case we ran into is that the search space cannot
be pruned due to branches at the beginning of the program that make
use of certain stack space slots (STACK_MISC), which are never used
in the remaining program (STACK_INVALID). Therefore, the verifier
needs to walk paths for the slots in STACK_INVALID state, but also
all remaining paths with a stack structure, where the slots are in
STACK_MISC, which can nearly double the search space needed. After
various experiments, we find that a limit of 64k processed insns is
a more reasonable choice when dealing with larger programs in practice.
This still allows to reject extreme crafted cases that can have a
much higher complexity (f.e. > ~300k) within the 4096 insns limit
due to search pruning not being able to take effect.
Furthermore, we found that a lot of states can be pruned after a
call instruction, f.e. we were able to reduce the search state by
~35% in some cases with this heuristic, trade-off is to keep a bit
more states in env->explored_states. Usually, call instructions
have a number of preceding register assignments and/or stack stores,
where search pruning has a better chance to suceed in states_equal()
test. The current code marks the branch targets with STATE_LIST_MARK
in case of conditional jumps, and the next (t + 1) instruction in
case of unconditional jump so that f.e. a backjump will walk it. We
also did experiments with using t + insns[t].off + 1 as a marker in
the unconditionally jump case instead of t + 1 with the rationale
that these two branches of execution that converge after the label
might have more potential of pruning. We found that it was a bit
better, but not necessarily significantly better than the current
state, perhaps also due to clang not generating back jumps often.
Hence, we left that as is for now.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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during bpf program loading remember the last byte of ctx access
and at the time of attaching the program to tracepoint check that
the program doesn't access bytes beyond defined in tracepoint fields
This also disallows access to __dynamic_array fields, but can be
relaxed in the future.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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