Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
code
Clone this repository
https://tangled.org/tjh.dev/kernel
git@gordian.tjh.dev:tjh.dev/kernel
For self-hosted knots, clone URLs may differ based on your setup.
Pull networking fixes from David Miller:
"A decent batch of fixes here. I'd say about half are for problems that
have existed for a while, and half are for new regressions added in
the 4.20 merge window.
1) Fix 10G SFP phy module detection in mvpp2, from Baruch Siach.
2) Revert bogus emac driver change, from Benjamin Herrenschmidt.
3) Handle BPF exported data structure with pointers when building
32-bit userland, from Daniel Borkmann.
4) Memory leak fix in act_police, from Davide Caratti.
5) Check RX checksum offload in RX descriptors properly in aquantia
driver, from Dmitry Bogdanov.
6) SKB unlink fix in various spots, from Edward Cree.
7) ndo_dflt_fdb_dump() only works with ethernet, enforce this, from
Eric Dumazet.
8) Fix FID leak in mlxsw driver, from Ido Schimmel.
9) IOTLB locking fix in vhost, from Jean-Philippe Brucker.
10) Fix SKB truesize accounting in ipv4/ipv6/netfilter frag memory
limits otherwise namespace exit can hang. From Jiri Wiesner.
11) Address block parsing length fixes in x25 from Martin Schiller.
12) IRQ and ring accounting fixes in bnxt_en, from Michael Chan.
13) For tun interfaces, only iface delete works with rtnl ops, enforce
this by disallowing add. From Nicolas Dichtel.
14) Use after free in liquidio, from Pan Bian.
15) Fix SKB use after passing to netif_receive_skb(), from Prashant
Bhole.
16) Static key accounting and other fixes in XPS from Sabrina Dubroca.
17) Partially initialized flow key passed to ip6_route_output(), from
Shmulik Ladkani.
18) Fix RTNL deadlock during reset in ibmvnic driver, from Thomas
Falcon.
19) Several small TCP fixes (off-by-one on window probe abort, NULL
deref in tail loss probe, SNMP mis-estimations) from Yuchung
Cheng"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (93 commits)
net/sched: cls_flower: Reject duplicated rules also under skip_sw
bnxt_en: Fix _bnxt_get_max_rings() for 57500 chips.
bnxt_en: Fix NQ/CP rings accounting on the new 57500 chips.
bnxt_en: Keep track of reserved IRQs.
bnxt_en: Fix CNP CoS queue regression.
net/mlx4_core: Correctly set PFC param if global pause is turned off.
Revert "net/ibm/emac: wrong bit is used for STA control"
neighbour: Avoid writing before skb->head in neigh_hh_output()
ipv6: Check available headroom in ip6_xmit() even without options
tcp: lack of available data can also cause TSO defer
ipv6: sr: properly initialize flowi6 prior passing to ip6_route_output
mlxsw: spectrum_switchdev: Fix VLAN device deletion via ioctl
mlxsw: spectrum_router: Relax GRE decap matching check
mlxsw: spectrum_switchdev: Avoid leaking FID's reference count
mlxsw: spectrum_nve: Remove easily triggerable warnings
ipv4: ipv6: netfilter: Adjust the frag mem limit when truesize changes
sctp: frag_point sanity check
tcp: fix NULL ref in tail loss probe
tcp: Do not underestimate rwnd_limited
net: use skb_list_del_init() to remove from RX sublists
...
Pull x86 fixes from Ingo Molnar:
"Three fixes: a boot parameter re-(re-)fix, a retpoline build artifact
fix and an LLVM workaround"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/vdso: Drop implicit common-page-size linker flag
x86/build: Fix compiler support check for CONFIG_RETPOLINE
x86/boot: Clear RSDP address in boot_params for broken loaders
Currently, duplicated rules are rejected only for skip_hw or "none",
hence allowing users to push duplicates into HW for no reason.
Use the flower tables to protect for that.
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Paul Blakey <paulb@mellanox.com>
Reported-by: Chris Mi <chrism@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull kprobes fixes from Ingo Molnar:
"Two kprobes fixes: a blacklist fix and an instruction patching related
corruption fix"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
kprobes/x86: Blacklist non-attachable interrupt functions
kprobes/x86: Fix instruction patching corruption when copying more than one RIP-relative instruction
GNU linker's -z common-page-size's default value is based on the target
architecture. arch/x86/entry/vdso/Makefile sets it to the architecture
default, which is implicit and redundant. Drop it.
Fixes: 2aae950b21e4 ("x86_64: Add vDSO for x86-64 with gettimeofday/clock_gettime/getcpu")
Reported-by: Dmitry Golovin <dima@golovin.in>
Reported-by: Bill Wendling <morbo@google.com>
Suggested-by: Dmitry Golovin <dima@golovin.in>
Suggested-by: Rui Ueyama <ruiu@google.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Fangrui Song <maskray@google.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20181206191231.192355-1-ndesaulniers@google.com
Link: https://bugs.llvm.org/show_bug.cgi?id=38774
Link: https://github.com/ClangBuiltLinux/linux/issues/31
Michael Chan says:
====================
bnxt_en: Bug fixes.
The first patch fixes a regression on CoS queue setup, introduced
recently by the 57500 new chip support patches. The rest are
fixes related to ring and resource accounting on the new 57500 chips.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull EFI fixes from Ingo Molnar:
"Two fixes: a large-system fix and an earlyprintk fix with certain
resolutions"
* 'efi-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/earlyprintk/efi: Fix infinite loop on some screen widths
x86/efi: Allocate e820 buffer before calling efi_exit_boot_service
These interrupt functions are already non-attachable by kprobes.
Blacklist them explicitly so that they can show up in
/sys/kernel/debug/kprobes/blacklist and tools like BCC can use this
additional information.
Signed-off-by: Andrea Righi <righi.andrea@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yonghong Song <yhs@fb.com>
Link: http://lkml.kernel.org/r/20181206095648.GA8249@Dell
Signed-off-by: Ingo Molnar <mingo@kernel.org>
It is troublesome to add a diagnostic like this to the Makefile
parse stage because the top-level Makefile could be parsed with
a stale include/config/auto.conf.
Once you are hit by the error about non-retpoline compiler, the
compilation still breaks even after disabling CONFIG_RETPOLINE.
The easiest fix is to move this check to the "archprepare" like
this commit did:
829fe4aa9ac1 ("x86: Allow generating user-space headers without a compiler")
Reported-by: Meelis Roos <mroos@linux.ee>
Tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Fixes: 4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support")
Link: http://lkml.kernel.org/r/1543991239-18476-1-git-send-email-yamada.masahiro@socionext.com
Link: https://lkml.org/lkml/2018/12/4/206
Signed-off-by: Ingo Molnar <mingo@kernel.org>
rx_ppp and tx_ppp can be set between 0 and 255, so don't clamp to 1.
Fixes: 6e8814ceb7e8 ("net/mlx4_en: Fix mixed PFC and Global pause user control requests")
Signed-off-by: Tarick Bedeir <tarick@google.com>
Reviewed-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The CP rings are accounted differently on the new 57500 chips. There
must be enough CP rings for the sum of RX and TX rings on the new
chips. The current logic may be over-estimating the RX and TX rings.
The output parameter max_cp should be the maximum NQs capped by
MSIX vectors available for networking in the context of 57500 chips.
The existing code which uses CMPL rings capped by the MSIX vectors
works most of the time but is not always correct.
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull char/misc driver fixes from Greg KH:
"Here are some small driver fixes for 4.20-rc6.
There is a hyperv fix that for some reaon took forever to get into a
shape that could be applied to the tree properly, but resolves a much
reported issue. The others are some gnss patches, one a bugfix and the
two others updates to the MAINTAINERS file to properly match the gnss
files in the tree.
All have been in linux-next for a while with no reported issues"
* tag 'char-misc-4.20-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
MAINTAINERS: exclude gnss from SIRFPRIMA2 regex matching
MAINTAINERS: add gnss scm tree
gnss: sirf: fix activation retry handling
Drivers: hv: vmbus: Offload the handling of channels to two workqueues
An affected screen resolution is 1366 x 768, which width is not
divisible by 8, the default font width. On such screens, when longer
lines are earlyprintk'ed, overflow-to-next-line can never trigger,
due to the left-most x-coordinate of the next character always less
than the screen width. Earlyprintk will infinite loop in trying to
print the rest of the string but unable to, due to the line being
full.
This patch makes the trigger consider the right-most x-coordinate,
instead of left-most, as the value to compare against the screen
width threshold.
Signed-off-by: YiFei Zhu <zhuyifei1999@gmail.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arend van Spriel <arend.vanspriel@broadcom.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Eric Snowberg <eric.snowberg@oracle.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jon Hunter <jonathanh@nvidia.com>
Cc: Julien Thierry <julien.thierry@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20181129171230.18699-12-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
After copy_optimized_instructions() copies several instructions
to the working buffer it tries to fix up the real RIP address, but it
adjusts the RIP-relative instruction with an incorrect RIP address
for the 2nd and subsequent instructions due to a bug in the logic.
This will break the kernel pretty badly (with likely outcomes such as
a kernel freeze, a crash, or worse) because probed instructions can refer
to the wrong data.
For example putting kprobes on cpumask_next() typically hits this bug.
cpumask_next() is normally like below if CONFIG_CPUMASK_OFFSTACK=y
(in this case nr_cpumask_bits is an alias of nr_cpu_ids):
<cpumask_next>:
48 89 f0 mov %rsi,%rax
8b 35 7b fb e2 00 mov 0xe2fb7b(%rip),%esi # ffffffff82db9e64 <nr_cpu_ids>
55 push %rbp
...
If we put a kprobe on it and it gets jump-optimized, it gets
patched by the kprobes code like this:
<cpumask_next>:
e9 95 7d 07 1e jmpq 0xffffffffa000207a
7b fb jnp 0xffffffff81f8a2e2 <cpumask_next+2>
e2 00 loop 0xffffffff81f8a2e9 <cpumask_next+9>
55 push %rbp
This shows that the first two MOV instructions were copied to a
trampoline buffer at 0xffffffffa000207a.
Here is the disassembled result of the trampoline, skipping
the optprobe template instructions:
# Dump of assembly code from 0xffffffffa000207a to 0xffffffffa00020ea:
54 push %rsp
...
48 83 c4 08 add $0x8,%rsp
9d popfq
48 89 f0 mov %rsi,%rax
8b 35 82 7d db e2 mov -0x1d24827e(%rip),%esi # 0xffffffff82db9e67 <nr_cpu_ids+3>
This dump shows that the second MOV accesses *(nr_cpu_ids+3) instead of
the original *nr_cpu_ids. This leads to a kernel freeze because
cpumask_next() always returns 0 and for_each_cpu() never ends.
Fix this by adding 'len' correctly to the real RIP address while
copying.
[ mingo: Improved the changelog. ]
Reported-by: Michael Rodin <michael@rodin.online>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org # v4.15+
Fixes: 63fef14fc98a ("kprobes/x86: Make insn buffer always ROX and use text_poke()")
Link: http://lkml.kernel.org/r/153504457253.22602.1314289671019919596.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>