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GCC already checks for arguments that are marked with the "nonstring"[1]
attribute when used on standard C String API functions (e.g. strcpy). Gain
this compile-time checking also for the kernel's primary string copying
function, strscpy().
Note that Clang has neither "nonstring" nor __builtin_has_attribute().
Link: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-nonstring-variable-attribute [1]
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Tested-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/r/20240805214340.work.339-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
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Some code includes the __used macro to prevent functions and data from
being optimized out. This macro implements __attribute__((__used__)),
which operates at the compiler and IR-level, and so still allows a linker
to remove objects intended to be kept.
Compilers supporting __attribute__((__retain__)) can address this gap by
setting the flag SHF_GNU_RETAIN on the section of a function/variable,
indicating to the linker the object should be retained. This attribute is
available since gcc 11, clang 13, and binutils 2.36.
Provide a __retain macro implementing __attribute__((__retain__)), whose
first user will be the '__bpf_kfunc' tag.
[ Additional remark from discussion:
Why is CONFIG_LTO_CLANG added here? The __used macro permits garbage
collection at section level, so CLANG_LTO_CLANG without
CONFIG_LD_DEAD_CODE_DATA_ELIMINATION should not change final section
dynamics?
The conditional guard was included to ensure consistent behaviour
between __retain and other features forcing split sections. In
particular, the same guard is used in vmlinux.lds.h to merge split
sections where needed. For example, using __retain in LLVM builds
without CONFIG_LTO was failing CI tests on kernel-patches/bpf because
the kernel didn't boot properly. And in further testing, the kernel
had no issues loading BPF kfunc modules with such split sections, so
the module (partial) linking scripts were left alone. ]
Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/ZlmGoT9KiYLZd91S@krava/T/
Link: https://lore.kernel.org/bpf/b31bca5a5e6765a0f32cc8c19b1d9cdbfaa822b5.1717477560.git.Tony.Ambardar@gmail.com
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Merge trivial x86 code generation annoyances
- Introduce helper macros for clang asm input problems
- use said macros to improve trivially stupid code generation issues in
bitops and array_index_mask_nospec
- also improve codegen with 32-bit array index comparisons
None of these really matter, but I look at code generation and profiles
fairly regularly, and these misfeatures caused the generated code to
look really odd and distract from the real issues.
* branch 'x86-codegen' of local tree:
x86: improve bitop code generation with clang
x86: improve array_index_mask_nospec() code generation
clang: work around asm input constraint problems
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Work around clang problems with asm constraints that have multiple
possibilities, particularly "g" and "rm".
Clang seems to turn inputs like that into the most generic form, which
is the memory input - but to make matters worse, clang won't even use a
possible original memory location, but will spill the value to stack,
and use the stack for the asm input.
See
https://github.com/llvm/llvm-project/issues/20571#issuecomment-980933442
for some explanation of why clang has this strange behavior, but the end
result is that "g" and "rm" really end up generating horrid code.
Link: https://github.com/llvm/llvm-project/issues/20571
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from Jakub Kicinski:
"Core & protocols:
- Complete rework of garbage collection of AF_UNIX sockets.
AF_UNIX is prone to forming reference count cycles due to fd
passing functionality. New method based on Tarjan's Strongly
Connected Components algorithm should be both faster and remove a
lot of workarounds we accumulated over the years.
- Add TCP fraglist GRO support, allowing chaining multiple TCP
packets and forwarding them together. Useful for small switches /
routers which lack basic checksum offload in some scenarios (e.g.
PPPoE).
- Support using SMP threads for handling packet backlog i.e. packet
processing from software interfaces and old drivers which don't use
NAPI. This helps move the processing out of the softirq jumble.
- Continue work of converting from rtnl lock to RCU protection.
Don't require rtnl lock when reading: IPv6 routing FIB, IPv6
address labels, netdev threaded NAPI sysfs files, bonding driver's
sysfs files, MPLS devconf, IPv4 FIB rules, netns IDs, tcp metrics,
TC Qdiscs, neighbor entries, ARP entries via ioctl(SIOCGARP), a lot
of the link information available via rtnetlink.
- Small optimizations from Eric to UDP wake up handling, memory
accounting, RPS/RFS implementation, TCP packet sizing etc.
- Allow direct page recycling in the bulk API used by XDP, for +2%
PPS.
- Support peek with an offset on TCP sockets.
- Add MPTCP APIs for querying last time packets were received/sent/acked
and whether MPTCP "upgrade" succeeded on a TCP socket.
- Add intra-node communication shortcut to improve SMC performance.
- Add IPv6 (and IPv{4,6}-over-IPv{4,6}) support to the GTP protocol
driver.
- Add HSR-SAN (RedBOX) mode of operation to the HSR protocol driver.
- Add reset reasons for tracing what caused a TCP reset to be sent.
- Introduce direction attribute for xfrm (IPSec) states. State can be
used either for input or output packet processing.
Things we sprinkled into general kernel code:
- Add bitmap_{read,write}(), bitmap_size(), expose BYTES_TO_BITS().
This required touch-ups and renaming of a few existing users.
- Add Endian-dependent __counted_by_{le,be} annotations.
- Make building selftests "quieter" by printing summaries like
"CC object.o" rather than full commands with all the arguments.
Netfilter:
- Use GFP_KERNEL to clone elements, to deal better with OOM
situations and avoid failures in the .commit step.
BPF:
- Add eBPF JIT for ARCv2 CPUs.
- Support attaching kprobe BPF programs through kprobe_multi link in
a session mode, meaning, a BPF program is attached to both function
entry and return, the entry program can decide if the return
program gets executed and the entry program can share u64 cookie
value with return program. "Session mode" is a common use-case for
tetragon and bpftrace.
- Add the ability to specify and retrieve BPF cookie for raw
tracepoint programs in order to ease migration from classic to raw
tracepoints.
- Add an internal-only BPF per-CPU instruction for resolving per-CPU
memory addresses and implement support in x86, ARM64 and RISC-V
JITs. This allows inlining functions which need to access per-CPU
state.
- Optimize x86 BPF JIT's emit_mov_imm64, and add support for various
atomics in bpf_arena which can be JITed as a single x86
instruction. Support BPF arena on ARM64.
- Add a new bpf_wq API for deferring events and refactor
process-context bpf_timer code to keep common code where possible.
- Harden the BPF verifier's and/or/xor value tracking.
- Introduce crypto kfuncs to let BPF programs call kernel crypto
APIs.
- Support bpf_tail_call_static() helper for BPF programs with GCC 13.
- Add bpf_preempt_{disable,enable}() kfuncs in order to allow a BPF
program to have code sections where preemption is disabled.
Driver API:
- Skip software TC processing completely if all installed rules are
marked as HW-only, instead of checking the HW-only flag rule by
rule.
- Add support for configuring PoE (Power over Ethernet), similar to
the already existing support for PoDL (Power over Data Line)
config.
- Initial bits of a queue control API, for now allowing a single
queue to be reset without disturbing packet flow to other queues.
- Common (ethtool) statistics for hardware timestamping.
Tests and tooling:
- Remove the need to create a config file to run the net forwarding
tests so that a naive "make run_tests" can exercise them.
- Define a method of writing tests which require an external endpoint
to communicate with (to send/receive data towards the test
machine). Add a few such tests.
- Create a shared code library for writing Python tests. Expose the
YAML Netlink library from tools/ to the tests for easy Netlink
access.
- Move netfilter tests under net/, extend them, separate performance
tests from correctness tests, and iron out issues found by running
them "on every commit".
- Refactor BPF selftests to use common network helpers.
- Further work filling in YAML definitions of Netlink messages for:
nftables, team driver, bonding interfaces, vlan interfaces, VF
info, TC u32 mark, TC police action.
- Teach Python YAML Netlink to decode attribute policies.
- Extend the definition of the "indexed array" construct in the specs
to cover arrays of scalars rather than just nests.
- Add hyperlinks between definitions in generated Netlink docs.
Drivers:
- Make sure unsupported flower control flags are rejected by drivers,
and make more drivers report errors directly to the application
rather than dmesg (large number of driver changes from Asbjørn
Sloth Tønnesen).
- Ethernet high-speed NICs:
- Broadcom (bnxt):
- support multiple RSS contexts and steering traffic to them
- support XDP metadata
- make page pool allocations more NUMA aware
- Intel (100G, ice, idpf):
- extract datapath code common among Intel drivers into a library
- use fewer resources in switchdev by sharing queues with the PF
- add PFCP filter support
- add Ethernet filter support
- use a spinlock instead of HW lock in PTP clock ops
- support 5 layer Tx scheduler topology
- nVidia/Mellanox:
- 800G link modes and 100G SerDes speeds
- per-queue IRQ coalescing configuration
- Marvell Octeon:
- support offloading TC packet mark action
- Ethernet NICs consumer, embedded and virtual:
- stop lying about skb->truesize in USB Ethernet drivers, it
messes up TCP memory calculations
- Google cloud vNIC:
- support changing ring size via ethtool
- support ring reset using the queue control API
- VirtIO net:
- expose flow hash from RSS to XDP
- per-queue statistics
- add selftests
- Synopsys (stmmac):
- support controllers which require an RX clock signal from the
MII bus to perform their hardware initialization
- TI:
- icssg_prueth: support ICSSG-based Ethernet on AM65x SR1.0 devices
- icssg_prueth: add SW TX / RX Coalescing based on hrtimers
- cpsw: minimal XDP support
- Renesas (ravb):
- support describing the MDIO bus
- Realtek (r8169):
- add support for RTL8168M
- Microchip Sparx5:
- matchall and flower actions mirred and redirect
- Ethernet switches:
- nVidia/Mellanox:
- improve events processing performance
- Marvell:
- add support for MV88E6250 family internal PHYs
- Microchip:
- add DCB and DSCP mapping support for KSZ switches
- vsc73xx: convert to PHYLINK
- Realtek:
- rtl8226b/rtl8221b: add C45 instances and SerDes switching
- Many driver changes related to PHYLIB and PHYLINK deprecated API
cleanup
- Ethernet PHYs:
- Add a new driver for Airoha EN8811H 2.5 Gigabit PHY.
- micrel: lan8814: add support for PPS out and external timestamp trigger
- WiFi:
- Disable Wireless Extensions (WEXT) in all Wi-Fi 7 devices
drivers. Modern devices can only be configured using nl80211.
- mac80211/cfg80211
- handle color change per link for WiFi 7 Multi-Link Operation
- Intel (iwlwifi):
- don't support puncturing in 5 GHz
- support monitor mode on passive channels
- BZ-W device support
- P2P with HE/EHT support
- re-add support for firmware API 90
- provide channel survey information for Automatic Channel Selection
- MediaTek (mt76):
- mt7921 LED control
- mt7925 EHT radiotap support
- mt7920e PCI support
- Qualcomm (ath11k):
- P2P support for QCA6390, WCN6855 and QCA2066
- support hibernation
- ieee80211-freq-limit Device Tree property support
- Qualcomm (ath12k):
- refactoring in preparation of multi-link support
- suspend and hibernation support
- ACPI support
- debugfs support, including dfs_simulate_radar support
- RealTek:
- rtw88: RTL8723CS SDIO device support
- rtw89: RTL8922AE Wi-Fi 7 PCI device support
- rtw89: complete features of new WiFi 7 chip 8922AE including
BT-coexistence and Wake-on-WLAN
- rtw89: use BIOS ACPI settings to set TX power and channels
- rtl8xxxu: enable Management Frame Protection (MFP) support
- Bluetooth:
- support for Intel BlazarI and Filmore Peak2 (BE201)
- support for MediaTek MT7921S SDIO
- initial support for Intel PCIe BT driver
- remove HCI_AMP support"
* tag 'net-next-6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1827 commits)
selftests: netfilter: fix packetdrill conntrack testcase
net: gro: fix napi_gro_cb zeroed alignment
Bluetooth: btintel_pcie: Refactor and code cleanup
Bluetooth: btintel_pcie: Fix warning reported by sparse
Bluetooth: hci_core: Fix not handling hdev->le_num_of_adv_sets=1
Bluetooth: btintel: Fix compiler warning for multi_v7_defconfig config
Bluetooth: btintel_pcie: Fix compiler warnings
Bluetooth: btintel_pcie: Add *setup* function to download firmware
Bluetooth: btintel_pcie: Add support for PCIe transport
Bluetooth: btintel: Export few static functions
Bluetooth: HCI: Remove HCI_AMP support
Bluetooth: L2CAP: Fix div-by-zero in l2cap_le_flowctl_init()
Bluetooth: qca: Fix error code in qca_read_fw_build_info()
Bluetooth: hci_conn: Use __counted_by() and avoid -Wfamnae warning
Bluetooth: btintel: Add support for Filmore Peak2 (BE201)
Bluetooth: btintel: Add support for BlazarI
LE Create Connection command timeout increased to 20 secs
dt-bindings: net: bluetooth: Add MediaTek MT7921S SDIO Bluetooth
Bluetooth: compute LE flow credits based on recvbuf space
Bluetooth: hci_sync: Use cmd->num_cis instead of magic number
...
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git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu
Pull kcsan update from Paul McKenney:
"Introduce __data_racy type qualifier
This adds a __data_racy type qualifier that enables kernel developers
to inform KCSAN that a given variable is a shared variable without
needing to mark each and every access.
This allows pre-KCSAN code to be correctly (if approximately)
instrumented withh very little effort, and also provides people
reading the code a clear indication that the variable is in fact
shared.
In addition, it permits incremental transition to per-access KCSAN
marking, so that (for example) a given subsystem can be transitioned
one variable at a time, while avoiding large numbers of KCSAN warnings
during this transition"
* tag 'kcsan.2024.05.10a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
kcsan, compiler_types: Introduce __data_racy type qualifier
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Based on the discussion at [1], it would be helpful to mark certain
variables as explicitly "data racy", which would result in KCSAN not
reporting data races involving any accesses on such variables. To do
that, introduce the __data_racy type qualifier:
struct foo {
...
int __data_racy bar;
...
};
In KCSAN-kernels, __data_racy turns into volatile, which KCSAN already
treats specially by considering them "marked". In non-KCSAN kernels the
type qualifier turns into no-op.
The generated code between KCSAN-instrumented kernels and non-KCSAN
kernels is already huge (inserted calls into runtime for every memory
access), so the extra generated code (if any) due to volatile for few
such __data_racy variables are unlikely to have measurable impact on
performance.
Link: https://lore.kernel.org/all/CAHk-=wi3iondeh_9V2g3Qz5oHTRjLsOpoy83hb58MVh=nRZe0A@mail.gmail.com/ [1]
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Marco Elver <elver@google.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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It turned out that KMSAN instruments READ_ONCE_NOCHECK(), resulting in
false positive reports, because __no_sanitize_or_inline enforced inlining.
Properly declare __no_sanitize_or_inline under __SANITIZE_MEMORY__, so
that it does not __always_inline the annotated function.
Link: https://lkml.kernel.org/r/20240426091622.3846771-1-glider@google.com
Fixes: 5de0ce85f5a4 ("kmsan: mark noinstr as __no_sanitize_memory")
Signed-off-by: Alexander Potapenko <glider@google.com>
Reported-by: syzbot+355c5bb8c1445c871ee8@syzkaller.appspotmail.com
Link: https://lkml.kernel.org/r/000000000000826ac1061675b0e3@google.com
Cc: <stable@vger.kernel.org>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Some structures contain flexible arrays at the end and the counter for
them, but the counter has explicit Endianness and thus __counted_by()
can't be used directly.
To increase test coverage for potential problems without breaking
anything, introduce __counted_by_{le,be}() defined depending on
platform's Endianness to either __counted_by() when applicable or noop
otherwise.
Maybe it would be a good idea to introduce such attributes on compiler
level if possible, but for now let's stop on what we have.
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Link: https://lore.kernel.org/r/20240327142241.1745989-2-aleksander.lobakin@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Generate a list of built DTB files (arch/*/boot/dts/dtbs-list)
- Use more threads when building Debian packages in parallel
- Fix warnings shown during the RPM kernel package uninstallation
- Change OBJECT_FILES_NON_STANDARD_*.o etc. to take a relative path to
Makefile
- Support GCC's -fmin-function-alignment flag
- Fix a null pointer dereference bug in modpost
- Add the DTB support to the RPM package
- Various fixes and cleanups in Kconfig
* tag 'kbuild-v6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (67 commits)
kconfig: tests: test dependency after shuffling choices
kconfig: tests: add a test for randconfig with dependent choices
kconfig: tests: support KCONFIG_SEED for the randconfig runner
kbuild: rpm-pkg: add dtb files in kernel rpm
kconfig: remove unneeded menu_is_visible() call in conf_write_defconfig()
kconfig: check prompt for choice while parsing
kconfig: lxdialog: remove unused dialog colors
kconfig: lxdialog: fix button color for blackbg theme
modpost: fix null pointer dereference
kbuild: remove GCC's default -Wpacked-bitfield-compat flag
kbuild: unexport abs_srctree and abs_objtree
kbuild: Move -Wenum-{compare-conditional,enum-conversion} into W=1
kconfig: remove named choice support
kconfig: use linked list in get_symbol_str() to iterate over menus
kconfig: link menus to a symbol
kbuild: fix inconsistent indentation in top Makefile
kbuild: Use -fmin-function-alignment when available
alpha: merge two entries for CONFIG_ALPHA_GAMMA
alpha: merge two entries for CONFIG_ALPHA_EV4
kbuild: change DTC_FLAGS_<basetarget>.o to take the path relative to $(obj)
...
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git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull hardening updates from Kees Cook:
"As is pretty normal for this tree, there are changes all over the
place, especially for small fixes, selftest improvements, and improved
macro usability.
Some header changes ended up landing via this tree as they depended on
the string header cleanups. Also, a notable set of changes is the work
for the reintroduction of the UBSAN signed integer overflow sanitizer
so that we can continue to make improvements on the compiler side to
make this sanitizer a more viable future security hardening option.
Summary:
- string.h and related header cleanups (Tanzir Hasan, Andy
Shevchenko)
- VMCI memcpy() usage and struct_size() cleanups (Vasiliy Kovalev,
Harshit Mogalapalli)
- selftests/powerpc: Fix load_unaligned_zeropad build failure
(Michael Ellerman)
- hardened Kconfig fragment updates (Marco Elver, Lukas Bulwahn)
- Handle tail call optimization better in LKDTM (Douglas Anderson)
- Use long form types in overflow.h (Andy Shevchenko)
- Add flags param to string_get_size() (Andy Shevchenko)
- Add Coccinelle script for potential struct_size() use (Jacob
Keller)
- Fix objtool corner case under KCFI (Josh Poimboeuf)
- Drop 13 year old backward compat CAP_SYS_ADMIN check (Jingzi Meng)
- Add str_plural() helper (Michal Wajdeczko, Kees Cook)
- Ignore relocations in .notes section
- Add comments to explain how __is_constexpr() works
- Fix m68k stack alignment expectations in stackinit Kunit test
- Convert string selftests to KUnit
- Add KUnit tests for fortified string functions
- Improve reporting during fortified string warnings
- Allow non-type arg to type_max() and type_min()
- Allow strscpy() to be called with only 2 arguments
- Add binary mode to leaking_addresses scanner
- Various small cleanups to leaking_addresses scanner
- Adding wrapping_*() arithmetic helper
- Annotate initial signed integer wrap-around in refcount_t
- Add explicit UBSAN section to MAINTAINERS
- Fix UBSAN self-test warnings
- Simplify UBSAN build via removal of CONFIG_UBSAN_SANITIZE_ALL
- Reintroduce UBSAN's signed overflow sanitizer"
* tag 'hardening-v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (51 commits)
selftests/powerpc: Fix load_unaligned_zeropad build failure
string: Convert helpers selftest to KUnit
string: Convert selftest to KUnit
sh: Fix build with CONFIG_UBSAN=y
compiler.h: Explain how __is_constexpr() works
overflow: Allow non-type arg to type_max() and type_min()
VMCI: Fix possible memcpy() run-time warning in vmci_datagram_invoke_guest_handler()
lib/string_helpers: Add flags param to string_get_size()
x86, relocs: Ignore relocations in .notes section
objtool: Fix UNWIND_HINT_{SAVE,RESTORE} across basic blocks
overflow: Use POD in check_shl_overflow()
lib: stackinit: Adjust target string to 8 bytes for m68k
sparc: vdso: Disable UBSAN instrumentation
kernel.h: Move lib/cmdline.c prototypes to string.h
leaking_addresses: Provide mechanism to scan binary files
leaking_addresses: Ignore input device status lines
leaking_addresses: Use File::Temp for /tmp files
MAINTAINERS: Update LEAKING_ADDRESSES details
fortify: Improve buffer overflow reporting
fortify: Add KUnit tests for runtime overflows
...
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GCC recently added option -fmin-function-alignment, which should appear
in GCC 14. Unlike -falign-functions, this option causes all functions to
be aligned at the specified value, including the cold ones.
In particular, when an arm64 kernel is built with
DYNAMIC_FTRACE_WITH_CALL_OPS=y, the 8-byte function alignment is
required for correct functionality. This was done by -falign-functions=8
and having workarounds in the kernel to force the compiler to follow
this alignment. The new -fmin-function-alignment option directly
guarantees it.
Detect availability of -fmin-function-alignment and use it instead of
-falign-functions when present. Introduce CC_HAS_SANE_FUNCTION_ALIGNMENT
and enable __cold to work as expected when it is set.
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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In order to mitigate unexpected signed wrap-around[1], bring back the
signed integer overflow sanitizer. It was removed in commit 6aaa31aeb9cf
("ubsan: remove overflow checks") because it was effectively a no-op
when combined with -fno-strict-overflow (which correctly changes signed
overflow from being "undefined" to being explicitly "wrap around").
Compilers are adjusting their sanitizers to trap wrap-around and to
detecting common code patterns that should not be instrumented
(e.g. "var + offset < var"). Prepare for this and explicitly rename
the option from "OVERFLOW" to "WRAP" to more accurately describe the
behavior.
To annotate intentional wrap-around arithmetic, the helpers
wrapping_add/sub/mul_wrap() can be used for individual statements. At
the function level, the __signed_wrap attribute can be used to mark an
entire function as expecting its signed arithmetic to wrap around. For a
single object file the Makefile can use "UBSAN_SIGNED_WRAP_target.o := n"
to mark it as wrapping, and for an entire directory, "UBSAN_SIGNED_WRAP :=
n" can be used.
Additionally keep these disabled under CONFIG_COMPILE_TEST for now.
Link: https://github.com/KSPP/linux/issues/26 [1]
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Hao Luo <haoluo@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Justin Stitt <justinstitt@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
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In commit 4356e9f841f7 ("work around gcc bugs with 'asm goto' with
outputs") I did the gcc workaround unconditionally, because the cause of
the bad code generation wasn't entirely clear.
In the meantime, Jakub Jelinek debugged the issue, and has come up with
a fix in gcc [2], which also got backported to the still maintained
branches of gcc-11, gcc-12 and gcc-13.
Note that while the fix technically wasn't in the original gcc-14
branch, Jakub says:
"while it is true that no GCC 14 snapshots until today (or whenever the
fix will be committed) have the fix, for GCC trunk it is up to the
distros to use the latest snapshot if they use it at all and would
allow better testing of the kernel code without the workaround, so
that if there are other issues they won't be discovered years later.
Most userland code doesn't actually use asm goto with outputs..."
so we will consider gcc-14 to be fixed - if somebody is using gcc
snapshots of the gcc-14 before the fix, they should upgrade.
Note that while the bug goes back to gcc-11, in practice other gcc
changes seem to have effectively hidden it since gcc-12.1 as per a
bisect by Jakub. So even a gcc-14 snapshot without the fix likely
doesn't show actual problems.
Also, make the default 'asm_goto_output()' macro mark the asm as
volatile by hand, because of an unrelated gcc issue [1] where it doesn't
match the documented behavior ("asm goto is always volatile").
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103979 [1]
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113921 [2]
Link: https://lore.kernel.org/all/20240208220604.140859-1-seanjc@google.com/
Requested-by: Jakub Jelinek <jakub@redhat.com>
Cc: Uros Bizjak <ubizjak@gmail.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Andrew Pinski <quic_apinski@quicinc.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
We've had issues with gcc and 'asm goto' before, and we created a
'asm_volatile_goto()' macro for that in the past: see commits
3f0116c3238a ("compiler/gcc4: Add quirk for 'asm goto' miscompilation
bug") and a9f180345f53 ("compiler/gcc4: Make quirk for
asm_volatile_goto() unconditional").
Then, much later, we ended up removing the workaround in commit
43c249ea0b1e ("compiler-gcc.h: remove ancient workaround for gcc PR
58670") because we no longer supported building the kernel with the
affected gcc versions, but we left the macro uses around.
Now, Sean Christopherson reports a new version of a very similar
problem, which is fixed by re-applying that ancient workaround. But the
problem in question is limited to only the 'asm goto with outputs'
cases, so instead of re-introducing the old workaround as-is, let's
rename and limit the workaround to just that much less common case.
It looks like there are at least two separate issues that all hit in
this area:
(a) some versions of gcc don't mark the asm goto as 'volatile' when it
has outputs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98619
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110420
which is easy to work around by just adding the 'volatile' by hand.
(b) Internal compiler errors:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110422
which are worked around by adding the extra empty 'asm' as a
barrier, as in the original workaround.
but the problem Sean sees may be a third thing since it involves bad
code generation (not an ICE) even with the manually added 'volatile'.
but the same old workaround works for this case, even if this feels a
bit like voodoo programming and may only be hiding the issue.
Reported-and-tested-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/all/20240208220604.140859-1-seanjc@google.com/
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Uros Bizjak <ubizjak@gmail.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Andrew Pinski <quic_apinski@quicinc.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Add DEFINE_FLEX() macro for on-stack allocations of structs with
flexible array member.
Expose __struct_size() macro outside of fortify-string.h, as it could be
used to read size of structs allocated by DEFINE_FLEX().
Move __member_size() alongside it.
-Kees
Using underlying array for on-stack storage lets us to declare
known-at-compile-time structures without kzalloc().
Actual usage for ice driver is in following patches of the series.
Missing __has_builtin() workaround is moved up to serve also assembly
compilation with m68k-linux-gcc, see [1].
Error was (note the .S file extension):
In file included from ../include/linux/linkage.h:5,
from ../arch/m68k/fpsp040/skeleton.S:40:
../include/linux/compiler_types.h:331:5: warning: "__has_builtin" is not defined, evaluates to 0 [-Wundef]
331 | #if __has_builtin(__builtin_dynamic_object_size)
| ^~~~~~~~~~~~~
../include/linux/compiler_types.h:331:18: error: missing binary operator before token "("
331 | #if __has_builtin(__builtin_dynamic_object_size)
| ^
[1] https://lore.kernel.org/netdev/202308112122.OuF0YZqL-lkp@intel.com/
Co-developed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Link: https://lore.kernel.org/r/20230912115937.1645707-2-przemyslaw.kitszel@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
[1]: "On X86-64 and AArch64 targets, this attribute changes the calling
convention of a function. The preserve_most calling convention attempts
to make the code in the caller as unintrusive as possible. This
convention behaves identically to the C calling convention on how
arguments and return values are passed, but it uses a different set of
caller/callee-saved registers. This alleviates the burden of saving and
recovering a large register set before and after the call in the caller.
If the arguments are passed in callee-saved registers, then they will be
preserved by the callee across the call. This doesn't apply for values
returned in callee-saved registers.
* On X86-64 the callee preserves all general purpose registers, except
for R11. R11 can be used as a scratch register. Floating-point
registers (XMMs/YMMs) are not preserved and need to be saved by the
caller.
* On AArch64 the callee preserve all general purpose registers, except
x0-X8 and X16-X18."
[1] https://clang.llvm.org/docs/AttributeReference.html#preserve-most
Introduce the attribute to compiler_types.h as __preserve_most.
Use of this attribute results in better code generation for calls to
very rarely called functions, such as error-reporting functions, or
rarely executed slow paths.
Beware that the attribute conflicts with instrumentation calls inserted
on function entry which do not use __preserve_most themselves. Notably,
function tracing which assumes the normal C calling convention for the
given architecture. Where the attribute is supported, __preserve_most
will imply notrace. It is recommended to restrict use of the attribute
to functions that should or already disable tracing.
Note: The additional preprocessor check against architecture should not
be necessary if __has_attribute() only returns true where supported;
also see https://github.com/ClangBuiltLinux/linux/issues/1908. But until
__has_attribute() does the right thing, we also guard by known-supported
architectures to avoid build warnings on other architectures.
The attribute may be supported by a future GCC version (see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110899).
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20230811151847.1594958-1-elver@google.com
Signed-off-by: Kees Cook <keescook@chromium.org>
|
|
include/linux/compiler-intel.h had no update in the past 3 years.
We often forget about the third C compiler to build the kernel.
For example, commit a0a12c3ed057 ("asm goto: eradicate CC_HAS_ASM_GOTO")
only mentioned GCC and Clang.
init/Kconfig defines CC_IS_GCC and CC_IS_CLANG but not CC_IS_ICC,
and nobody has reported any issue.
I guess the Intel Compiler support is broken, and nobody is caring
about it.
Harald Arnesen pointed out ICC (classic Intel C/C++ compiler) is
deprecated:
$ icc -v
icc: remark #10441: The Intel(R) C++ Compiler Classic (ICC) is
deprecated and will be removed from product release in the second half
of 2023. The Intel(R) oneAPI DPC++/C++ Compiler (ICX) is the recommended
compiler moving forward. Please transition to use this compiler. Use
'-diag-disable=10441' to disable this message.
icc version 2021.7.0 (gcc version 12.1.0 compatibility)
Arnd Bergmann provided a link to the article, "Intel C/C++ compilers
complete adoption of LLVM".
lib/zstd/common/compiler.h and lib/zstd/compress/zstd_fast.c were kept
untouched for better sync with https://github.com/facebook/zstd
Link: https://www.intel.com/content/www/us/en/developer/articles/technical/adoption-of-llvm-complete-icx.html
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas:
- Support for arm64 SME 2 and 2.1. SME2 introduces a new 512-bit
architectural register (ZT0, for the look-up table feature) that
Linux needs to save/restore
- Include TPIDR2 in the signal context and add the corresponding
kselftests
- Perf updates: Arm SPEv1.2 support, HiSilicon uncore PMU updates, ACPI
support to the Marvell DDR and TAD PMU drivers, reset DTM_PMU_CONFIG
(ARM CMN) at probe time
- Support for DYNAMIC_FTRACE_WITH_CALL_OPS on arm64
- Permit EFI boot with MMU and caches on. Instead of cleaning the
entire loaded kernel image to the PoC and disabling the MMU and
caches before branching to the kernel bare metal entry point, leave
the MMU and caches enabled and rely on EFI's cacheable 1:1 mapping of
all of system RAM to populate the initial page tables
- Expose the AArch32 (compat) ELF_HWCAP features to user in an arm64
kernel (the arm32 kernel only defines the values)
- Harden the arm64 shadow call stack pointer handling: stash the shadow
stack pointer in the task struct on interrupt, load it directly from
this structure
- Signal handling cleanups to remove redundant validation of size
information and avoid reading the same data from userspace twice
- Refactor the hwcap macros to make use of the automatically generated
ID registers. It should make new hwcaps writing less error prone
- Further arm64 sysreg conversion and some fixes
- arm64 kselftest fixes and improvements
- Pointer authentication cleanups: don't sign leaf functions, unify
asm-arch manipulation
- Pseudo-NMI code generation optimisations
- Minor fixes for SME and TPIDR2 handling
- Miscellaneous updates: ARCH_FORCE_MAX_ORDER is now selectable,
replace strtobool() to kstrtobool() in the cpufeature.c code, apply
dynamic shadow call stack in two passes, intercept pfn changes in
set_pte_at() without the required break-before-make sequence, attempt
to dump all instructions on unhandled kernel faults
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (130 commits)
arm64: fix .idmap.text assertion for large kernels
kselftest/arm64: Don't require FA64 for streaming SVE+ZA tests
kselftest/arm64: Copy whole EXTRA context
arm64: kprobes: Drop ID map text from kprobes blacklist
perf: arm_spe: Print the version of SPE detected
perf: arm_spe: Add support for SPEv1.2 inverted event filtering
perf: Add perf_event_attr::config3
arm64/sme: Fix __finalise_el2 SMEver check
drivers/perf: fsl_imx8_ddr_perf: Remove set-but-not-used variable
arm64/signal: Only read new data when parsing the ZT context
arm64/signal: Only read new data when parsing the ZA context
arm64/signal: Only read new data when parsing the SVE context
arm64/signal: Avoid rereading context frame sizes
arm64/signal: Make interface for restore_fpsimd_context() consistent
arm64/signal: Remove redundant size validation from parse_user_sigframe()
arm64/signal: Don't redundantly verify FPSIMD magic
arm64/cpufeature: Use helper macros to specify hwcaps
arm64/cpufeature: Always use symbolic name for feature value in hwcaps
arm64/sysreg: Initial unsigned annotations for ID registers
arm64/sysreg: Initial annotation of signed ID registers
...
|
|
Contemporary versions of GCC (e.g. GCC 12.2.0) drop the alignment
specified by '-falign-functions=N' for functions marked with the
__cold__ attribute, and potentially for callees of __cold__ functions as
these may be implicitly marked as __cold__ by the compiler. LLVM appears
to respect '-falign-functions=N' in such cases.
This has been reported to GCC in bug 88345:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88345
... which also covers alignment being dropped when '-Os' is used, which
will be addressed in a separate patch.
Currently, use of '-falign-functions=N' is limited to
CONFIG_FUNCTION_ALIGNMENT, which is largely used for performance and/or
analysis reasons (e.g. with CONFIG_DEBUG_FORCE_FUNCTION_ALIGN_64B), but
isn't necessary for correct functionality. However, this dropped
alignment isn't great for the performance and/or analysis cases.
Subsequent patches will use CONFIG_FUNCTION_ALIGNMENT as part of arm64's
ftrace implementation, which will require all instrumented functions to
be aligned to at least 8-bytes.
This patch works around the dropped alignment by avoiding the use of the
__cold__ attribute when CONFIG_FUNCTION_ALIGNMENT is non-zero, and by
specifically aligning abort(), which GCC implicitly marks as __cold__.
As the __cold macro is now dependent upon config options (which is
against the policy described at the top of compiler_attributes.h), it is
moved into compiler_types.h.
I've tested this by building and booting a kernel configured with
defconfig + CONFIG_EXPERT=y + CONFIG_DEBUG_FORCE_FUNCTION_ALIGN_64B=y,
and looking for misaligned text symbols in /proc/kallsyms:
* arm64:
Before:
# uname -rm
6.2.0-rc3 aarch64
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
5009
After:
# uname -rm
6.2.0-rc3-00001-g2a2bedf8bfa9 aarch64
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
919
* x86_64:
Before:
# uname -rm
6.2.0-rc3 x86_64
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
11537
After:
# uname -rm
6.2.0-rc3-00001-g2a2bedf8bfa9 x86_64
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
2805
There's clearly a substantial reduction in the number of misaligned
symbols. From manual inspection, the remaining unaligned text labels are
a combination of ACPICA functions (due to the use of '-Os'), static call
trampolines, and non-function labels in assembly, which will be dealt
with in subsequent patches.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Deacon <will@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20230123134603.1064407-3-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
|
|
Add a few words on noinstr / __cpuidle usage.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230112195542.397238052@infradead.org
|
|
Idle code is very like entry code in that RCU isn't available. As
such, add a little validation.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230112195540.373461409@infradead.org
|
|
Currently, without rcu attribute info in BTF, the verifier treats
rcu tagged pointer as a normal pointer. This might be a problem
for sleepable program where rcu_read_lock()/unlock() is not available.
For example, for a sleepable fentry program, if rcu protected memory
access is interleaved with a sleepable helper/kfunc, it is possible
the memory access after the sleepable helper/kfunc might be invalid
since the object might have been freed then. To prevent such cases,
introducing rcu tagging for memory accesses in verifier can help
to reject such programs.
To enable rcu tagging in BTF, during kernel compilation,
define __rcu as attribute btf_type_tag("rcu") so __rcu information can
be preserved in dwarf and btf, and later can be used for bpf prog verification.
Acked-by: KP Singh <kpsingh@kernel.org>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221124053206.2373141-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Yu Zhao's Multi-Gen LRU patches are here. They've been under test in
linux-next for a couple of months without, to my knowledge, any
negative reports (or any positive ones, come to that).
- Also the Maple Tree from Liam Howlett. An overlapping range-based
tree for vmas. It it apparently slightly more efficient in its own
right, but is mainly targeted at enabling work to reduce mmap_lock
contention.
Liam has identified a number of other tree users in the kernel which
could be beneficially onverted to mapletrees.
Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat
at [1]. This has yet to be addressed due to Liam's unfortunately
timed vacation. He is now back and we'll get this fixed up.
- Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses
clang-generated instrumentation to detect used-unintialized bugs down
to the single bit level.
KMSAN keeps finding bugs. New ones, as well as the legacy ones.
- Yang Shi adds a userspace mechanism (madvise) to induce a collapse of
memory into THPs.
- Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to
support file/shmem-backed pages.
- userfaultfd updates from Axel Rasmussen
- zsmalloc cleanups from Alexey Romanov
- cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and
memory-failure
- Huang Ying adds enhancements to NUMA balancing memory tiering mode's
page promotion, with a new way of detecting hot pages.
- memcg updates from Shakeel Butt: charging optimizations and reduced
memory consumption.
- memcg cleanups from Kairui Song.
- memcg fixes and cleanups from Johannes Weiner.
- Vishal Moola provides more folio conversions
- Zhang Yi removed ll_rw_block() :(
- migration enhancements from Peter Xu
- migration error-path bugfixes from Huang Ying
- Aneesh Kumar added ability for a device driver to alter the memory
tiering promotion paths. For optimizations by PMEM drivers, DRM
drivers, etc.
- vma merging improvements from Jakub Matěn.
- NUMA hinting cleanups from David Hildenbrand.
- xu xin added aditional userspace visibility into KSM merging
activity.
- THP & KSM code consolidation from Qi Zheng.
- more folio work from Matthew Wilcox.
- KASAN updates from Andrey Konovalov.
- DAMON cleanups from Kaixu Xia.
- DAMON work from SeongJae Park: fixes, cleanups.
- hugetlb sysfs cleanups from Muchun Song.
- Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core.
Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1]
* tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits)
hugetlb: allocate vma lock for all sharable vmas
hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer
hugetlb: fix vma lock handling during split vma and range unmapping
mglru: mm/vmscan.c: fix imprecise comments
mm/mglru: don't sync disk for each aging cycle
mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol
mm: memcontrol: use do_memsw_account() in a few more places
mm: memcontrol: deprecate swapaccounting=0 mode
mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled
mm/secretmem: remove reduntant return value
mm/hugetlb: add available_huge_pages() func
mm: remove unused inline functions from include/linux/mm_inline.h
selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory
selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd
selftests/vm: add thp collapse shmem testing
selftests/vm: add thp collapse file and tmpfs testing
selftests/vm: modularize thp collapse memory operations
selftests/vm: dedup THP helpers
mm/khugepaged: add tracepoint to hpage_collapse_scan_file()
mm/madvise: add file and shmem support to MADV_COLLAPSE
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab
Pull slab fixes from Vlastimil Babka:
- The "common kmalloc v4" series [1] by Hyeonggon Yoo.
While the plan after LPC is to try again if it's possible to get rid
of SLOB and SLAB (and if any critical aspect of those is not possible
to achieve with SLUB today, modify it accordingly), it will take a
while even in case there are no objections.
Meanwhile this is a nice cleanup and some parts (e.g. to the
tracepoints) will be useful even if we end up with a single slab
implementation in the future:
- Improves the mm/slab_common.c wrappers to allow deleting
duplicated code between SLAB and SLUB.
- Large kmalloc() allocations in SLAB are passed to page allocator
like in SLUB, reducing number of kmalloc caches.
- Removes the {kmem_cache_alloc,kmalloc}_node variants of
tracepoints, node id parameter added to non-_node variants.
- Addition of kmalloc_size_roundup()
The first two patches from a series by Kees Cook [2] that introduce
kmalloc_size_roundup(). This will allow merging of per-subsystem
patches using the new function |
