Allow a struct_ops program to return a referenced kptr if the struct_ops
operator's return type is a struct pointer. To make sure the returned
pointer continues to be valid in the kernel, several constraints are
required:
1) The type of the pointer must matches the return type
2) The pointer originally comes from the kernel (not locally allocated)
3) The pointer is in its unmodified form
Implementation wise, a referenced kptr first needs to be allowed to _leak_
in check_reference_leak() if it is in the return register. Then, in
check_return_code(), constraints 1-3 are checked. During struct_ops
registration, a check is also added to warn about operators with
non-struct pointer return.
In addition, since the first user, Qdisc_ops::dequeue, allows a NULL
pointer to be returned when there is no skb to be dequeued, we will allow
a scalar value with value equals to NULL to be returned.
In the future when there is a struct_ops user that always expects a valid
pointer to be returned from an operator, we may extend tagging to the
return value. We can tell the verifier to only allow NULL pointer return
if the return value is tagged with MAY_BE_NULL.
Signed-off-by: Amery Hung <amery.hung@bytedance.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20250217190640.1748177-5-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Allows struct_ops programs to acqurie referenced kptrs from arguments
by directly reading the argument.
The verifier will acquire a reference for struct_ops a argument tagged
with "__ref" in the stub function in the beginning of the main program.
The user will be able to access the referenced kptr directly by reading
the context as long as it has not been released by the program.
This new mechanism to acquire referenced kptr (compared to the existing
"kfunc with KF_ACQUIRE") is introduced for ergonomic and semantic reasons.
In the first use case, Qdisc_ops, an skb is passed to .enqueue in the
first argument. This mechanism provides a natural way for users to get a
referenced kptr in the .enqueue struct_ops programs and makes sure that a
qdisc will always enqueue or drop the skb.
Signed-off-by: Amery Hung <amery.hung@bytedance.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20250217190640.1748177-3-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, ctx_arg_info is read-only in the view of the verifier since
it is shared among programs of the same attach type. Make each program
have their own copy of ctx_arg_info so that we can use it to store
program specific information.
In the next patch where we support acquiring a referenced kptr through a
struct_ops argument tagged with "__ref", ctx_arg_info->ref_obj_id will
be used to store the unique reference object id of the argument. This
avoids creating a requirement in the verifier that "__ref" tagged
arguments must be the first set of references acquired [0].
[0] https://lore.kernel.org/bpf/20241220195619.2022866-2-amery.hung@gmail.com/
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20250217190640.1748177-2-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
may_goto uses an additional 8 bytes on the stack, which causes the
interpreters[] array to go out of bounds when calculating index by
stack_size.
1. If a BPF program is rewritten, re-evaluate the stack size. For non-JIT
cases, reject loading directly.
2. For non-JIT cases, calculating interpreters[idx] may still cause
out-of-bounds array access, and just warn about it.
3. For jit_requested cases, the execution of bpf_func also needs to be
warned. So move the definition of function __bpf_prog_ret0_warn out of
the macro definition CONFIG_BPF_JIT_ALWAYS_ON.
Reported-by: syzbot+d2a2c639d03ac200a4f1@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/0000000000000f823606139faa5d@google.com/
Fixes: 011832b97b ("bpf: Introduce may_goto instruction")
Signed-off-by: Jiayuan Chen <mrpre@163.com>
Link: https://lore.kernel.org/r/20250214091823.46042-2-mrpre@163.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add the following kfuncs to set and remove xattrs from BPF programs:
bpf_set_dentry_xattr
bpf_remove_dentry_xattr
bpf_set_dentry_xattr_locked
bpf_remove_dentry_xattr_locked
The _locked version of these kfuncs are called from hooks where
dentry->d_inode is already locked. Instead of requiring the user
to know which version of the kfuncs to use, the verifier will pick
the proper kfunc based on the calling hook.
Signed-off-by: Song Liu <song@kernel.org>
Acked-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Matt Bobrowski <mattbobrowski@google.com>
Link: https://lore.kernel.org/r/20250130213549.3353349-5-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf_arena_alloc_pages() and bpf_arena_free_pages() work with the
bpf_arena pointers [1], which is indicated by the __arena macro in the
kernel source code:
#define __arena __attribute__((address_space(1)))
However currently this information is absent from the debug data in
the vmlinux binary. As a consequence, bpf_arena_* kfuncs declarations
in vmlinux.h (produced by bpftool) do not match prototypes expected by
the BPF programs attempting to use these functions.
Introduce a set of kfunc flags to mark relevant types as bpf_arena
pointers. The flags then can be detected by pahole when generating BTF
from vmlinux's DWARF, allowing it to emit corresponding BTF type tags
for the marked kfuncs.
With recently proposed BTF extension [2], these type tags will be
processed by bpftool when dumping vmlinux.h, and corresponding
compiler attributes will be added to the declarations.
[1] https://lwn.net/Articles/961594/
[2] https://lore.kernel.org/bpf/20250130201239.1429648-1-ihor.solodrai@linux.dev/
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://lore.kernel.org/r/20250206003148.2308659-1-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
BTF type tags and decl tags now may have info->kflag set to 1,
changing the semantics of the tag.
Change BTF verification to permit BTF that makes use of this feature:
* remove kflag check in btf_decl_tag_check_meta(), as both values
are valid
* allow kflag to be set for BTF_KIND_TYPE_TAG type in
btf_ref_type_check_meta()
Make sure kind_flag is NOT set when checking for specific BTF tags,
such as "kptr", "user" etc.
Modify a selftest checking for kflag in decl_tag accordingly.
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20250130201239.1429648-6-ihor.solodrai@linux.dev
In commit 1611603537 ("bpf: Create argument information for nullable arguments."),
it introduced a "__nullable" tagging at the argument name of a
stub function. Some background on the commit:
it requires to tag the stub function instead of directly tagging
the "ops" of a struct. This is because the btf func_proto of the "ops"
does not have the argument name and the "__nullable" is tagged at
the argument name.
To find the stub function of a "ops", it currently relies on a naming
convention on the stub function "st_ops__ops_name".
e.g. tcp_congestion_ops__ssthresh. However, the new kernel
sub system implementing bpf_struct_ops have missed this and
have been surprised that the "__nullable" and the to-be-landed
"__ref" tagging was not effective.
One option would be to give a warning whenever the stub function does
not follow the naming convention, regardless if it requires arg tagging
or not.
Instead, this patch uses the kallsyms_lookup approach and removes
the requirement on the naming convention. The st_ops->cfi_stubs has
all the stub function kernel addresses. kallsyms_lookup() is used to
lookup the function name. With the function name, BTF can be used to
find the BTF func_proto. The existing "__nullable" arg name searching
logic will then fall through.
One notable change is,
if it failed in kallsyms_lookup or it failed in looking up the stub
function name from the BTF, the bpf_struct_ops registration will fail.
This is different from the previous behavior that it silently ignored
the "st_ops__ops_name" function not found error.
The "tcp_congestion_ops", "sched_ext_ops", and "hid_bpf_ops" can still be
registered successfully after this patch. There is struct_ops_maybe_null
selftest to cover the "__nullable" tagging.
Other minor changes:
1. Removed the "%s__%s" format from the pr_warn because the naming
convention is removed.
2. The existing bpf_struct_ops_supported() is also moved earlier
because prepare_arg_info needs to use it to decide if the
stub function is NULL before calling the prepare_arg_info.
Cc: Tejun Heo <tj@kernel.org>
Cc: Benjamin Tissoires <bentiss@kernel.org>
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Reviewed-by: Amery Hung <ameryhung@gmail.com>
Link: https://lore.kernel.org/r/20250127222719.2544255-1-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Pull misc fixes from Andrew Morton:
"21 hotfixes. 8 are cc:stable and the remainder address post-6.13
issues. 13 are for MM and 8 are for non-MM.
All are singletons, please see the changelogs for details"
* tag 'mm-hotfixes-stable-2025-02-01-03-56' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (21 commits)
MAINTAINERS: include linux-mm for xarray maintenance
revert "xarray: port tests to kunit"
MAINTAINERS: add lib/test_xarray.c
mailmap, MAINTAINERS, docs: update Carlos's email address
mm/hugetlb: fix hugepage allocation for interleaved memory nodes
mm: gup: fix infinite loop within __get_longterm_locked
mm, swap: fix reclaim offset calculation error during allocation
.mailmap: update email address for Christopher Obbard
kfence: skip __GFP_THISNODE allocations on NUMA systems
nilfs2: fix possible int overflows in nilfs_fiemap()
mm: compaction: use the proper flag to determine watermarks
kernel: be more careful about dup_mmap() failures and uprobe registering
mm/fake-numa: handle cases with no SRAT info
mm: kmemleak: fix upper boundary check for physical address objects
mailmap: add an entry for Hamza Mahfooz
MAINTAINERS: mailmap: update Yosry Ahmed's email address
scripts/gdb: fix aarch64 userspace detection in get_current_task
mm/vmscan: accumulate nr_demoted for accurate demotion statistics
ocfs2: fix incorrect CPU endianness conversion causing mount failure
mm/zsmalloc: add __maybe_unused attribute for is_first_zpdesc()
...
If a memory allocation fails during dup_mmap(), the maple tree can be left
in an unsafe state for other iterators besides the exit path. All the
locks are dropped before the exit_mmap() call (in mm/mmap.c), but the
incomplete mm_struct can be reached through (at least) the rmap finding
the vmas which have a pointer back to the mm_struct.
Up to this point, there have been no issues with being able to find an
mm_struct that was only partially initialised. Syzbot was able to make
the incomplete mm_struct fail with recent forking changes, so it has been
proven unsafe to use the mm_struct that hasn't been initialised, as
referenced in the link below.
Although 8ac662f5da ("fork: avoid inappropriate uprobe access to
invalid mm") fixed the uprobe access, it does not completely remove the
race.
This patch sets the MMF_OOM_SKIP to avoid the iteration of the vmas on the
oom side (even though this is extremely unlikely to be selected as an oom
victim in the race window), and sets MMF_UNSTABLE to avoid other potential
users from using a partially initialised mm_struct.
When registering vmas for uprobe, skip the vmas in an mm that is marked
unstable. Modifying a vma in an unstable mm may cause issues if the mm
isn't fully initialised.
Link: https://lore.kernel.org/all/6756d273.050a0220.2477f.003d.GAE@google.com/
Link: https://lkml.kernel.org/r/20250127170221.1761366-1-Liam.Howlett@oracle.com
Fixes: d240629148 ("fork: use __mt_dup() to duplicate maple tree in dup_mmap()")
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull Kbuild updates from Masahiro Yamada:
- Support multiple hook locations for maint scripts of Debian package
- Remove 'cpio' from the build tool requirement
- Introduce gendwarfksyms tool, which computes CRCs for export symbols
based on the DWARF information
- Support CONFIG_MODVERSIONS for Rust
- Resolve all conflicts in the genksyms parser
- Fix several syntax errors in genksyms
* tag 'kbuild-v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (64 commits)
kbuild: fix Clang LTO with CONFIG_OBJTOOL=n
kbuild: Strip runtime const RELA sections correctly
kconfig: fix memory leak in sym_warn_unmet_dep()
kconfig: fix file name in warnings when loading KCONFIG_DEFCONFIG_LIST
genksyms: fix syntax error for attribute before init-declarator
genksyms: fix syntax error for builtin (u)int*x*_t types
genksyms: fix syntax error for attribute after 'union'
genksyms: fix syntax error for attribute after 'struct'
genksyms: fix syntax error for attribute after abstact_declarator
genksyms: fix syntax error for attribute before nested_declarator
genksyms: fix syntax error for attribute before abstract_declarator
genksyms: decouple ATTRIBUTE_PHRASE from type-qualifier
genksyms: record attributes consistently for init-declarator
genksyms: restrict direct-declarator to take one parameter-type-list
genksyms: restrict direct-abstract-declarator to take one parameter-type-list
genksyms: remove Makefile hack
genksyms: fix last 3 shift/reduce conflicts
genksyms: fix 6 shift/reduce conflicts and 5 reduce/reduce conflicts
genksyms: reduce type_qualifier directly to decl_specifier
genksyms: rename cvar_qualifier to type_qualifier
...
Pull audit fix from Paul Moore:
"A minor audit patch to fix an unitialized variable problem"
* tag 'audit-pr-20250130' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
audit: Initialize lsmctx to avoid memory allocation error
Pull more power management updates from Rafael Wysocki:
"These are mostly fixes on top of the previously merged power
management material with the addition of some teo cpuidle governor
updates, some of which may also be regarded as fixes:
- Add missing error handling for syscore_suspend() to the hibernation
core code (Wentao Liang)
- Revert a commit that added unused macros (Andy Shevchenko)
- Synchronize the runtime PM status of devices that were runtime-
suspended before a system-wide suspend and need to be resumed
during the subsequent system-wide resume transition (Rafael
Wysocki)
- Clean up the teo cpuidle governor and make the handling of short
idle intervals in it consistent regardless of the properties of
idle states supplied by the cpuidle driver (Rafael Wysocki)
- Fix some boost-related issues in cpufreq (Lifeng Zheng)
- Fix build issues in the s3c64xx and airoha cpufreq drivers (Viresh
Kumar)
- Remove unconditional binding of schedutil governor kthreads to the
affected CPUs if the cpufreq driver indicates that updates can
happen from any CPU (Christian Loehle)"
* tag 'pm-6.14-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
PM: sleep: core: Synchronize runtime PM status of parents and children
cpufreq: airoha: Depends on OF
PM: Revert "Add EXPORT macros for exporting PM functions"
PM: hibernate: Add error handling for syscore_suspend()
cpufreq/schedutil: Only bind threads if needed
cpufreq: ACPI: Remove set_boost in acpi_cpufreq_cpu_init()
cpufreq: CPPC: Fix wrong max_freq in policy initialization
cpufreq: Introduce a more generic way to set default per-policy boost flag
cpufreq: Fix re-boost issue after hotplugging a CPU
cpufreq: s3c64xx: Fix compilation warning
cpuidle: teo: Skip sleep length computation for low latency constraints
cpuidle: teo: Replace time_span_ns with a flag
cpuidle: teo: Simplify handling of total events count
cpuidle: teo: Skip getting the sleep length if wakeups are very frequent
cpuidle: teo: Simplify counting events used for tick management
cpuidle: teo: Clarify two code comments
cpuidle: teo: Drop local variable prev_intercept_idx
cpuidle: teo: Combine candidate state index checks against 0
cpuidle: teo: Reorder candidate state index checks
cpuidle: teo: Rearrange idle state lookup code
Merge fixes related to system sleep for 6.14-rc1:
- Add missing error handling for syscore_suspend() to the hibernation
core code (Wentao Liang).
- Revert a commit that added unused macros (Andy Shevchenko).
- Synchronize the runtime PM status of devices that were runtime-
suspended before a system-wide suspend and need to be resumed during
the subsequent syste-wide resume transition (Rafael Wysocki).
* pm-sleep:
PM: sleep: core: Synchronize runtime PM status of parents and children
PM: Revert "Add EXPORT macros for exporting PM functions"
PM: hibernate: Add error handling for syscore_suspend()
When audit is enabled in a kernel build, and there are no LSMs active
that support LSM labeling, it is possible that local variable lsmctx
in the AUDIT_SIGNAL_INFO handler in audit_receive_msg() could be used
before it is properly initialize. Then kmalloc() will try to allocate
a large amount of memory with the uninitialized length.
This patch corrects this problem by initializing the lsmctx to a safe
value when it is declared, which avoid errors like:
WARNING: CPU: 2 PID: 443 at mm/page_alloc.c:4727 __alloc_pages_noprof
...
ra: 9000000003059644 ___kmalloc_large_node+0x84/0x1e0
ERA: 900000000304d588 __alloc_pages_noprof+0x4c8/0x1040
CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE)
PRMD: 00000004 (PPLV0 +PIE -PWE)
EUEN: 00000007 (+FPE +SXE +ASXE -BTE)
ECFG: 00071c1d (LIE=0,2-4,10-12 VS=7)
ESTAT: 000c0000 [BRK] (IS= ECode=12 EsubCode=0)
PRID: 0014c010 (Loongson-64bit, Loongson-3A5000)
CPU: 2 UID: 0 PID: 443 Comm: auditd Not tainted 6.13.0-rc1+ #1899
...
Call Trace:
[<9000000002def6a8>] show_stack+0x30/0x148
[<9000000002debf58>] dump_stack_lvl+0x68/0xa0
[<9000000002e0fe18>] __warn+0x80/0x108
[<900000000407486c>] report_bug+0x154/0x268
[<90000000040ad468>] do_bp+0x2a8/0x320
[<9000000002dedda0>] handle_bp+0x120/0x1c0
[<900000000304d588>] __alloc_pages_noprof+0x4c8/0x1040
[<9000000003059640>] ___kmalloc_large_node+0x80/0x1e0
[<9000000003061504>] __kmalloc_noprof+0x2c4/0x380
[<9000000002f0f7ac>] audit_receive_msg+0x764/0x1530
[<9000000002f1065c>] audit_receive+0xe4/0x1c0
[<9000000003e5abe8>] netlink_unicast+0x340/0x450
[<9000000003e5ae9c>] netlink_sendmsg+0x1a4/0x4a0
[<9000000003d9ffd0>] __sock_sendmsg+0x48/0x58
[<9000000003da32f0>] __sys_sendto+0x100/0x170
[<9000000003da3374>] sys_sendto+0x14/0x28
[<90000000040ad574>] do_syscall+0x94/0x138
[<9000000002ded318>] handle_syscall+0xb8/0x158
Fixes: 6fba89813c ("lsm: ensure the correct LSM context releaser")
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
[PM: resolved excessive line length in the backtrace]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pull sysctl table constification from Joel Granados:
"All ctl_table declared outside of functions and that remain unmodified
after initialization are const qualified.
This prevents unintended modifications to proc_handler function
pointers by placing them in the .rodata section.
This is a continuation of the tree-wide effort started a few releases
ago with the constification of the ctl_table struct arguments in the
sysctl API done in 78eb4ea25c ("sysctl: treewide: constify the
ctl_table argument of proc_handlers")"
* tag 'constfy-sysctl-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl:
treewide: const qualify ctl_tables where applicable
Pull driver core and debugfs updates from Greg KH:
"Here is the big set of driver core and debugfs updates for 6.14-rc1.
Included in here is a bunch of driver core, PCI, OF, and platform rust
bindings (all acked by the different subsystem maintainers), hence the
merge conflict with the rust tree, and some driver core api updates to
mark things as const, which will also require some fixups due to new
stuff coming in through other trees in this merge window.
There are also a bunch of debugfs updates from Al, and there is at
least one user that does have a regression with these, but Al is
working on tracking down the fix for it. In my use (and everyone
else's linux-next use), it does not seem like a big issue at the
moment.
Here's a short list of the things in here:
- driver core rust bindings for PCI, platform, OF, and some i/o
functions.
We are almost at the "write a real driver in rust" stage now,
depending on what you want to do.
- misc device rust bindings and a sample driver to show how to use
them
- debugfs cleanups in the fs as well as the users of the fs api for
places where drivers got it wrong or were unnecessarily doing
things in complex ways.
- driver core const work, making more of the api take const * for
different parameters to make the rust bindings easier overall.
- other small fixes and updates
All of these have been in linux-next with all of the aforementioned
merge conflicts, and the one debugfs issue, which looks to be resolved
"soon""
* tag 'driver-core-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (95 commits)
rust: device: Use as_char_ptr() to avoid explicit cast
rust: device: Replace CString with CStr in property_present()
devcoredump: Constify 'struct bin_attribute'
devcoredump: Define 'struct bin_attribute' through macro
rust: device: Add property_present()
saner replacement for debugfs_rename()
orangefs-debugfs: don't mess with ->d_name
octeontx2: don't mess with ->d_parent or ->d_parent->d_name
arm_scmi: don't mess with ->d_parent->d_name
slub: don't mess with ->d_name
sof-client-ipc-flood-test: don't mess with ->d_name
qat: don't mess with ->d_name
xhci: don't mess with ->d_iname
mtu3: don't mess wiht ->d_iname
greybus/camera - stop messing with ->d_iname
mediatek: stop messing with ->d_iname
netdevsim: don't embed file_operations into your structs
b43legacy: make use of debugfs_get_aux()
b43: stop embedding struct file_operations into their objects
carl9170: stop embedding file_operations into their objects
...
Pull stop_machine update from Paul McKenney:
"Move a misplaced call to rcu_momentary_eqs() from multi_cpu_stop() to
ensure that interrupts are disabled as required"
* tag 'stop-machine.2025.01.28a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
stop_machine: Fix rcu_momentary_eqs() call in multi_cpu_stop()
Pull CSD-lock update from Paul McKenney:
"Allow runtime modification of the csd_lock_timeout and
panic_on_ipistall module parameters"
* tag 'csd-lock.2025.01.28a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
locking/csd-lock: make CSD lock debug tunables writable in /sys
Add the const qualifier to all the ctl_tables in the tree except for
watchdog_hardlockup_sysctl, memory_allocation_profiling_sysctls,
loadpin_sysctl_table and the ones calling register_net_sysctl (./net,
drivers/inifiniband dirs). These are special cases as they use a
registration function with a non-const qualified ctl_table argument or
modify the arrays before passing them on to the registration function.
Constifying ctl_table structs will prevent the modification of
proc_handler function pointers as the arrays would reside in .rodata.
This is made possible after commit 78eb4ea25c ("sysctl: treewide:
constify the ctl_table argument of proc_handlers") constified all the
proc_handlers.
Created this by running an spatch followed by a sed command:
Spatch:
virtual patch
@
depends on !(file in "net")
disable optional_qualifier
@
identifier table_name != {
watchdog_hardlockup_sysctl,
iwcm_ctl_table,
ucma_ctl_table,
memory_allocation_profiling_sysctls,
loadpin_sysctl_table
};
@@
+ const
struct ctl_table table_name [] = { ... };
sed:
sed --in-place \
-e "s/struct ctl_table .table = &uts_kern/const struct ctl_table *table = \&uts_kern/" \
kernel/utsname_sysctl.c
Reviewed-by: Song Liu <song@kernel.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org> # for kernel/trace/
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> # SCSI
Reviewed-by: Darrick J. Wong <djwong@kernel.org> # xfs
Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Corey Minyard <cminyard@mvista.com>
Acked-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Bill O'Donnell <bodonnel@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Acked-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Acked-by: Anna Schumaker <anna.schumaker@oracle.com>
Signed-off-by: Joel Granados <joel.granados@kernel.org>
Pull MM updates from Andrew Morton:
"The various patchsets are summarized below. Plus of course many
indivudual patches which are described in their changelogs.
- "Allocate and free frozen pages" from Matthew Wilcox reorganizes
the page allocator so we end up with the ability to allocate and
free zero-refcount pages. So that callers (ie, slab) can avoid a
refcount inc & dec
- "Support large folios for tmpfs" from Baolin Wang teaches tmpfs to
use large folios other than PMD-sized ones
- "Fix mm/rodata_test" from Petr Tesarik performs some maintenance
and fixes for this small built-in kernel selftest
- "mas_anode_descend() related cleanup" from Wei Yang tidies up part
of the mapletree code
- "mm: fix format issues and param types" from Keren Sun implements a
few minor code cleanups
- "simplify split calculation" from Wei Yang provides a few fixes and
a test for the mapletree code
- "mm/vma: make more mmap logic userland testable" from Lorenzo
Stoakes continues the work of moving vma-related code into the
(relatively) new mm/vma.c
- "mm/page_alloc: gfp flags cleanups for alloc_contig_*()" from David
Hildenbrand cleans up and rationalizes handling of gfp flags in the
page allocator
- "readahead: Reintroduce fix for improper RA window sizing" from Jan
Kara is a second attempt at fixing a readahead window sizing issue.
It should reduce the amount of unnecessary reading
- "synchronously scan and reclaim empty user PTE pages" from Qi Zheng
addresses an issue where "huge" amounts of pte pagetables are
accumulated:
https://lore.kernel.org/lkml/cover.1718267194.git.zhengqi.arch@bytedance.com/
Qi's series addresses this windup by synchronously freeing PTE
memory within the context of madvise(MADV_DONTNEED)
- "selftest/mm: Remove warnings found by adding compiler flags" from
Muhammad Usama Anjum fixes some build warnings in the selftests
code when optional compiler warnings are enabled
- "mm: don't use __GFP_HARDWALL when migrating remote pages" from
David Hildenbrand tightens the allocator's observance of
__GFP_HARDWALL
- "pkeys kselftests improvements" from Kevin Brodsky implements
various fixes and cleanups in the MM selftests code, mainly
pertaining to the pkeys tests
- "mm/damon: add sample modules" from SeongJae Park enhances DAMON to
estimate application working set size
- "memcg/hugetlb: Rework memcg hugetlb charging" from Joshua Hahn
provides some cleanups to memcg's hugetlb charging logic
- "mm/swap_cgroup: remove global swap cgroup lock" from Kairui Song
removes the global swap cgroup lock. A speedup of 10% for a
tmpfs-based kernel build was demonstrated
- "zram: split page type read/write handling" from Sergey Senozhatsky
has several fixes and cleaups for zram in the area of
zram_write_page(). A watchdog softlockup warning was eliminated
- "move pagetable_*_dtor() to __tlb_remove_table()" from Kevin
Brodsky cleans up the pagetable destructor implementations. A rare
use-after-free race is fixed
- "mm/debug: introduce and use VM_WARN_ON_VMG()" from Lorenzo Stoakes
simplifies and cleans up the debugging code in the VMA merging
logic
- "Account page tables at all levels" from Kevin Brodsky cleans up
and regularizes the pagetable ctor/dtor handling. This results in
improvements in accounting accuracy
- "mm/damon: replace most damon_callback usages in sysfs with new
core functions" from SeongJae Park cleans up and generalizes
DAMON's sysfs file interface logic
- "mm/damon: enable page level properties based monitoring" from
SeongJae Park increases the amount of information which is
presented in response to DAMOS actions
- "mm/damon: remove DAMON debugfs interface" from SeongJae Park
removes DAMON's long-deprecated debugfs interfaces. Thus the
migration to sysfs is completed
- "mm/hugetlb: Refactor hugetlb allocation resv accounting" from
Peter Xu cleans up and generalizes the hugetlb reservation
accounting
- "mm: alloc_pages_bulk: small API refactor" from Luiz Capitulino
removes a never-used feature of the alloc_pages_bulk() interface
- "mm/damon: extend DAMOS filters for inclusion" from SeongJae Park
extends DAMOS filters to support not only exclusion (rejecting),
but also inclusion (allowing) behavior
- "Add zpdesc memory descriptor for zswap.zpool" from Alex Shi
introduces a new memory descriptor for zswap.zpool that currently
overlaps with struct page for now. This is part of the effort to
reduce the size of struct page and to enable dynamic allocation of
memory descriptors
- "mm, swap: rework of swap allocator locks" from Kairui Song redoes
and simplifies the swap allocator locking. A speedup of 400% was
demonstrated for one workload. As was a 35% reduction for kernel
build time with swap-on-zram
- "mm: update mips to use do_mmap(), make mmap_region() internal"
from Lorenzo Stoakes reworks MIPS's use of mmap_region() so that
mmap_region() can be made MM-internal
- "mm/mglru: performance optimizations" from Yu Zhao fixes a few
MGLRU regressions and otherwise improves MGLRU performance
- "Docs/mm/damon: add tuning guide and misc updates" from SeongJae
Park updates DAMON documentation
- "Cleanup for memfd_create()" from Isaac Manjarres does that thing
- "mm: hugetlb+THP folio and migration cleanups" from David
Hildenbrand provides various cleanups in the areas of hugetlb
folios, THP folios and migration
- "Uncached buffered IO" from Jens Axboe implements the new
RWF_DONTCACHE flag which provides synchronous dropbehind for
pagecache reading and writing. To permite userspace to address
issues with massive buildup of useless pagecache when
reading/writing fast devices
- "selftests/mm: virtual_address_range: Reduce memory" from Thomas
Weißschuh fixes and optimizes some of the MM selftests"
* tag 'mm-stable-2025-01-26-14-59' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits)
mm/compaction: fix UBSAN shift-out-of-bounds warning
s390/mm: add missing ctor/dtor on page table upgrade
kasan: sw_tags: use str_on_off() helper in kasan_init_sw_tags()
tools: add VM_WARN_ON_VMG definition
mm/damon/core: use str_high_low() helper in damos_wmark_wait_us()
seqlock: add missing parameter documentation for raw_seqcount_try_begin()
mm/page-writeback: consolidate wb_thresh bumping logic into __wb_calc_thresh
mm/page_alloc: remove the incorrect and misleading comment
zram: remove zcomp_stream_put() from write_incompressible_page()
mm: separate move/undo parts from migrate_pages_batch()
mm/kfence: use str_write_read() helper in get_access_type()
selftests/mm/mkdirty: fix memory leak in test_uffdio_copy()
kasan: hw_tags: Use str_on_off() helper in kasan_init_hw_tags()
selftests/mm: virtual_address_range: avoid reading from VM_IO mappings
selftests/mm: vm_util: split up /proc/self/smaps parsing
selftests/mm: virtual_address_range: unmap chunks after validation
selftests/mm: virtual_address_range: mmap() without PROT_WRITE
selftests/memfd/memfd_test: fix possible NULL pointer dereference
mm: add FGP_DONTCACHE folio creation flag
mm: call filemap_fdatawrite_range_kick() after IOCB_DONTCACHE issue
...
Pull non-MM updates from Andrew Morton:
"Mainly individually changelogged singleton patches. The patch series
in this pull are:
- "lib min_heap: Improve min_heap safety, testing, and documentation"
from Kuan-Wei Chiu provides various tightenings to the min_heap
library code
- "xarray: extract __xa_cmpxchg_raw" from Tamir Duberstein preforms
some cleanup and Rust preparation in the xarray library code
- "Update reference to include/asm-<arch>" from Geert Uytterhoeven
fixes pathnames in some code comments
- "Converge on using secs_to_jiffies()" from Easwar Hariharan uses
the new secs_to_jiffies() in various places where that is
appropriate
- "ocfs2, dlmfs: convert to the new mount API" from Eric Sandeen
switches two filesystems to the new mount API
- "Convert ocfs2 to use folios" from Matthew Wilcox does that
- "Remove get_task_comm() and print task comm directly" from Yafang
Shao removes now-unneeded calls to get_task_comm() in various
places
- "squashfs: reduce memory usage and update docs" from Phillip
Lougher implements some memory savings in squashfs and performs
some maintainability work
- "lib: clarify comparison function requirements" from Kuan-Wei Chiu
tightens the sort code's behaviour and adds some maintenance work
- "nilfs2: protect busy buffer heads from being force-cleared" from
Ryusuke Konishi fixes an issues in nlifs when the fs is presented
with a corrupted image
- "nilfs2: fix kernel-doc comments for function return values" from
Ryusuke Konishi fixes some nilfs kerneldoc
- "nilfs2: fix issues with rename operations" from Ryusuke Konishi
addresses some nilfs BUG_ONs which syzbot was able to trigger
- "minmax.h: Cleanups and minor optimisations" from David Laight does
some maintenance work on the min/max library code
- "Fixes and cleanups to xarray" from Kemeng Shi does maintenance
work on the xarray library code"
* tag 'mm-nonmm-stable-2025-01-24-23-16' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (131 commits)
ocfs2: use str_yes_no() and str_no_yes() helper functions
include/linux/lz4.h: add some missing macros
Xarray: use xa_mark_t in xas_squash_marks() to keep code consistent
Xarray: remove repeat check in xas_squash_marks()
Xarray: distinguish large entries correctly in xas_split_alloc()
Xarray: move forward index correctly in xas_pause()
Xarray: do not return sibling entries from xas_find_marked()
ipc/util.c: complete the kernel-doc function descriptions
gcov: clang: use correct function param names
latencytop: use correct kernel-doc format for func params
minmax.h: remove some #defines that are only expanded once
minmax.h: simplify the variants of clamp()
minmax.h: move all the clamp() definitions after the min/max() ones
minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi test in clamp()
minmax.h: reduce the #define expansion of min(), max() and clamp()
minmax.h: update some comments
minmax.h: add whitespace around operators and after commas
nilfs2: do not update mtime of renamed directory that is not moved
nilfs2: handle errors that nilfs_prepare_chunk() may return
CREDITS: fix spelling mistake
...
Pull modules updates from Petr Pavlu:
- Sign modules with sha512 instead of sha1 by default
- Don't fail module loading when failing to set the
ro_after_init section read-only
- Constify 'struct module_attribute'
- Cleanups and preparation for const struct bin_attribute
- Put known GPL offenders in an array
- Extend the preempt disabled section in
dereference_symbol_descriptor()
* tag 'modules-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux:
module: sign with sha512 instead of sha1 by default
module: Don't fail module loading when setting ro_after_init section RO failed
module: Split module_enable_rodata_ro()
module: sysfs: Use const 'struct bin_attribute'
module: sysfs: Add notes attributes through attribute_group
module: sysfs: Simplify section attribute allocation
module: sysfs: Drop 'struct module_sect_attr'
module: sysfs: Drop member 'module_sect_attr::address'
module: sysfs: Drop member 'module_sect_attrs::nsections'
module: Constify 'struct module_attribute'
module: Handle 'struct module_version_attribute' as const
params: Prepare for 'const struct module_attribute *'
module: Put known GPL offenders in an array
module: Extend the preempt disabled section in dereference_symbol_descriptor().
Pull rv and tools/rtla updates from Steven Rostedt:
- Add a test suite to test the tool
Add a small test suite that can be used to test rtla's basic features
to at least have something to test when applying changes.
- Automate manual steps in monitor creation
While creating a new monitor in RV, besides generating code from
dot2k, there are a few manual steps which can be tedious and error
prone, like adding the tracepoints, makefile lines and kconfig, or
selecting events that start the monitor in the initial state.
Updates were made to try and automate as much as possible among those
steps to make creating a new RV monitor much quicker. It is still
requires to select proper tracepoints, this step is harder to
automate in a general way and, in several cases, would still need
user intervention.
- Have rtla timerlat hist and top set OSNOISE_WORKLOAD flag
Have both rtla-timerlat-hist and rtla-timerlat-top set
OSNOISE_WORKLOAD to the proper value ("on" when running with -k,
"off" when running with -u) every time the option is available
instead of setting it only when running with -u.
This prevents rtla timerlat -k from giving no results when
NO_OSNOISE_WORKLOAD is set, either manually or by an abnormally
exited earlier run of rtla timerlat -u.
- Stop rtla timerlat on signal properly when overloaded
There is an issue where if rtla is run on machines with a high number
of CPUs (100+), timerlat can generate more samples than rtla is able
to process via tracefs_iterate_raw_events. This is especially common
when the interval is set to 100us (rteval and cyclictest default) as
opposed to the rtla default of 1000us, but also happens with the rtla
default.
Currently, this leads to rtla hanging and having to be terminated
with SIGTERM. SIGINT setting stop_tracing is not enough, since more
and more events are coming and tracefs_iterate_raw_events never
exits.
To fix this: Stop the timerlat tracer on SIGINT/SIGALRM to ensure no
more events are generated when rtla is supposed to exit.
Also on receiving SIGINT/SIGALRM twice, abort iteration immediately
with tracefs_iterate_stop, making rtla exit right away instead of
waiting for all events to be processed.
- Account for missed events
Due to tracefs buffer overflow, it can happen that rtla misses
events, making the tracing results inaccurate.
Count both the number of missed events and the total number of
processed events, and display missed events as well as their
percentage. The numbers are displayed for both osnoise and timerlat,
even though for the earlier, missed events are generally not
expected.
For hist, the number is displayed at the end of the run; for top, it
is displayed on each printing of the top table.
- Changes to make osnoise more robust
There was a dependency in the code that the first field of the
osnoise_tool structure was the trace field. If that that ever
changed, then the code work break. Change the code to encapsulate
this dependency where the code that uses the structure does not have
this dependency.
* tag 'trace-tools-v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (22 commits)
rtla: Report missed event count
rtla: Add function to report missed events
rtla: Count all processed events
rtla: Count missed trace events
tools/rtla: Add osnoise_trace_is_off()
rtla/timerlat_top: Set OSNOISE_WORKLOAD for kernel threads
rtla/timerlat_hist: Set OSNOISE_WORKLOAD for kernel threads
rtla/osnoise: Distinguish missing workload option
rtla/timerlat_top: Abort event processing on second signal
rtla/timerlat_hist: Abort event processing on second signal
rtla/timerlat_top: Stop timerlat tracer on signal
rtla/timerlat_hist: Stop timerlat tracer on signal
rtla: Add trace_instance_stop
tools/rtla: Add basic test suite
verification/dot2k: Implement event type detection
verification/dot2k: Auto patch current kernel source
verification/dot2k: Simplify manual steps in monitor creation
rv: Simplify manual steps in monitor creation
verification/dot2k: Add support for name and description options
verification/dot2k: More robust template variables
...
Pull runtime verifier and osnoise fixes from Steven Rostedt:
- Reset idle tasks on reset for runtime verifier
When the runtime verifier is reset, it resets the task's data that is
being monitored. But it only iterates for_each_process() which does
not include the idle tasks. As the idle tasks can be monitored, they
need to be reset as well.
- Fix the enabling and disabling of tracepoints in osnoise
If timerlat is enabled and the WORKLOAD flag is not set, then the
osnoise tracer will enable the migrate task tracepoint to monitor it
for its own workload. The test to enable the tracepoint is done
against user space modifiable parameters. On disabling of the tracer,
those same parameters are used to determine if the tracepoint should
be disabled. The problem is if user space were to modify the
parameters after it enables the tracer then it may not disable the
tracepoint.
Instead, a static variable is used to keep track if the tracepoint
was enabled or not. Then when the tracer shuts down, it will use this
variable to decide to disable the tracepoint or not, instead of
looking at the user space parameters.
* tag 'trace-rv-v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing/osnoise: Fix resetting of tracepoints
rv: Reset per-task monitors also for idle tasks
Pull bitmap updates from Yury Norov:
"This includes const_true() series from Vincent Mailhol, another
__always_inline rework from Nathan Chancellor for RISCV, and a couple
of random fixes from Dr. David Alan Gilbert and I Hsin Cheng"
* tag 'bitmap-for-6.14' of https://github.com:/norov/linux:
cpumask: Rephrase comments for cpumask_any*() APIs
cpu: Remove unused init_cpu_online
riscv: Always inline bitops
linux/bits.h: simplify GENMASK_INPUT_CHECK()
compiler.h: add const_true()
Switch away from using sha1 for module signing by default and use the
more modern sha512 instead, which is what among others Arch, Fedora,
RHEL, and Ubuntu are currently using for their kernels.
Sha1 has not been considered secure against well-funded opponents since
2005[1]; since 2011 the NIST and other organizations furthermore
recommended its replacement[2]. This is why OpenSSL on RHEL9, Fedora
Linux 41+[3], and likely some other current and future distributions
reject the creation of sha1 signatures, which leads to a build error of
allmodconfig configurations:
80A20474797F0000:error:03000098:digital envelope routines:do_sigver_init:invalid digest:crypto/evp/m_sigver.c:342:
make[4]: *** [.../certs/Makefile:53: certs/signing_key.pem] Error 1
make[4]: *** Deleting file 'certs/signing_key.pem'
make[4]: *** Waiting for unfinished jobs....
make[3]: *** [.../scripts/Makefile.build:478: certs] Error 2
make[2]: *** [.../Makefile:1936: .] Error 2
make[1]: *** [.../Makefile:224: __sub-make] Error 2
make[1]: Leaving directory '...'
make: *** [Makefile:224: __sub-make] Error 2
This change makes allmodconfig work again and sets a default that is
more appropriate for current and future users, too.
Link: https://www.schneier.com/blog/archives/2005/02/cryptanalysis_o.html [1]
Link: https://csrc.nist.gov/projects/hash-functions [2]
Link: https://fedoraproject.org/wiki/Changes/OpenSSLDistrustsha1SigVer [3]
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: kdevops <kdevops@lists.linux.dev> [0]
Link: https://github.com/linux-kdevops/linux-modules-kpd/actions/runs/11420092929/job/31775404330 [0]
Link: https://lore.kernel.org/r/52ee32c0c92afc4d3263cea1f8a1cdc809728aff.1729088288.git.linux@leemhuis.info
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Pull kgdb updates from Daniel Thompson:
"A very small set of changes this kernel cycle.
Two cleanups, one switches to kmap_local_page() (from kmap_atomic())
and the other removes a bit of dead code"
* tag 'kgdb-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux:
kdb: Remove unused flags stack
kdb: use kmap_local_page()
Fix the function parameter names to match the function so that
the kernel-doc warnings disappear.
clang.c:273: warning: Function parameter or struct member 'dst' not described in 'gcov_info_add'
clang.c:273: warning: Function parameter or struct member 'src' not described in 'gcov_info_add'
clang.c:273: warning: Excess function parameter 'dest' description in 'gcov_info_add'
clang.c:273: warning: Excess function parameter 'source' description in 'gcov_info_add'
Link: https://lkml.kernel.org/r/20250111062944.910638-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Justin Stitt <justinstitt@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use a ':' instead of a '-' after function parameters to eliminate
kernel-doc warnings.
kernel/latencytop.c:177: warning: Function parameter or struct member 'tsk' not described in '__account_scheduler_latency'
../kernel/latencytop.c:177: warning: Function parameter or struct member 'usecs' not described in '__account_scheduler_latency'
../kernel/latencytop.c:177: warning: Function parameter or struct member 'inter' not described in '__account_scheduler_latency'
Link: https://lkml.kernel.org/r/20250111063019.910730-1-rdunlap@infradead.org
Fixes: ad0b0fd554 ("sched, latencytop: incorporate review feedback from Andrew Morton")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Resending this patch as I haven't received feedback on my initial
submission https://lore.kernel.org/all/20241204182953.10854-1-oxana@cloudflare.com/
For the processes which are terminated abnormally the kernel can provide
a coredump if enabled. When the coredump is performed, the process and
all its threads are put into the D state
(TASK_UNINTERRUPTIBLE | TASK_FREEZABLE).
On the other hand, we have kernel thread khungtaskd which monitors the
processes in the D state. If the task stuck in the D state more than
kernel.hung_task_timeout_secs, the hung_task alert appears in the kernel
log.
The higher memory usage of a process, the longer it takes to create
coredump, the longer tasks are in the D state. We have hung_task alerts
for the processes with memory usage above 10Gb. Although, our
kernel.hung_task_timeout_secs is 10 sec when the default is 120 sec.
Adding additional information to the log that the task is blocked by
coredump will help with monitoring. Another approach might be to
completely filter out alerts for such tasks, but in that case we would
lose transparency about what is putting pressure on some system
resources, e.g. we saw an increase in I/O when coredump occurs due its
writing to disk.
Additionally, it would be helpful to have task_struct->flags in the log
from the function sched_show_task(). Currently it prints
task_struct->thread_info->flags, this seems misleading as the line
starts with "task:xxxx".
[akpm@linux-foundation.org: fix printk control string]
Link: https://lkml.kernel.org/r/20250110160328.64947-1-oxana@cloudflare.com
Signed-off-by: Oxana Kharitonova <oxana@cloudflare.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Ben Segall <bsegall@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
