check_atomic_rmw() open codes the mapping from a BPF_ATOMIC to the register
it reads the old value into, the BPF_STX case of insn_def_regno() open codes
the very same mapping a second time, the const folding and the liveness
transfer functions a third and a fourth time, and BPF JITs need it as well
to know which register a faulting BPF_PROBE_ATOMIC has to clear.
Add a small helper so that all of them can share it. No functional change.
The BPF_LOAD_ACQ case is there for the JITs, which do walk all instruction
classes. const_reg_xfer() loses its explicit BPF_ATOMIC mode test since the
helper checks class and mode itself; the BPF_PROBE_ATOMIC it additionally
accepts cannot be seen there as it is only set from bpf_do_misc_fixups(),
that is, after const folding has run. arg_track_xfer() keeps its mode test
since that also guards the stack clearing next to it.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260811131600.506721-1-daniel@iogearbox.net
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Ning Ding says:
====================
bpf: Compare iterator types during state pruning
Iterator stack slots can be marked MEM_RCU or PTR_UNTRUSTED. The
STACK_ITER check in stacksafe() does not compare this type, so state
pruning can treat these states as equal and prune an unsafe path.
Compare the type and add a test where RCU protection has a gap.
---
Changes in v2:
- Convert the regression test to inline assembly so its verifier-sensitive
control-flow layout is stable.
- Add Eduard Zingerman's Acked-by tag to patch 1.
v1: https://lore.kernel.org/bpf/20260807004320.134069-1-dingning04@gmail.com/
====================
Link: https://patch.msgid.link/20260811035955.132989-1-dingning04@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Kumar Kartikeya Dwivedi says:
====================
Add arena argument support to kfuncs and struct_ops
This is a continuation of patches in [0], with mostly minor changes and
reordering. The motivation is covered in that link. A major change is
moving to two tags (__arena and __arena__nullable) and moving the changes
to JIT to emit more optimized sequences.
Please see commit logs for details.
[0]: https://lore.kernel.org/bpf/20260713024414.3759854-1-tj@kernel.org
Changelog:
----------
v4 -> v5
v4: https://lore.kernel.org/bpf/20260805210427.3218326-1-memxor@gmail.com
* Remove the redundant patch-8 capability comment and duplicate
nullable kfunc test coverage. (Eduard)
* Introduce the final bpf_tramp_arena_base() interface directly with
function-model argument flags, avoiding temporary slot bitmaps and
arena_nullable state; simplify struct_ops pointer validation. (Eduard)
* Simplify kfunc arena nullability classification by using the common
nullable path for both arena suffixes while leaving the function model
to distinguish JIT NULL preservation. (Amery)
* Keep bpf_prog_has_arena_ctx_arg() in bpf_verifier.h from its
introduction so trampoline and verifier users share one inline
definition, avoiding BPF_JIT/BPF_SYSCALL link dependencies.
(Eduard, BPF CI Bot)
* Reject both tracing and extension attachments to struct_ops programs
with arena context arguments, and add fentry, fexit, and freplace
rejection tests. (Eduard, Sashiko)
v3 -> v4
v3: https://lore.kernel.org/bpf/20260803125115.2264733-1-memxor@gmail.com
* Rename __arena_nullable to __arena__nullable and prioritize the
composite suffix over __nullable during argument classification.
(Sashiko, Eduard)
* Resolve instructions before collecting subprograms and kfuncs so kfunc
prototype validation can use associated arena state.
* Move the arena kfunc and JIT-sequence test entry points into
prog_tests/verifier.c. (Eduard)
* Match the generated L0 target and call in nullable JIT assertions.
(Eduard)
* Route arena kfunc validation through the common argument-checking path.
(Amery)
* Reuse btf_func_model argument flags for struct_ops arena arguments
instead of maintaining separate trampoline slot metadata. (Eduard)
* Check the generic-trampoline arena argument invariant at link time and
warn once on violations. (Eduard)
* Reject tracing attachments to struct_ops programs with arena context
arguments whose indirect trampolines convert the pointers. (Sashiko)
v2 -> v3
v2: https://lore.kernel.org/bpf/20260726013105.3689867-1-memxor@gmail.com
* Rebase onto current bpf-next to resolve conflicts.
v1 -> v2
v1: https://lore.kernel.org/bpf/20260715220052.1590783-1-memxor@gmail.com
* Fix documentation to only mention x86 for now. (Sashiko)
* Move arg bitmap from insn_aux_data to kfunc descriptor. (Eduard)
====================
Link: https://patch.msgid.link/20260808003938.3486067-1-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Reject tracing and freplace attachments to a target program with arena
context arguments. The struct_ops indirect trampoline converts those
arguments before entering the target, so a generic tracing trampoline
would otherwise expose arena offsets using the target BTF pointer type.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-14-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Add a test_arena_stack member with eight leading scalar arguments so the
arena pointer is passed on the stack.
The callback validates the first and last scalar ctx slots before
dereferencing the pointer in ctx[8]. This exercises the indirect
trampoline stack layout and arena conversion together, and prevents a
regression where stack arguments are read one slot late.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Tested-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-13-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
save_args() reads stack-passed arguments relative to rbp assuming two
return addresses sit between the saved rbp and the arguments, which
holds when the trampoline is entered through the fentry call from a
traced function. An indirect trampoline is called through a function
pointer, so only the caller's return address is on the stack and the
arguments start at rbp + 16, not rbp + 24. Every stack-passed argument
of a struct_ops callback with more than six argument slots is read one
slot off.
This has gone unnoticed because no in-tree struct_ops member passes
arguments on the stack. The jmp-entry form already accounts for having
a single return address; treat BPF_TRAMP_F_INDIRECT the same way.
Fixes: 473e3150e3 ("bpf, x86: allow function arguments up to 12 for TRACING")
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Tested-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-12-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Add test_arena and test_arena_nullable members to bpf_testmod_ops3 with
arena-tagged stub arguments and kfuncs that forward a caller-provided
pointer to them. The kfuncs take arena-tagged arguments, so each round
trip exercises both conversion directions end to end: the kfunc receives
a kernel arena address and the trampoline converts it back to an arena
pointer for the callback.
The non-nullable callback dereferences its argument with no NULL branch
and captures the raw ctx value, which the trigger program compares
against the arena offset of the passed object, pinning the exact
(u32)(kaddr - kern_vm_start) conversion. The nullable callback verifies
that only a true kernel NULL arrives as NULL. Failure coverage: a
program with no arena is rejected when it loads. The tests run on x86-64
and skip elsewhere, as the programs fail verification where the JIT
lacks arena argument support.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-11-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Pin the exact rebase sequences the JITs emit for __arena and
__arena__nullable kfunc arguments with __jited assertions on x86-64: the
unconditional truncate-and-add, the nullable test-and-skip variant, and
all five argument registers in one call, which also covers the
REX-prefixed encoding of r8 on x86. The capture kfuncs take the argument
without dereferencing, so only the emitted code is under test. The
tests skip without LLVM disassembler support.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-10-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Add arena-argument kfuncs to bpf_testmod, which also exercises the
argument rebasing on module kfuncs, and tests covering the accepted
argument forms (arena pointer, low 32 bits as a scalar, full user
address as a scalar), the exact rebase semantics via capture kfuncs
returning the raw argument (zero low 32 bits arrive as the arena kernel
base under __arena and as NULL under __arena__nullable), five arena
arguments in one call, a mixed __arena plus __arena__nullable call
exercising both bitmasks on one call site, a kernel-side dereference of
an unpopulated page recovering through the scratch page, and the
rejections (no arena in the program, incompatible register type).
The tests run on x86-64 and skip elsewhere, as programs with
arena-tagged kfunc args fail verification where the JIT lacks support.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-9-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Implement the struct_ops arena argument conversion on x86. save_args()
receives the arena base from bpf_tramp_arena_base() and consults the
btf_func_model argument flags as it copies each native argument into the
BPF ctx, routing a marked argument through RAX:
movl %esrc, %eax /* truncate and clear the upper 32 bits */
subl $base_lo, %eax
movq %rax, ctx_slot
A nullable argument tests the full 64-bit kernel pointer first:
movq %rsrc, %rax
testq %rax, %rax
jz 1f
subl $base_lo, %eax
1:
movq %rax, ctx_slot
The 32-bit subtraction is sufficient since (u32)(kaddr - base) ==
(u32)kaddr - (u32)base, and it clears the upper half as the JITs require
of arena pointer registers. Stack-passed arguments already reload
through RAX, so only the subtraction (and the NULL test) is inserted
there.
Keep arena and nullable classification in btf_func_model.
bpf_tramp_arena_base() returns a base only for a single-program
struct_ops indirect trampoline; other trampolines pass zero and perform
no conversion. The size probe reruns the same emission with the same
model and nodes, so the image size matches by construction.
With both the kfunc and struct_ops directions implemented, flip
bpf_jit_supports_arena_args() on for x86.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-8-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Implement arena argument rebasing for kfunc calls on x86. R12 already
holds kern_vm_start whenever the prog has an arena, so each tagged
argument costs two instructions emitted right before the call:
movl %eN, %eN /* truncate, clear the upper 32 bits */
addq %r12, %rN
A nullable argument tests the truncated value and jumps over the add:
movl %eN, %eN
testl %eN, %eN
jz 1f
addq %r12, %rN
1:
addq carries a REX prefix for every argument register and is always
three bytes, so the jz displacement is constant. The sequence is native
code generated after constant blinding has run on the BPF instruction
stream, so blinding never sees the rebase and needs no special handling.
bpf_jit_supports_arena_args() is not flipped yet; that happens when the
struct_ops trampoline side is in place as well.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-7-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
A struct_ops callback cannot receive an arena pointer directly, so
passing one takes two steps. The pointer arrives as a bare u64 that the
callback casts, and because the two sides address the arena through
different bases it also has to be rebased by hand on the way in.
Add the __arena and __arena__nullable stub argument suffixes to make this
convenient. The callback declares the parameter as an arena pointer,
receives it as a PTR_TO_ARENA register, and dereferences it directly,
while the kernel caller just passes the natural kernel arena address
(kaddr). The trampoline converts the value while saving the arguments
into the BPF ctx, ctx[slot] = (u32)(kaddr - kern_vm_start), so the
program never sees a kernel address and nothing rewrites the ctx after
the fact. The converted value keeps the upper 32 bits clear as the JITs
require of arena pointer registers and behaves like any cast_kern'ed
arena pointer, so cast_user recovers the full user-visible address.
__arena converts unconditionally and the kernel caller must not pass
NULL. __arena__nullable preserves NULL, tested on the full 64-bit kernel
pointer, and surfaces to the verifier as PTR_TO_ARENA (but not as a
PTR_TO_ARENA | PTR_MAYBE_NULL). The reason is that PTR_TO_ARENA in the
program's type state already encompasses NULL-ness, so it is not
meaningful to force a NULL check for the program.
The composite suffix intentionally ends in __nullable. Classify
__arena__nullable before the generic suffix so scalar arena pointees do
not take the generic nullable BTF pointer path.
This patch adds the generic side. prepare_arg_info() records arena and
nullable argument flags in the struct_ops function model, and
bpf_tramp_arena_base() returns the arena base for a single-program
struct_ops indirect trampoline. Only that trampoline converts: its
program's arena is fixed at generation time. Generic trampolines can mix
programs with different arenas and reject arena context arguments
defensively, which is unreachable today as only struct_ops programs
carry them. Architectures that do not implement the conversion are
gated out at verification time with bpf_jit_supports_arena_args().
Co-developed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-6-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Passing an arena pointer to a kfunc takes two steps today. There is no
arena pointer argument type, so the pointer crosses the boundary as a
bare scalar, and the kfunc then offsets it by the arena base and casts
it before it can touch the memory. Every such kfunc open-codes the same
translation.
Add the __arena and __arena__nullable argument suffixes to make this more
convenient. The kfunc declares the parameter by its real pointer type
and dereferences it directly, with the JIT rebasing the value at the
call site, rN = kern_vm_start + (u32)rN. No bounds check is needed: the
u32 offset stays within the guard-padded arena kernel mapping, and a
fault on an unpopulated page recovers through the per-arena scratch
page. A suffixed argument accepts a PTR_TO_ARENA or scalar register,
matching global subprog arena arguments.
__arena rebases unconditionally, so the kfunc never sees NULL and a
value with zero in the low 32 bits arrives as the arena base.
__arena__nullable preserves NULL for optional arguments by skipping the
rebase when the truncated value, arena offset 0, is zero. Keeping the
plain form NULL-free saves the NULL test on every call.
The double separator makes the annotations composable:
__arena__nullable also ends in __nullable and naturally follows the
common nullable argument path. Plain __arena follows that path too for
verifier type checking because both forms accept a constant zero; the
function-model flag still determines whether the JIT preserves NULL or
rebases it to the arena base.
This patch adds the verifier side: the suffixes are recognized in
check_kfunc_args() and distilled into argument flags in the function
model stored in the kfunc descriptor. JITs retrieve the model while
emitting the call, avoiding per-call state in insn_aux_data.
JITs declare support with bpf_jit_supports_arena_args() and verification
fails with -ENOTSUPP elsewhere.
Co-developed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-5-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
The kfunc descriptors include argument prototypes generated while calls are
collected. Some argument classifications need program auxiliary state derived
from referenced maps, such as the arena associated with the program.
This avoids a footgun in get_kfunc_arg_type() checks where we do
validation on whether program has prog->aux->arena and it hasn't been
resolved yet.
check_and_resolve_insns() records used maps and populates that state. It must
remain after bpf_check_btf_info(), which applies kernel-side CO-RE relocations,
so that instruction validation and the program tag observe the relocated
instruction stream.
Move only add_kfuncs() after instruction and resource resolution. Subprogram
discovery and validation remain before the full BTF phase because that phase
needs the complete subprogram layout. Add a short comment describing the
resource resolution phase at the call site.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Reviewed-by: Amery Hung <ameryhung@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-4-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
add_subprog_and_kfunc() combines two operations with different ordering
requirements. Subprogram discovery must precede validation of func_info and
line_info, while kfunc descriptors are only needed by the verifier after its
initial program setup is complete.
Split the helper into add_subprogs() and add_kfuncs() so each operation can be
placed according to its actual dependencies. Keep both calls adjacent and in
their existing phase for now, and add short comments describing their roles.
No functional change is intended for valid programs.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Reviewed-by: Amery Hung <ameryhung@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-3-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
BTF processing is split around subprogram discovery. The first phase gets
program BTF and imports func_info because a BTF-tagged exception callback
may not be referenced by any instruction. Subprogram discovery needs this
metadata to find it.
The later phase validates func_info and line_info against the complete
subprogram table and applies CO-RE relocations. This split breaks a real
dependency cycle rather than merely running the same checks early.
Rename bpf_check_btf_info_early() and check_btf_func_early() to preparation
names that reflect this role. Add short call-site comments to make the two
phases and their responsibilities clear.
No functional change is intended.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Reviewed-by: Amery Hung <ameryhung@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-2-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Includes the following test cases:
- a test showing that zero extension flags do not propagate through
state pruning in the unpatched kernel.
- a 32-bit subregister consumed by MOV32 and ALU32 operations
(never zext'ed);
- a 64-bit MOV (never zext'ed);
- a narrow (32-bit) BPF_LDX load whose result is read as 64-bit;
- 32-bit atomic fetch_add and cmpxchg whose result is read as 64-bit;
- a CFG case where a 32-bit definition's upper half is used only on one
of two branches;
- no zext for dead registers;
- LD_ABS defines only lower 32 bits, hence needs zext when the result
is used as 64-bits;
- helper, kfunc and subprogram parameters are considered to use full
64 bits;
- a 32-bit subregister consumed by JMP32 (X/K) operations;
- a 32-bit subregister consumed by JMP (X/K) operations;
- a 64-bit register consumed by both JMP and JMP32 operations
(never zext'ed);
- ALU64 and address space cast operations on arena pointers;
- memory loads using BPF_PROBE_MEM instructions.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260807-static-zext-v4-7-b6c270013c77@gmail.com
After the previous commit bpf_is_reg64() is only used in a context
where destination register's property is queried, and only for
instructions for which insn_def_regno() >= 0. Hence, simplify the
function by:
- removing unused parameters;
- removing code paths considering BPF_JMP{,32} instructions;
- streamlining the condition expressions.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260807-static-zext-v4-6-b6c270013c77@gmail.com
As reported in the thread [1], the verifier's 32-bit operations zero
extension logic is broken. This logic is responsible for correct
semantics of 32-bit operations on s390 architecture.
According to BPF semantics, operation `w1 += 1` is supposed to zero
extend the upper half of the register `r1`. On s390 the JIT relies on
the verifier emitting explicit zero extension before such operations.
The verifier attempts to minimize the amount of zero extensions
inserted by tracking whether upper halves of the 64-bit registers are
ever used. Previously such tracking worked as follows:
- bpf_reg_state->subreg_def field was set by do_check_insn()
for each operation defining lower but not the upper halves
of the register.
- Whenever an operation reading the whole register was verified,
the verifier checked register's subreg_def and set
bpf_insn_aux_data->zext_dst flag as true via a call to
mark_insn_zext() function.
- After the verification was complete, a special pass
bpf_opt_subreg_zext_lo32_rnd_hi32() extended 32-bit operations
with bpf_insn_aux_data->zext_dst set as true by adding
explicit zero extension.
Note that the logic above relies on bpf_reg_state->subreg_def,
which is a property of a current verifier state.
Before the commit [2] two additional steps happened:
- The verifier tracked upper and lower register halves' liveness as
flags REG_LIVE_READ{32,64} in bpf_reg_state->live.
- The function propagate_liveness() called mark_insn_zext()
in order to transfer the knowledge about which registers have
their upper halves alive (and thus might require zero extension).
The commit [2] removed the two steps described above,
hence making possible a situation like below:
- The register's upper half is set and is used on some verification
path P1 and the register happens not to be marked as precise.
- The checkpoint C is created while processing some instruction
between register initialization and usage.
- On some other verification path P2 the register's upper half is not
initialized and that path ends hitting the checkpoint C.
- In such a case the register's initialization on path P2 would lack
zext_dst mark, making it possible for the program to inject
an arbitrary value in the register's upper half.
This commit replaces subreg_def based logic with computing zext_dst
statically, as a part of the bpf_compute_live_registers() analysis:
- The analysis now tracks usage of upper and lower halves of the
registers separately.
- If some instruction defines a 32-bit subregister, but not the whole
register, *and* the upper half of the register is alive after that
instruction, the instruction is marked as zext_dst.
There is one notable drop in precision: whenever a BPF subprogram is
called, all 64 bits of parameter registers are presumed to be used.
The assumption is that such a drop in precision would not inflict
a noticeable performance penalty.
[1] https://lore.kernel.org/bpf/CAGKGUv=sOuqQtA1Ub-5JXfA4FPosJFYKAQE4B79cK+P1erxqtg@mail.gmail.com/
[2] commit 107e169799 ("bpf: disable and remove registers chain based liveness")
Fixes: 107e169799 ("bpf: disable and remove registers chain based liveness")
Reported-by: Min-gyu Kim <gimm78064@gmail.com>
Reported-by: STAR Labs SG <info@starlabs.sg>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/CAGKGUv=sOuqQtA1Ub-5JXfA4FPosJFYKAQE4B79cK+P1erxqtg@mail.gmail.com/
Link: https://lore.kernel.org/bpf/20260807-static-zext-v4-5-b6c270013c77@gmail.com
Extend compute_live_registers() to track upper and lower register
halves' liveness separately. This is mostly straightforward:
- use/def masks are extended to track 2 bits per register;
- compute_insn_live_regs() is updated to properly track these
2 bits according to the instruction semantics.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260807-static-zext-v4-4-b6c270013c77@gmail.com
bpf_do_misc_fixups() converts the following address space cast
instructions to 32-bit moves:
- cast from address space 1 (user) to address space 0 (kernel)
- cast from address space 0 (kernel) to address space 1 (user)
iff associated arena map has a BPF_F_NO_USER_CONV flag.
Extract a predicate detecting such instructions for use in the
following patches.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260807-static-zext-v4-2-b6c270013c77@gmail.com
At the moment there are more callsites that want bpf_verbose_insn() to
not print a newline after the instruction, than callsites that want a
newline. Drop '\n' from disasm.c. Non-functional change.
The changes in bpftool are verified by writing a bpf program using a
variety of instructions and comparing `prog dump xlated` output in the
following modes: plain, opcodes, visual, visual opcodes. The output
before and after the changes is identical.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Quentin Monnet <qmo@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260807-static-zext-v4-1-b6c270013c77@gmail.com
Pull BPF fixes from Daniel Borkmann:
- Fix BPF verifier to preserve full pointer state for commuted
scalar += pointer arithmetic (Yiyang Chen, Eduard Zingerman)
- Fix a use-after-free of request sockets in the BPF TCP iterator
batching (Jose Fernandez)
- Fix a use-after-free of sk_redir in the BPF sockmap send verdict
path (Chengfeng Ye)
- Fix a netns reference imbalance in the BPF conntrack kfuncs
(Chengfeng Ye)
- Fix bpf_get_fsverity_digest() dynptr assumptions and silent
digest truncation (Eric Biggers)
- Fix bpf_tcp_{gen,check}_syncookie to check sk_state before
sk_protocol to make sure it is a full socket (Luxiao Xu)
- Fix rqspinlock to reset the tail when preserving the queue
on deadlock (Kumar Kartikeya Dwivedi)
* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
rqspinlock: Reset tail when preserving queue on deadlock
bpf: Check sk_state before sk_protocol in bpf_tcp_*_syncookie
fsverity: Fix silent truncation in bpf_get_fsverity_digest()
fsverity: Fix bpf_get_fsverity_digest() dynptr assumptions
bpf: tcp: Fix use-after-free in bpf_iter_tcp_established_batch()
bpf: Fix netns reference imbalance in conntrack kfuncs
bpf, sockmap: Fix sk_redir use-after-free in send verdict
selftests/bpf: Cover commuted pointer state propagation
bpf: Propagate untrusted pointer state in commuted arithmetic
bpf: Preserve pointer state for commuted arithmetic
bpf: Simplify sanitize_err() signature
Pull vkm fixes from Paolo Bonzini:
"s390:
- fix a lot of small bugs and races
x86:
- fix missing locking related to KVM_CAP_MOVE_ENC_CONTEXT_FROM
- warn on creating a new page table that is the child of an invalid
one, and limit damage before it's too late
- disable use of INVLPGA when NPT is enabled, because it doesn't seem
to flush TLBs correctly"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (26 commits)
KVM: x86/mmu: WARN and clear role.invalid when creating a child shadow page
KVM: SVM: Serialize accesses to the owner and mirror list with separate lock
KVM: SVM: make svm_flush_tlb_gva do a full asid flush if NPT enabled
KVM: s390: Fix cleanup in kvm_s390_pv_create_cpu()
KVM: s390: Fix ordering when adding to SCA
KVM: s390: Return -EINTR if a signal is pending while faulting-in
KVM: s390: Free the mmu cache when kvm_arch_vcpu_create() fails
KVM: s390: ucontrol: Add missing locking around gmap_remove_child()
KVM: s390: cmma: Fix dirty tracking when removing memslot
KVM: s390: Fix race in __do_essa()
KVM: s390: Fix leaking of PGM_ADDRESSING to userspace
KVM: s390: ucontrol: Fix sca_clear_ext_call()
KVM: s390: Fix overclearing ESCA in case of error
KVM: s390: Fix kvm_s390_vcpu_unsetup_cmma()
KVM: s390: Do not free SCA if it was not allocated
KVM: s390: Fix unlikely NULL gmap dereference
s390/vfio_ccw: Implement a crw lock
s390/vfio_ccw: Selectively expand io_mutex
s390/vfio_ccw: Move cp cleanup out of not operational
s390/vfio_ccw: Cancel existing workqueues
...
Pull thermal control fixes from Rafael Wysocki:
"Revert three thermal core updates, two recent ones and one older.
The recent ones attempted to fix a design issue in the thermal core
and simplify code on top of that, but they made changes visible to
user space and made it unhappy.
The older one is a misguided code cleanup that introduced a
(potentially nasty) bug"
* tag 'thermal-7.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
Revert "thermal/drivers/hwmon: Cleanup coding style a bit"
Revert "thermal: hwmon: Register a hwmon device for each thermal zone"
Revert "thermal: hwmon: Use extra_groups for adding temperature attributes"
Pull sound fixes from Takashi Iwai:
"A collection of small fixes since the last pull request. More than
few, but an enough-manageable amount at this time.
USB-audio:
- UAF, OOB and such hardening fixes for USB-audio, usx2y and
us144mkii
- Mixer regression fixes for Logitech PRO X 2 LIGHTSPEED headset and
M-Audio Fast Track Ultra
HD-audio:
- Fix for an ACPI reference leak in TAS2781 HDA side-codec
ASoC:
- Fixes the default tables for Cirrus Logic codecs
- Fixes for invalid enum accesses for Qualcomm LPASS
- Error handling and robustness fixes for Intel SOF & Soundwire
- DMI quirks for a few AMD devices"
* tag 'sound-7.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (22 commits)
ALSA: usb-audio: Fix sticky mixer regressions on M-Audio Fast Track Ultra
ASoC: cs4265: sort the register default table
ASoC: cs35l45: sort the register default table
ASoC: cs35l41: sort the register default table
ASoC: amd: yc: Add DMI quirk for MSI Raider A18 HX A7VHG
ASoC: amd: yc: Add DMI quirk for Xiaomi RedmiBook 16 2025
ALSA: usx2y: bound the hwdep mmap fault offset
ALSA: usb-audio: fix OOB write on Type II inbound URBs
ALSA: us144mkii: re-anchor capture URBs on resubmission
ALSA: FCP: fix OOB write in fcp_meter_ctl_get()
MAINTAINERS: add SpacemiT K1/K3 I2S entry
ASoC: rt5645: Make the Kconfig symbol user selectable
ALSA: usb-audio: Add QUIRK_FLAG_MIXER_GET_CUR_BROKEN for Logitech PRO X 2 LIGHTSPEED
ALSA: hda/tas2781: fix ACPI reference handling
ASoC: codecs: lpass-wsa-macro: Fix enum kcontrol accesses
ASoC: codecs: lpass-tx-macro: Fix enum kcontrol accesses
ASoC: SOF: ipc4-pcm: Continue the pipeline trigger in case of IPC timeout
ASoC: amd: yc: Add DMI quirk for HP Victus Laptop 16-e1xxx
ASoC/soundwire: Intel: reset the PCMSyCM registers in hda_sdw_bpt_close
ASoC: SOF: sof-audio: Fix error path in sof_widget_setup_unlocked()
...
Add a verifier test that a BPF_LOAD_ACQ from a rdonly_untrusted_mem pointer
(PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED, obtained via bpf_rdonly_cast())
is rejected. Such a source requires BPF_PROBE_MEM fault protection which
is not applied to atomic loads; without the verifier fix the load is accepted
and would crash the kernel on a fault.
# LDLIBS=-static PKG_CONFIG='pkg-config --static' ./vmtest.sh -- ./test_progs -t verifier_load_acquire
[...]
#621/1 verifier_load_acquire/load-acquire, 8-bit:OK
#621/2 verifier_load_acquire/load-acquire, 8-bit @unpriv:OK
#621/3 verifier_load_acquire/load-acquire, 16-bit:OK
#621/4 verifier_load_acquire/load-acquire, 16-bit @unpriv:OK
#621/5 verifier_load_acquire/load-acquire, 32-bit:OK
#621/6 verifier_load_acquire/load-acquire, 32-bit @unpriv:OK
#621/7 verifier_load_acquire/load-acquire, 64-bit:OK
#621/8 verifier_load_acquire/load-acquire, 64-bit @unpriv:OK
[...]
#621/19 verifier_load_acquire/load-acquire from rdonly_untrusted_mem pointer:OK
#621/20 verifier_load_acquire/load-acquire with invalid register R15:OK
#621/21 verifier_load_acquire/load-acquire with invalid register R15 @unpriv:OK
#621/22 verifier_load_acquire/load-acquire from pkt pointer:OK
#621/23 verifier_load_acquire/load-acquire from flow_keys pointer:OK
#621/24 verifier_load_acquire/load-acquire from sock pointer:OK
#621 verifier_load_acquire:OK
Summary: 1/24 PASSED, 0 SKIPPED, 0 FAILED
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260806201047.333389-6-daniel@iogearbox.net
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Add stream_arena_load_acquire_fault, which performs a load-acquire from an
unmapped arena address, next to the existing read and write fault tests.
The test covers both halves of the JIT bug that treated a load-acquire as
a store when populating its exception table entry:
- the fault has to be reported as a READ, and at the address held by
the source register, which __stderr() and test_address() check, and
- the destination register has to be cleared by the fault handler,
which the program checks by poisoning it before the load-acquire
and returning it, so __retval(0) fails if it is left untouched
Note, load-acquire is open coded since linux/filter.h cannot be included
alongside vmlinux.h.
# LDLIBS=-static PKG_CONFIG='pkg-config --static' ./vmtest.sh -- ./test_progs -t stream_arena_fault_address
[...]
#462/1 stream_arena_fault_address/read_fault:OK
#462/2 stream_arena_fault_address/write_fault:OK
#462/3 stream_arena_fault_address/load_acquire_fault:OK
#462 stream_arena_fault_address:OK
Summary: 1/3 PASSED, 0 SKIPPED, 0 FAILED
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260806201047.333389-5-daniel@iogearbox.net
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Same problem as on x86-64: add_exception_handler() decides whether an
instruction is a load by its class, and a load-acquire is of BPF_STX
class even though it reads from src_reg into dst_reg. As a result ...
if (BPF_CLASS(insn->code) != BPF_LDX)
dst_reg = DONT_CLEAR;
... drops the register to clear, and ...
if (BPF_CLASS(insn->code) == BPF_LDX)
arena_reg = bpf2a64[insn->src_reg];
else
arena_reg = bpf2a64[insn->dst_reg];
... hands ex_handler_bpf() the value register instead of the address
register. A load-acquire from an arena pointer that faults on an
unmapped page is therefore reported as a WRITE at a bogus address,
and dst_reg keeps its previous value instead of being cleared to 0.
Note that emit_atomic_ld_st() already picks src_reg as the address
for BPF_LOAD_ACQ, so only the exception table metadata was out of sync
with the emitted access.
Same as on x86-64, use bpf_atomic_is_load_acq() so a load-acquire takes
the load path.
Fixes: 9bb12368d5 ("bpf, arm64: Support load-acquire and store-release instructions")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/bpf/20260806201047.333389-4-daniel@iogearbox.net
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
A load-acquire from an arena pointer is converted to BPF_PROBE_ATOMIC and
gets an exception table entry, but the entry is filled in as if it were a
store, since populate_extable() decides based on instruction class alone
and a load-acquire is of BPF_STX class:
if (BPF_CLASS(insn->code) == BPF_LDX) {
arena_reg = reg2pt_regs[src_reg];
fixup_reg = reg2pt_regs[dst_reg];
} else {
arena_reg = reg2pt_regs[dst_reg];
fixup_reg = DONT_CLEAR;
}
For a load-acquire dst_reg holds the loaded value and src_reg holds the
address, so both assignments in the else branch are wrong. On a fault
over an unmapped arena page ex_handler_bpf() then:
- computes the reported address from the value register instead
of the address register
- reports the access as a WRITE, since it derives the direction
from fixup_reg == DONT_CLEAR
- leaves dst_reg untouched, so the program continues with a stale
value instead of the 0 that BPF_PROBE_* loads deliver
The access itself is emitted correctly, emit_atomic_ld_st_index() uses
src_reg as the address, so this is a broken probe contract and a wrong
diagnostic rather than a memory safety issue.
Use bpf_atomic_is_load_acq() helper so a load-acquire takes the load path.
Fixes: 5341c9a4d8 ("bpf, x86: Support load-acquire and store-release instructions")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260806201047.333389-3-daniel@iogearbox.net
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
A load-acquire is the only BPF_STX class instruction that reads from
src_reg into dst_reg, that is, it has the operand roles of a BPF_LDX.
JIT code which tells loads from stores apart by instruction class alone
has to special case it, for example when deciding which register holds
the faulting address and which one to clear from an exception handler.
riscv64 already does so, open coded as a bare insn->imm test. Add a
bpf_atomic_is_load_acq() helper and convert riscv64 over to it, so that
the x86-64 and arm64 JITs can use the same helper in subsequent patches.
Unlike bpf_atomic_is_load_store(), which presumes that its argument is
already known to be a BPF_ATOMIC instruction, the new helper is called
from code which still sees all instruction classes, so it checks class
and mode itself.
Also, move bpf_atomic_is_load_store() to filter.h next to BPF_ATOMIC_OP,
so that both helpers stay together. No functional change intended.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260806201047.333389-2-daniel@iogearbox.net
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
A BPF_LOAD_ACQ is not rewritten to a BPF_PROBE_MEM load by the verifier,
unlike a regular BPF_LDX, so the JIT emits a plain load with no exception
table entry and a fault panics the kernel instead of being handled.
Reject the source pointer types that a BPF_LDX would have had that fault
protection applied to, i.e. the ones bpf_convert_ctx_accesses() turns
into BPF_PROBE_MEM: a bare PTR_TO_BTF_ID, PTR_TO_BTF_ID | PTR_UNTRUSTED,
PTR_TO_BTF_ID | MEM_ALLOC | PTR_UNTRUSTED and PTR_TO_MEM | MEM_RDONLY |
PTR_UNTRUSTED.
This is reachable e.g. by loading ->mm out of a trusted task_struct
yields an untrusted pointer to mm_struct, and it is NULL for a kernel
thread:
[...]
SEC("tp_btf/sched_switch")
int BPF_PROG(demo, bool preempt, struct task_struct *prev,
struct task_struct *next)
{
struct mm_struct *mm = next->mm; /* untrusted */
out_ldx = (__u64)mm->pgd; /* BPF_LDX */
out_acq = load_acquire(&mm->pgd); /* BPF_LOAD_ACQ */
return 0;
}
[...]
Both dereference the same pointer, but only the BPF_LDX is protected
(x86-64 JIT, jump targets shown prog-relative):
[...]
; out_ldx = (__u64)mm->pgd;
17: movq $-10485760, %r10
1e: movq %rsi, %r11
21: addq $184, %r11
28: subq %r10, %r11
2b: movabsq $140737498841088, %r10
35: cmpq %r10, %r11
38: ja 0x3e <-- kernel addr?
3a: xorl %edi, %edi <-- no: dst = 0, skip the load
3c: jmp 0x45
3e: movq 184(%rsi), %rdi <-- yes: load + extable entry
[...]
; load_acquire(&mm->pgd)
53: movq %rsi, %rdi
56: movq 184(%rdi), %rax <-- no check, no extable entry
[...]
Note that BPF_PROBE_MEM is not visible in a bpftool xlated dump, as
bpf_insn_prepare_dump() rewrites it back to BPF_MEM.
A PTR_TRUSTED pointer is deliberately not on the list. Such a load is
not converted either, but it does not need to be, since the pointer is
guaranteed live, so load-acquire from it stays allowed.
The check is gated on BPF_LOAD_ACQ so that atomic RMW and store-release
error messages are unchanged; writes (RMW / store-release) to such
pointers are already rejected elsewhere, so only load-acquire needs this.
Fixes: 880442305a ("bpf: Introduce load-acquire and store-release instructions")
Reported-by: STAR Labs SG <info@starlabs.sg>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260806201047.333389-1-daniel@iogearbox.net
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
The recent fix for sticky mixer volumes caused regressions of M-audio
Fast Track Ultra device, where the mixer state is kept to the default
value.
Add the quirk entries to tolerate the broken mixer behavior. As the
device is known to work in the implicit feedback mode, explicitly
enable the implicit feedback mode, too.
Since there are two FTU models that are almost identical, both entries
are added in this patch (0763:2080 and 0763:2081).
Fixes: 86aa1ea1f1 ("ALSA: usb-audio: Do not expose sticky mixers")
Link: https://bugzilla.suse.com/show_bug.cgi?id=1273166
Link: https://patch.msgid.link/20260807083418.1712585-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Explicitly clear role.invalid when deriving a child shadow page's role from
its parent to harden against bugs elsewhere in KVM, as violating KVM's
invariant that invalid pages are NOT on the list of active MMU pages leads
to use-after-free due to __kvm_mmu_prepare_zap_page() using list_add()
instead of list_move() when processing an invalid shadow page, i.e. makes a
bad situation far worse.
Yell loudly if the parent is invalid, as it means KVM has missed a validity
check, i.e. KVM is attempting to map memory using an invalid/obsolete root,
but continue on as the child is otherwise still a valid shadow page.
==================================================================
BUG: KASAN: slab-use-after-free in __kvm_mmu_get_shadow_page+0x1817/0x1860 [kvm]
Write of size 8 at addr ff11000153dd1368 by task repro/853
CPU: 1 UID: 1000 PID: 853 Comm: repro Not tainted 7.2.0-rc2-3aec122bdcaf-next-vm #5 PREEMPT
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
Call Trace:
<TASK>
dump_stack_lvl+0x4b/0x70
print_report+0x153/0x49c
kasan_report+0xbc/0xf0
__kvm_mmu_get_shadow_page+0x1817/0x1860 [kvm]
mmu_alloc_root+0x141/0x320 [kvm]
kvm_mmu_load+0x612/0x20f0 [kvm]
kvm_arch_vcpu_ioctl_run+0x3dd5/0x6150 [kvm]
kvm_vcpu_ioctl+0x5e4/0x10d0 [kvm]
__x64_sys_ioctl+0x131/0x1b0
do_syscall_64+0x67/0x5f0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
</TASK>
Allocated by task 853:
kasan_save_stack+0x20/0x40
kasan_save_track+0x14/0x30
__kasan_slab_alloc+0x5f/0x70
kmem_cache_alloc_noprof+0xfe/0x2e0
__kvm_mmu_topup_memory_cache+0x135/0x530 [kvm]
paging64_page_fault+0x318/0x1e30 [kvm]
kvm_mmu_do_page_fault+0x21d/0x630 [kvm]
kvm_mmu_page_fault+0x18c/0x17b0 [kvm]
kvm_arch_vcpu_ioctl_run+0x1f35/0x6150 [kvm]
kvm_vcpu_ioctl+0x5e4/0x10d0 [kvm]
__x64_sys_ioctl+0x131/0x1b0
do_syscall_64+0x67/0x5f0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
Freed by task 853:
kasan_save_stack+0x20/0x40
kasan_save_track+0x14/0x30
kasan_save_free_info+0x3b/0x60
__kasan_slab_free+0x43/0x70
kmem_cache_free+0xe2/0x400
kvm_mmu_commit_zap_page.part.0+0x1e2/0x310 [kvm]
kvm_mmu_free_roots+0x283/0x560 [kvm]
kvm_arch_vcpu_ioctl_run+0x33c8/0x6150 [kvm]
kvm_vcpu_ioctl+0x5e4/0x10d0 [kvm]
__x64_sys_ioctl+0x131/0x1b0
do_syscall_64+0x67/0x5f0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
Reported-by: Hyunwoo Kim <imv4bel@gmail.com>
Fixes: a770f6f28b ("KVM: MMU: Inherit a shadow page's guest level count from vcpu setup")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Ihor Solodrai says:
====================
resolve_btfids: Implement BTF tags emission for kfuncs
BTF data for the kernel is generated through the following pipeline:
* DWARF is emitted by the compiler
* pahole reads in DWARF and produces BTF
* resolve_btfids makes kernel-specific btf2btf transformation and
patches .BTF_ids section
This is orchestrated by link-vmlinux.sh, gen-btf.sh and Makefile.btf
in ./scripts directory.
Historically kernel-specific BTF features were implemented in pahole,
and controlled by the feature flags. This requires kernel build
process to be aware of pahole version used for the build to set
correct runtime arguments for BTF encoding [1].
This is a burden which can be alleviated by splitting kernel/module
BTF generation in two stages:
1. Generic BTF generation from the kernel source code.
2. Kernel-specific BTF modifications to support various BPF features.
So far both stages were fused in pahole's BTF encoding. By moving
stage (2) in-tree, the dependency of kernel build on pahole can become
much more loose.
resolve_btfids is already responsible for a few kernel-specific BTF
modifications:
* .BTF.base generation for modules [2]
* BTF sorting [3]
* KF_IMPLICIT_ARGS support [4]
This series completes the migration by emitting BTF kfunc annotations
in-tree: the "bpf_kfunc" and "bpf_fastcall" decl tags and the arena
"address_space(1)" type attribute, dropping the corresponding pahole
feature flags.
The three annotations depend on two pahole feature flags:
"decl_tag_kfuncs" and "attributes". Since emission is unconditional,
each flag has to be dropped in the same commit as the emission that
replaces it.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/Makefile.btf?h=v7.1-rc5
[2] https://docs.kernel.org/bpf/btf.html#btf-base-section
[3] https://lore.kernel.org/bpf/20260109130003.3313716-4-dolinux.peng@gmail.com/
[4] https://lore.kernel.org/bpf/20260120222638.3976562-1-ihor.solodrai@linux.dev/
[5] https://lore.kernel.org/bpf/20260722233518.778854-1-ihor.solodrai@linux.dev/
[6] https://lore.kernel.org/bpf/20260617210619.1562858-1-ihor.solodrai@linux.dev/
---
v2->v3:
* Refactoring in patch #2 (Eduard)
* restructure add_arena_tagged_proto() such that first we copy the
func proto and then update param types in place
* push error messages down to arena_tag_ptr()
* introduce is_arena_arg() helper
* Docs cleanup in patch #6 (Eduard)
* Add stats in commit message for patch #1
v2: https://lore.kernel.org/bpf/20260805230648.2354989-1-ihor.solodrai@linux.dev/
v1->v2:
* The bottom part of v1 has already been landed [5][6].
* New patch #1: run btf__dedup() in finalize_btf().
* Drop the "ensure" pattern. Emission is unconditional; kbuild owns
the pahole flags, so assume input BTF is not already tagged.
* Each pahole flag is now dropped in the same commit as the emission
that replaces it.
* Fail hard with an error on invalid kfunc declarations such as an
arena flag naming a missing argument or a non-pointer type.
* Various cleanups and nits (Andrii, Emil, Jiri, Sashiko).
v1: https://lore.kernel.org/bpf/20260601221805.821394-1-ihor.solodrai@linux.dev/
---
====================
Link: https://patch.msgid.link/20260807032029.78092-1-ihor.solodrai@linux.dev
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
For kfuncs flagged with KF_ARENA_RET, KF_ARENA_ARG1 or KF_ARENA_ARG2,
the address_space(1) attribute (a type tag with kflag=1) must be
emitted for the corresponding type in BTF. This was previously done by
pahole via the "attributes" BTF feature [1].
Implement the emission of the arena attributes in resolve_btfids: for
flagged kfuncs create a new function prototype with updated BTF types.
The original proto may be shared with sibling FUNCs, so it is not
modified in place.
Emission is unconditional: kbuild controls the pahole flags, so the
input BTF is expected to not have these attributes. Invalid
declarations are reported as errors.
Drop the "attributes" pahole feature from scripts/Makefile.btf
resolve_btfids now emits them for all supported pahole versions.
[1] https://lore.kernel.org/dwarves/20250228194654.1022535-1-ihor.solodrai@linux.dev/
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://patch.msgid.link/20260807032029.78092-3-ihor.solodrai@linux.dev
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
btf2btf() adds new types to the BTF: the KF_IMPLICIT_ARGS transform
synthesizes an _impl FUNC together with its FUNC_PROTO and copies of the
kfunc's decl tags. Nothing deduplicates them afterwards. pahole runs
btf__dedup() on its own output, but that happens before resolve_btfids
sees the BTF, so any type the tool itself creates is emitted as-is, even
when a structurally identical type is already present.
Call btf__dedup() at the start of finalize_btf(), so that base
distillation and the by-name sort both operate on the canonical set of
types.
On an x86_64 build with the BPF selftests config this removes 17
duplicate FUNC_PROTOs from vmlinux BTF.
The dedup call increases runtime of resolve_btfids on vmlinux by 30-40%.
The performance hit is an acceptable cost to keep kernel BTF deduped [1].
[1] https://lore.kernel.org/bpf/986e6f4e-4b51-4440-a37c-9624906d7370@linux.dev/
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://patch.msgid.link/20260807032029.78092-2-ihor.solodrai@linux.dev
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Pull MM fixes from Andrew Morton:
"17 hotfixes. 15 are cc:stable. 16 are for MM.
There's a patch series from Lorenzo "mm: fix UAF caused by race
between ptdump and vmap pgtable freeing" which addresses a quite old
bug in the ptdump code.
And another series also from Lorenzo which fixes a four year old bug
in the huge_zero_folio handling.
A series from SJ fixes a few possible divide-by-zero issues which
Sashiko sniffed out. And a series which fixes handling of the
commit_inputs parameters.
The remainder are singletons, please see their changelogs for details"
* tag 'mm-hotfixes-stable-2026-08-06-18-44' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
mm/damon: adjust isolated pages stat for DAMOS_MIGRATE_{HOT,COLD}
mm/damon/ops-common: putback folios on invalid migrate nid
mm/huge_memory: initialise workingset state before folio split
mm/page_table_check: skip special zero mappings
mm/damon/lru_sort: skip damon_call() if ctx has not started
mm/damon/reclaim: skip damon_call() if ctx has not started
mm/damon/lru_sort: error out for >10000 active_mem_bp
samples/damon/mtier: error out for zero quota goal target values
mailmap: map old addresses to Danila Tikhonov
mm/huge_memory: separate out CONFIG_PERSISTENT_HUGE_ZERO_FOLIO logic
mm/huge_memory: fix huge_zero_pfn race
MAINTAINERS: update address for Brendan Jackman
mm/filemap: __filemap_add_folio() restore index before retrying
microblaze: restore the page alignment of swapper_pg_dir
arm64: remove redundant concurrent ptdump UAF mitigation
mm/ptdump: always stabilise against page table freeing using init_mm
mm/vmalloc: acquire init_mm lock on huge vmap to avoid ptdump UAF
Pull smb server fixes from Steve French:
- Reject Pattern_V1 payloads when Pattern_V1 support was not
negotiated
- Validate compression transform flags and chained mode before
allocating the decompression buffer
- Enforce the pre-authentication PDU size limit before allocating
the decompression buffer, preventing compressed requests from
bypassing the limit
* tag 'v7.2-rc6-smb3-server-fixes' of git://git.samba.org/ksmbd:
ksmbd: apply the pre-authentication PDU limit when decompressing
ksmbd: validate compression Flags before kvmalloc
smb: compress: reject Pattern_V1 when not negotiated
