Pull bpf fixes from Alexei Starovoitov:
 "This mainly contains verifier fixes that address bugs reported by
  Nicholas Carlini.

   - Fix incorrect non-NULL inference in pointer comparisons: pointer
     types that may be NULL at runtime, pointers with unbounded offsets,
     JMP32 comparisons with zero, and imprecise zero registers (Eduard
     Zingerman)

   - Fix precision tracking for half-dead zero spills, ld_abs/ld_ind
     implicit subprog exit, bpf_loop() callbacks, linked scalar ids and
     NULL call arguments (Eduard Zingerman)

   - Reject BPF_PSEUDO_FUNC reference to the main program, fix zero
     extension of arena 32-bit cmpxchg, don't rewrite bpf_fastcall
     patterns entered by a jump (Eduard Zingerman)

   - Fix percpu map update and BPF_F_CPU validation with sparse CPU IDs
     (Hui Su)

   - Fix NULL-ptr-derefs in bpf_snprintf_btf() for void and VAR types,
     and reject key-less BTF for hash maps (Jiayuan Chen)

   - Various fixes (Kumar Kartikeya Dwivedi):
       - Fix out-of-bounds access in disassembler on invalid LDSX
         instruction
       - mark siginfo of signal tracepoints as scalar and
         sched_process_wait argument as nullable
       - mark faultable stack helpers as sleepable
       - reject tail calls and legacy packet loads from callbacks
       - enforce rbtree callback lock restrictions for resilient locks
       - require MEM_PERCPU for percpu kptr stores
       - clear NON_OWN_REF after RCU protection ends
       - mark NULL kptr stores precise
       - preserve inner map identity in callback frames
       - reject non-scalar bpf_loop() iteration counts

   - Fix trampoline allocation slowdown on x86 by using
     EXECMEM_MODULE_DATA (Mike Rapoport)

   - Keep bpf_refcount_acquire() nullable for borrowed RCU kptrs and
     reject untrusted allocated-object pointers (Ning Ding)

   - Fix special fields handling in recycled rhtab elements (Nuoqi Gui,
     Yuan Chen)"

* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: (86 commits)
  bpf, riscv: Make arena support depend on ZACAS
  selftests/bpf: Test pointer bpf_loop iteration count rejection
  bpf: Reject non-scalar bpf_loop iteration counts
  bpf: use mark_arg_precision() in check_mem_size_reg()
  bpf: propagate mark_chain_precision() errors out of loop_flag_is_zero()
  selftests/bpf: precision of a NULL global subprogram BTF_ID argument
  bpf: mark a NULL BTF_ID argument of a global subprogram precise
  selftests/bpf: precision of a NULL kfunc argument
  bpf: mark a NULL kfunc argument precise
  selftests/bpf: precision of a NULL global subprogram memory argument
  bpf: mark a NULL memory argument of a call precise
  selftests/bpf: precision of a NULL helper argument
  bpf: mark a NULL call argument precise
  selftests/bpf: Test inner map identities in callbacks
  bpf: Preserve inner map identity in callback frames
  selftests/bpf: Test imprecise scalar kptr stores
  bpf: Mark NULL kptr stores precise
  selftests/bpf: Test rhtab kptr cancellation semantics
  bpf: Cancel special fields when recycling rhtab elements
  selftests/bpf: Test timer field on recycled rhtab element
  ...

bpf_loop() declares its nr_loops argument as ARG_ANYTHING. Privileged
programs may pass pointer values to such arguments, so check_func_arg()
lets a pointer-valued R1 reach the helper-specific checks.

Since commit bb124da69c47 ("bpf: keep track of max number of bpf_loop
callback iterations"), the verifier marks R1 precise and reads its upper
bound to limit callback simulation. Precision backtracking only accepts
scalar registers, so passing a pointer instead triggers the "backtracking
misuse" verifier warning. Kernels with panic_on_warn enabled subsequently
panic.

Introduce ARG_SCALAR for helper arguments that only accept scalar values
and use it for bpf_loop() nr_loops. Generic helper argument validation then
rejects pointers before loop inlining and precision processing.

Fixes: bb124da69c47 ("bpf: keep track of max number of bpf_loop callback iterations")
Reported-by: syzbot+7b47f87674e9a1569110@syzkaller.appspotmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://patch.msgid.link/20260905014735.1452988-2-memxor@gmail.com
Closes: https://lore.kernel.org/bpf/6a9ad24c.b5d4176b.238c3e.0001.GAE@google.com/
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>

This is another run of the Coccinelle script for converting kmalloc()
family of allocations to kmalloc_obj() via the existing rules in
scripts/coccinelle/api/kmalloc_objs.cocci

This catches both the set of kmalloc() uses added since the first
kmalloc_obj() conversions in v7.0 and adds a large group missed in the
first pass due to Coccinelle not interacting well with the cleanup.h
scoped_...() family of macros[1]. I worked around this with spatch's
"--macro-file" argument to a file with all the scoped_...() macros mapped
to Coccinelle's YACFE_ITERATOR[2] as that was the closest viable control
flow indicator I could find.

Build tested allmodconfig on x86, arm64, arm, loongarch, mips, powerpc,
riscv, and s390 with no new warnings.

Link: https://lore.kernel.org/lkml/202609021314.8A9C0B8@keescook/ [1]
Link: https://github.com/coccinelle/coccinelle/blob/master/standard.h [2]
Signed-off-by: Kees Cook <kees+treewide@kernel.org>

Use newly added mark_arg_precision() helper in check_mem_size_reg().

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-10-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Stop verification if mark_chain_precision() fails when called from
loop_flag_is_zero(). No functional change intended for the paths where
backtracking succeeds.

Fixes: 1ade23711971 ("bpf: Inline calls to bpf_loop when callback is known")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-9-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

btf_check_func_arg_match() accepts a NULL register for an
ARG_PTR_TO_BTF_ID argument tagged __arg_nullable and skips
check_reg_type() and check_func_arg_reg_off() without marking the
register precise. Hence a checkpoint created on such a path would
prune against arbitrary scalar value.

Fixes: e2b3c4ff5d18 ("bpf: add __arg_trusted global func arg tag")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-7-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

check_mem_reg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

The argument may live on the stack rather than in a register when a
call has more than MAX_BPF_FUNC_REG_ARGS arguments, hence the new
mark_arg_precision() helper.

Fixes: e5069b9c23b3 ("bpf: Support pointers in global func args")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-3-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

check_func_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

check_helper_call() enforces second parameter of the
bpf_get_local_storage() to be zero, w/o marking the underlying scalar
register precise. Hence a checkpoint created on such a path would
prune against arbitrary scalar value.

Grouping these two into one patch, as they share the same fixes tag.

Fixes: b5dc0163d8fd ("bpf: precise scalar_value tracking")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-1-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Callback frame constructors initialize map-typed argument registers with
__mark_reg_known_zero() and then restore map_ptr. This clears map_uid,
which is the only field distinguishing inner maps that share an
inner_map_meta template.

When a timer callback invokes bpf_for_each_map_elem() on a second inner
map, both the saved first map and the second map value can reach the nested
callback as the same template with map_uid zero. bpf_timer_init() then
accepts pairing the timer from the second map with the first map.

The runtime records the first map in the timer without taking a reference.
Freeing that map does not find the timer stored in the second map, so a
later timer callback dereferences the freed map.

Copy map_uid from the same caller register as map_ptr when constructing
for-each, timer/workqueue, and task-work callback arguments. The existing
identity check can then reject mismatched inner maps while allowing a
callback value to be paired with its actual map.

Fixes: 3e8ce29850f1 ("bpf: Prevent pointer mismatch in bpf_timer_init.")
Fixes: 69c087ba6225 ("bpf: Add bpf_for_each_map_elem() helper")
Fixes: 5c8fd7e2b5b0 ("bpf: bpf task work plumbing")
Reported-by: Nicholas Carlini <npc@anthropic.com>
Suggested-by: Nicholas Carlini <npc@anthropic.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904104203.345917-8-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>