From 506ada89629ec7059b96ecfb0dc7d33ece0103ca Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Fri, 4 Sep 2026 17:05:56 -0700 Subject: bpf: mark a NULL kfunc argument precise 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 Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com Signed-off-by: Alexei Starovoitov --- include/asm-generic/bitops/instrumented-atomic.h | 103 +++++++++++++++++++++++ 1 file changed, 103 insertions(+) create mode 100644 include/asm-generic/bitops/instrumented-atomic.h (limited to 'include/asm-generic/bitops/instrumented-atomic.h') diff --git a/include/asm-generic/bitops/instrumented-atomic.h b/include/asm-generic/bitops/instrumented-atomic.h new file mode 100644 index 000000000..c010d5427 --- /dev/null +++ b/include/asm-generic/bitops/instrumented-atomic.h @@ -0,0 +1,103 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * This file provides wrappers with sanitizer instrumentation for atomic bit + * operations. + * + * To use this functionality, an arch's bitops.h file needs to define each of + * the below bit operations with an arch_ prefix (e.g. arch_set_bit(), + * arch___set_bit(), etc.). + */ +#ifndef _ASM_GENERIC_BITOPS_INSTRUMENTED_ATOMIC_H +#define _ASM_GENERIC_BITOPS_INSTRUMENTED_ATOMIC_H + +#include + +/** + * set_bit - Atomically set a bit in memory + * @nr: the bit to set + * @addr: the address to start counting from + * + * This is a relaxed atomic operation (no implied memory barriers). + * + * Note that @nr may be almost arbitrarily large; this function is not + * restricted to acting on a single-word quantity. + */ +static __always_inline void set_bit(long nr, volatile unsigned long *addr) +{ + instrument_atomic_write(addr + BIT_WORD(nr), sizeof(long)); + arch_set_bit(nr, addr); +} + +/** + * clear_bit - Clears a bit in memory + * @nr: Bit to clear + * @addr: Address to start counting from + * + * This is a relaxed atomic operation (no implied memory barriers). + */ +static __always_inline void clear_bit(long nr, volatile unsigned long *addr) +{ + instrument_atomic_write(addr + BIT_WORD(nr), sizeof(long)); + arch_clear_bit(nr, addr); +} + +/** + * change_bit - Toggle a bit in memory + * @nr: Bit to change + * @addr: Address to start counting from + * + * This is a relaxed atomic operation (no implied memory barriers). + * + * Note that @nr may be almost arbitrarily large; this function is not + * restricted to acting on a single-word quantity. + */ +static __always_inline void change_bit(long nr, volatile unsigned long *addr) +{ + instrument_atomic_write(addr + BIT_WORD(nr), sizeof(long)); + arch_change_bit(nr, addr); +} + +/** + * test_and_set_bit - Set a bit and return its old value + * @nr: Bit to set + * @addr: Address to count from + * + * This is an atomic fully-ordered operation (implied full memory barrier). + */ +static __always_inline bool test_and_set_bit(long nr, volatile unsigned long *addr) +{ + kcsan_mb(); + instrument_atomic_read_write(addr + BIT_WORD(nr), sizeof(long)); + return arch_test_and_set_bit(nr, addr); +} + +/** + * test_and_clear_bit - Clear a bit and return its old value + * @nr: Bit to clear + * @addr: Address to count from + * + * This is an atomic fully-ordered operation (implied full memory barrier). + */ +static __always_inline bool test_and_clear_bit(long nr, volatile unsigned long *addr) +{ + kcsan_mb(); + instrument_atomic_read_write(addr + BIT_WORD(nr), sizeof(long)); + return arch_test_and_clear_bit(nr, addr); +} + +/** + * test_and_change_bit - Change a bit and return its old value + * @nr: Bit to change + * @addr: Address to count from + * + * This is an atomic fully-ordered operation (implied full memory barrier). + */ +static __always_inline bool test_and_change_bit(long nr, volatile unsigned long *addr) +{ + kcsan_mb(); + instrument_atomic_read_write(addr + BIT_WORD(nr), sizeof(long)); + return arch_test_and_change_bit(nr, addr); +} + +#endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_ATOMIC_H */ -- cgit v1.3.1