函数逻辑报告

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:kernel\bpf\verifier.c Create Date:2022-07-27 14:10:17
Last Modify:2022-05-19 20:02:10 Copyright©Brick
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函数名称：Parentage chain of this register (or stack slot) should take care of all* issues like callee-saved registers, stack slot allocation time, etc.

函数原型：static int mark_reg_read(struct bpf_verifier_env *env, const struct bpf_reg_state *state, struct bpf_reg_state *parent, u8 flag)

返回类型：int

参数：

类型参数名称
struct bpf_verifier_env *env
const struct bpf_reg_state *state
struct bpf_reg_state *parent
u8flag
1266  writes等于parent恒等于 parentage chain for liveness checking
1267  cnt等于0
1269  当parent循环
1271  如果writes且live按位与g was written first, screening off later reads 则退出
1273  如果live按位与liveness won't be updating this register anymore 则
1274  verbose(env, "verifier BUG type %s var_off %lld off %d\n", string representation of 'enum bpf_reg_type' [ Ordering of fields matters. See states_equal() ], value, Fixed part of pointer offset, pointer types only )
1277  返回:负EFAULT
1282  如果live按位与REG_LIVE_READ的值恒等于flag或live按位与likewise, but full 64-bit content matters 则退出
1295  live或等于flag
1297  如果flag恒等于likewise, but full 64-bit content matters 则live与等于g was read, so we're sensitive to initial value 的反
1299  state等于parent
1300  parent等于 parentage chain for liveness checking
1301  writes = true
1302  cnt自加
1305  如果longest register parentage chain walked for liveness marking 小于cnt则longest register parentage chain walked for liveness marking 等于cnt
1307  返回:0
调用者
名称描述
check_reg_arg
check_stack_read
check_stack_boundarywhen register 'regno' is passed into function that will read 'access_size'* bytes from that pointer, make sure that it's within stack boundary* and all elements of stack are initialized
propagate_liveness_regReturn 0 if no propagation happened. Return negative error code if error* happened. Otherwise, return the propagated bit.