The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y git checkout FETCH_HEAD git cherry-pick -x 6a5a148aaf14747570cc634f9cdfcb0393f5617f # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2023090946-wrath-compacter-d8a5@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^.. Possible dependencies: 6a5a148aaf14 ("bpf: fix bpf_probe_read_kernel prototype mismatch") 1f9a1ea821ff ("bpf: Support new sign-extension load insns") 06accc8779c1 ("bpf: add support for open-coded iterator loops") 215bf4962f6c ("bpf: add iterator kfuncs registration and validation logic") a461f5adf177 ("bpf: generalize dynptr_get_spi to be usable for iters") d0e1ac227945 ("bpf: move kfunc_call_arg_meta higher in the file") 653ae3a874ac ("bpf: clean up visit_insn()'s instruction processing") 98ddcf389d1b ("bpf: honor env->test_state_freq flag in is_state_visited()") d54e0f6c1adf ("bpf: improve stack slot state printing") 0d80a619c113 ("bpf: allow ctx writes using BPF_ST_MEM instruction") 6fcd486b3a0a ("bpf: Refactor RCU enforcement in the verifier.") 20c09d92faee ("bpf: Introduce kptr_rcu.") 8d093b4e95a2 ("bpf: Mark cgroups and dfl_cgrp fields as trusted.") 66e3a13e7c2c ("bpf: Add bpf_dynptr_slice and bpf_dynptr_slice_rdwr") 05421aecd4ed ("bpf: Add xdp dynptrs") b5964b968ac6 ("bpf: Add skb dynptrs") d96d937d7c5c ("bpf: Add __uninit kfunc annotation") 485ec51ef976 ("bpf: Refactor verifier dynptr into get_dynptr_arg_reg") 8357b366cbb0 ("bpf: Define no-ops for externally called bpf dynptr functions") 1d18feb2c915 ("bpf: Allow initializing dynptrs in kfuncs") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 6a5a148aaf14747570cc634f9cdfcb0393f5617f Mon Sep 17 00:00:00 2001 From: Arnd Bergmann <arnd@xxxxxxxx> Date: Tue, 1 Aug 2023 13:13:58 +0200 Subject: [PATCH] bpf: fix bpf_probe_read_kernel prototype mismatch bpf_probe_read_kernel() has a __weak definition in core.c and another definition with an incompatible prototype in kernel/trace/bpf_trace.c, when CONFIG_BPF_EVENTS is enabled. Since the two are incompatible, there cannot be a shared declaration in a header file, but the lack of a prototype causes a W=1 warning: kernel/bpf/core.c:1638:12: error: no previous prototype for 'bpf_probe_read_kernel' [-Werror=missing-prototypes] On 32-bit architectures, the local prototype u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr) passes arguments in other registers as the one in bpf_trace.c BPF_CALL_3(bpf_probe_read_kernel, void *, dst, u32, size, const void *, unsafe_ptr) which uses 64-bit arguments in pairs of registers. As both versions of the function are fairly simple and only really differ in one line, just move them into a header file as an inline function that does not add any overhead for the bpf_trace.c callers and actually avoids a function call for the other one. Cc: stable@xxxxxxxxxxxxxxx Link: https://lore.kernel.org/all/ac25cb0f-b804-1649-3afb-1dc6138c2716@xxxxxxxxxxxxx/ Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Acked-by: Yonghong Song <yonghong.song@xxxxxxxxx> Link: https://lore.kernel.org/r/20230801111449.185301-1-arnd@xxxxxxxxxx Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx> diff --git a/include/linux/bpf.h b/include/linux/bpf.h index ceaa8c23287f..abe75063630b 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2661,6 +2661,18 @@ static inline void bpf_dynptr_set_rdonly(struct bpf_dynptr_kern *ptr) } #endif /* CONFIG_BPF_SYSCALL */ +static __always_inline int +bpf_probe_read_kernel_common(void *dst, u32 size, const void *unsafe_ptr) +{ + int ret = -EFAULT; + + if (IS_ENABLED(CONFIG_BPF_EVENTS)) + ret = copy_from_kernel_nofault(dst, unsafe_ptr, size); + if (unlikely(ret < 0)) + memset(dst, 0, size); + return ret; +} + void __bpf_free_used_btfs(struct bpf_prog_aux *aux, struct btf_mod_pair *used_btfs, u32 len); diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index baccdec22f19..0f8f036d8bd1 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1650,12 +1650,6 @@ bool bpf_opcode_in_insntable(u8 code) } #ifndef CONFIG_BPF_JIT_ALWAYS_ON -u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr) -{ - memset(dst, 0, size); - return -EFAULT; -} - /** * ___bpf_prog_run - run eBPF program on a given context * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers @@ -2066,8 +2060,8 @@ static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn) DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ CONT; \ LDX_PROBE_MEM_##SIZEOP: \ - bpf_probe_read_kernel(&DST, sizeof(SIZE), \ - (const void *)(long) (SRC + insn->off)); \ + bpf_probe_read_kernel_common(&DST, sizeof(SIZE), \ + (const void *)(long) (SRC + insn->off)); \ DST = *((SIZE *)&DST); \ CONT; @@ -2082,7 +2076,7 @@ static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn) DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ CONT; \ LDX_PROBE_MEMSX_##SIZEOP: \ - bpf_probe_read_kernel(&DST, sizeof(SIZE), \ + bpf_probe_read_kernel_common(&DST, sizeof(SIZE), \ (const void *)(long) (SRC + insn->off)); \ DST = *((SIZE *)&DST); \ CONT; diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index c92eb8c6ff08..83bde2475ae5 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -223,17 +223,6 @@ const struct bpf_func_proto bpf_probe_read_user_str_proto = { .arg3_type = ARG_ANYTHING, }; -static __always_inline int -bpf_probe_read_kernel_common(void *dst, u32 size, const void *unsafe_ptr) -{ - int ret; - - ret = copy_from_kernel_nofault(dst, unsafe_ptr, size); - if (unlikely(ret < 0)) - memset(dst, 0, size); - return ret; -} - BPF_CALL_3(bpf_probe_read_kernel, void *, dst, u32, size, const void *, unsafe_ptr) {
