Commit 0c182ac2 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'objtool-core-2024-07-16' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull objtool updates from Ingo Molnar:

 - Fix bug that caused objtool to confuse certain memory ops added by
   KASAN instrumentation as stack accesses

 - Various faddr2line optimizations

 - Improve error messages

* tag 'objtool-core-2024-07-16' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool/x86: objtool can confuse memory and stack access
  objtool: Use "action" in error message to be consistent with help
  scripts/faddr2line: Check only two symbols when calculating symbol size
  scripts/faddr2line: Remove call to addr2line from find_dir_prefix()
  scripts/faddr2line: Invoke addr2line as a single long-running process
  scripts/faddr2line: Pass --addresses argument to addr2line
  scripts/faddr2line: Check vmlinux only once
  scripts/faddr2line: Combine three readelf calls into one
  scripts/faddr2line: Reduce number of readelf calls to three
parents 151647ab 8e366d83

scripts/faddr2line

+84 −26
Original line number Diff line number Diff line
@@ -85,15 +85,17 @@ command -v ${ADDR2LINE} >/dev/null 2>&1 || die "${ADDR2LINE} isn't installed" 
# init/main.c!  This only works for vmlinux.  Otherwise it falls back to

# printing the absolute path.

find_dir_prefix() {

	local objfile=$1



	local start_kernel_addr=$(${READELF} --symbols --wide $objfile | sed 's/\[.*\]//' |

	local start_kernel_addr=$(echo "${ELF_SYMS}" | sed 's/\[.*\]//' |

		${AWK} '$8 == "start_kernel" {printf "0x%s", $2}')

	[[ -z $start_kernel_addr ]] && return



	local file_line=$(${ADDR2LINE} -e $objfile $start_kernel_addr)

	[[ -z $file_line ]] && return

	run_addr2line ${start_kernel_addr} ""

	[[ -z $ADDR2LINE_OUT ]] && return



	local file_line=${ADDR2LINE_OUT#* at }

	if [[ -z $file_line ]] || [[ $file_line = $ADDR2LINE_OUT ]]; then

		return

	fi

	local prefix=${file_line%init/main.c:*}

	if [[ -z $prefix ]] || [[ $prefix = $file_line ]]; then

		return
@@ -103,6 +105,71 @@ find_dir_prefix() { 
	return 0

}



run_readelf() {

	local objfile=$1

	local out=$(${READELF} --file-header --section-headers --symbols --wide $objfile)



	# This assumes that readelf first prints the file header, then the section headers, then the symbols.

	# Note: It seems that GNU readelf does not prefix section headers with the "There are X section headers"

	# line when multiple options are given, so let's also match with the "Section Headers:" line.

	ELF_FILEHEADER=$(echo "${out}" | sed -n '/There are [0-9]* section headers, starting at offset\|Section Headers:/q;p')

	ELF_SECHEADERS=$(echo "${out}" | sed -n '/There are [0-9]* section headers, starting at offset\|Section Headers:/,$p' | sed -n '/Symbol table .* contains [0-9]* entries:/q;p')

	ELF_SYMS=$(echo "${out}" | sed -n '/Symbol table .* contains [0-9]* entries:/,$p')

}



check_vmlinux() {

	# vmlinux uses absolute addresses in the section table rather than

	# section offsets.

	IS_VMLINUX=0

	local file_type=$(echo "${ELF_FILEHEADER}" |

		${AWK} '$1 == "Type:" { print $2; exit }')

	if [[ $file_type = "EXEC" ]] || [[ $file_type == "DYN" ]]; then

		IS_VMLINUX=1

	fi

}



init_addr2line() {

	local objfile=$1



	check_vmlinux



	ADDR2LINE_ARGS="--functions --pretty-print --inlines --addresses --exe=$objfile"

	if [[ $IS_VMLINUX = 1 ]]; then

		# If the executable file is vmlinux, we don't pass section names to

		# addr2line, so we can launch it now as a single long-running process.

		coproc ADDR2LINE_PROC (${ADDR2LINE} ${ADDR2LINE_ARGS})

	fi

}



run_addr2line() {

	local addr=$1

	local sec_name=$2



	if [[ $IS_VMLINUX = 1 ]]; then

		# We send to the addr2line process: (1) the address, then (2) a sentinel

		# value, i.e., something that can't be interpreted as a valid address

		# (i.e., ","). This causes addr2line to write out: (1) the answer for

		# our address, then (2) either "?? ??:0" or "0x0...0: ..." (if

		# using binutils' addr2line), or "," (if using LLVM's addr2line).

		echo ${addr} >& "${ADDR2LINE_PROC[1]}"

		echo "," >& "${ADDR2LINE_PROC[1]}"

		local first_line

		read -r first_line <& "${ADDR2LINE_PROC[0]}"

		ADDR2LINE_OUT=$(echo "${first_line}" | sed 's/^0x[0-9a-fA-F]*: //')

		while read -r line <& "${ADDR2LINE_PROC[0]}"; do

			if [[ "$line" == "?? ??:0" ]] || [[ "$line" == "," ]] || [[ $(echo "$line" | ${GREP} "^0x00*: ") ]]; then

				break

			fi

			ADDR2LINE_OUT+=$'\n'$(echo "$line" | sed 's/^0x[0-9a-fA-F]*: //')

		done

	else

		# Run addr2line as a single invocation.

		local sec_arg

		[[ -z $sec_name ]] && sec_arg="" || sec_arg="--section=${sec_name}"

		ADDR2LINE_OUT=$(${ADDR2LINE} ${ADDR2LINE_ARGS} ${sec_arg} ${addr} | sed 's/^0x[0-9a-fA-F]*: //')

	fi

}



__faddr2line() {

	local objfile=$1

	local func_addr=$2
@@ -113,8 +180,6 @@ __faddr2line() { 
	local func_offset=${func_addr#*+}

	func_offset=${func_offset%/*}

	local user_size=

	local file_type

	local is_vmlinux=0

	[[ $func_addr =~ "/" ]] && user_size=${func_addr#*/}



	if [[ -z $sym_name ]] || [[ -z $func_offset ]] || [[ $sym_name = $func_addr ]]; then
@@ -123,14 +188,6 @@ __faddr2line() { 
		return

	fi



	# vmlinux uses absolute addresses in the section table rather than

	# section offsets.

	local file_type=$(${READELF} --file-header $objfile |

		${AWK} '$1 == "Type:" { print $2; exit }')

	if [[ $file_type = "EXEC" ]] || [[ $file_type == "DYN" ]]; then

		is_vmlinux=1

	fi



	# Go through each of the object's symbols which match the func name.

	# In rare cases there might be duplicates, in which case we print all

	# matches.
@@ -143,8 +200,7 @@ __faddr2line() { 
		local sec_name



		# Get the section size:

		sec_size=$(${READELF} --section-headers --wide $objfile |

			sed 's/\[ /\[/' |

		sec_size=$(echo "${ELF_SECHEADERS}" | sed 's/\[ /\[/' |

			${AWK} -v sec=$sym_sec '$1 == "[" sec "]" { print "0x" $6; exit }')



		if [[ -z $sec_size ]]; then
@@ -154,8 +210,7 @@ __faddr2line() { 
		fi



		# Get the section name:

		sec_name=$(${READELF} --section-headers --wide $objfile |

			sed 's/\[ /\[/' |

		sec_name=$(echo "${ELF_SECHEADERS}" | sed 's/\[ /\[/' |

			${AWK} -v sec=$sym_sec '$1 == "[" sec "]" { print $2; exit }')



		if [[ -z $sec_name ]]; then
@@ -197,7 +252,7 @@ __faddr2line() { 
				found=2

				break

			fi

		done < <(${READELF} --symbols --wide $objfile | sed 's/\[.*\]//' | ${AWK} -v sec=$sym_sec '$7 == sec' | sort --key=2)

		done < <(echo "${ELF_SYMS}" | sed 's/\[.*\]//' | ${AWK} -v sec=$sym_sec '$7 == sec' | sort --key=2 | ${GREP} -A1 --no-group-separator " ${sym_name}$")



		if [[ $found = 0 ]]; then

			warn "can't find symbol: sym_name: $sym_name sym_sec: $sym_sec sym_addr: $sym_addr sym_elf_size: $sym_elf_size"
@@ -249,9 +304,8 @@ __faddr2line() { 


		# Pass section address to addr2line and strip absolute paths

		# from the output:

		local args="--functions --pretty-print --inlines --exe=$objfile"

		[[ $is_vmlinux = 0 ]] && args="$args --section=$sec_name"

		local output=$(${ADDR2LINE} $args $addr | sed "s; $dir_prefix\(\./\)*; ;")

		run_addr2line $addr $sec_name

		local output=$(echo "${ADDR2LINE_OUT}" | sed "s; $dir_prefix\(\./\)*; ;")

		[[ -z $output ]] && continue



		# Default output (non --list):
@@ -278,7 +332,7 @@ __faddr2line() { 


		DONE=1



	done < <(${READELF} --symbols --wide $objfile | sed 's/\[.*\]//' | ${AWK} -v fn=$sym_name '$8 == fn')

	done < <(echo "${ELF_SYMS}" | sed 's/\[.*\]//' | ${AWK} -v fn=$sym_name '$8 == fn')

}



[[ $# -lt 2 ]] && usage
@@ -291,10 +345,14 @@ LIST=0 
[[ ! -f $objfile ]] && die "can't find objfile $objfile"

shift



${READELF} --section-headers --wide $objfile | ${GREP} -q '\.debug_info' || die "CONFIG_DEBUG_INFO not enabled"

run_readelf $objfile



echo "${ELF_SECHEADERS}" | ${GREP} -q '\.debug_info' || die "CONFIG_DEBUG_INFO not enabled"



init_addr2line $objfile



DIR_PREFIX=supercalifragilisticexpialidocious

find_dir_prefix $objfile

find_dir_prefix



FIRST=1

while [[ $# -gt 0 ]]; do

tools/objtool/arch/x86/decode.c

+7 −1
Original line number Diff line number Diff line
@@ -125,8 +125,14 @@ bool arch_pc_relative_reloc(struct reloc *reloc) 
#define is_RIP()   ((modrm_rm & 7) == CFI_BP && modrm_mod == 0)

#define have_SIB() ((modrm_rm & 7) == CFI_SP && mod_is_mem())



/*

 * Check the ModRM register. If there is a SIB byte then check with

 * the SIB base register. But if the SIB base is 5 (i.e. CFI_BP) and

 * ModRM mod is 0 then there is no base register.

 */

#define rm_is(reg) (have_SIB() ? \

		    sib_base == (reg) && sib_index == CFI_SP : \

		    sib_base == (reg) && sib_index == CFI_SP && \

		    (sib_base != CFI_BP || modrm_mod != 0) :	\

		    modrm_rm == (reg))



#define rm_is_mem(reg)	(mod_is_mem() && !is_RIP() && rm_is(reg))

tools/objtool/builtin-check.c

+2 −2
Original line number Diff line number Diff line
@@ -144,7 +144,7 @@ static bool opts_valid(void) 
	    opts.static_call		||

	    opts.uaccess) {

		if (opts.dump_orc) {

			ERROR("--dump can't be combined with other options");

			ERROR("--dump can't be combined with other actions");

			return false;

		}
@@ -159,7 +159,7 @@ static bool opts_valid(void) 
	if (opts.dump_orc)

		return true;



	ERROR("At least one command required");

	ERROR("At least one action required");

	return false;

}