Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/li…

…nux/kernel/git/rusty/linux

Pull module updates from Rusty Russell:
 "Quentin opened a can of worms by adding extable entry checking to
  modpost, but most architectures seem fixed now.  Thanks to all
  involved.

  Last minute rebase because I noticed a "[PATCH]" had snuck into a
  commit message somehow"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  modpost: don't emit section mismatch warnings for compiler optimizations
  modpost: expand pattern matching to support substring matches
  modpost: do not try to match the SHT_NUL section.
  modpost: fix extable entry size calculation.
  modpost: fix inverted logic in is_extable_fault_address().
  modpost: handle -ffunction-sections
  modpost: Whitelist .text.fixup and .exception.text
  params: handle quotes properly for values not of form foo="bar".
  modpost: document the use of struct section_check.
  modpost: handle relocations mismatch in __ex_table.
  scripts: add check_extable.sh script.
  modpost: mismatch_handler: retrieve tosym information only when needed.
  modpost: factorize symbol pretty print in get_pretty_name().
  modpost: add handler function pointer to sectioncheck.
  modpost: add .sched.text and .kprobes.text to the TEXT_SECTIONS list.
  modpost: add strict white-listing when referencing sections.
  module: do not print allocation-fail warning on bogus user buffer size
  kernel/module.c: fix typos in message about unused symbols

kernel/module.c

@@ -387,9 +387,9 @@ static bool check_symbol(const struct symsearch *syms,
 		pr_warn("Symbol %s is marked as UNUSED, however this module is "
 			"using it.\n", fsa->name);
 		pr_warn("This symbol will go away in the future.\n");
-		pr_warn("Please evalute if this is the right api to use and if "
-			"it really is, submit a report the linux kernel "
-			"mailinglist together with submitting your code for "
+		pr_warn("Please evaluate if this is the right api to use and "
+			"if it really is, submit a report to the linux kernel "
+			"mailing list together with submitting your code for "
 			"inclusion.\n");
 	}
 #endif
@@ -2511,7 +2511,8 @@ static int copy_module_from_user(const void __user *umod, unsigned long len,
 		return err;
 
 	/* Suck in entire file: we'll want most of it. */
-	info->hdr = vmalloc(info->len);
+	info->hdr = __vmalloc(info->len,
+			GFP_KERNEL | __GFP_HIGHMEM | __GFP_NOWARN, PAGE_KERNEL);
 	if (!info->hdr)
 		return -ENOMEM;
 

kernel/params.c

@@ -173,9 +173,9 @@ static char *next_arg(char *args, char **param, char **val)
 			if (args[i-1] == '"')
 				args[i-1] = '\0';
 		}
-		if (quoted && args[i-1] == '"')
-			args[i-1] = '\0';
 	}
+	if (quoted && args[i-1] == '"')
+		args[i-1] = '\0';
 
 	if (args[i]) {
 		args[i] = '\0';

scripts/check_extable.sh

@@ -0,0 +1,146 @@
+#! /bin/bash
+# (c) 2015, Quentin Casasnovas <[email protected]>
+
+obj=$1
+
+file ${obj} | grep -q ELF || (echo "${obj} is not and ELF file." 1>&2 ; exit 0)
+
+# Bail out early if there isn't an __ex_table section in this object file.
+objdump -hj __ex_table ${obj} 2> /dev/null > /dev/null
+[ $? -ne 0 ] && exit 0
+
+white_list=.text,.fixup
+
+suspicious_relocs=$(objdump -rj __ex_table ${obj}  | tail -n +6 |
+			grep -v $(eval echo -e{${white_list}}) | awk '{print $3}')
+
+# No suspicious relocs in __ex_table, jobs a good'un
+[ -z "${suspicious_relocs}" ] && exit 0
+
+
+# After this point, something is seriously wrong since we just found out we
+# have some relocations in __ex_table which point to sections which aren't
+# white listed.  If you're adding a new section in the Linux kernel, and
+# you're expecting this section to contain code which can fault (i.e. the
+# __ex_table relocation to your new section is expected), simply add your
+# new section to the white_list variable above.  If not, you're probably
+# doing something wrong and the rest of this code is just trying to print
+# you more information about it.
+
+function find_section_offset_from_symbol()
+{
+    eval $(objdump -t ${obj} | grep ${1} | sed 's/\([0-9a-f]\+\) .\{7\} \([^ \t]\+\).*/section="\2"; section_offset="0x\1" /')
+
+    # addr2line takes addresses in hexadecimal...
+    section_offset=$(printf "0x%016x" $(( ${section_offset} + $2 )) )
+}
+
+function find_symbol_and_offset_from_reloc()
+{
+    # Extract symbol and offset from the objdump output
+    eval $(echo $reloc | sed 's/\([^+]\+\)+\?\(0x[0-9a-f]\+\)\?/symbol="\1"; symbol_offset="\2"/')
+
+    # When the relocation points to the begining of a symbol or section, it
+    # won't print the offset since it is zero.
+    if [ -z "${symbol_offset}" ]; then
+	symbol_offset=0x0
+    fi
+}
+
+function find_alt_replacement_target()
+{
+    # The target of the .altinstr_replacement is the relocation just before
+    # the .altinstr_replacement one.
+    eval $(objdump -rj .altinstructions ${obj} | grep -B1 "${section}+${section_offset}" | head -n1 | awk '{print $3}' |
+	   sed 's/\([^+]\+\)+\(0x[0-9a-f]\+\)/alt_target_section="\1"; alt_target_offset="\2"/')
+}
+
+function handle_alt_replacement_reloc()
+{
+    # This will define alt_target_section and alt_target_section_offset
+    find_alt_replacement_target ${section} ${section_offset}
+
+    echo "Error: found a reference to .altinstr_replacement in __ex_table:"
+    addr2line -fip -j ${alt_target_section} -e ${obj} ${alt_target_offset} | awk '{print "\t" $0}'
+
+    error=true
+}
+
+function is_executable_section()
+{
+    objdump -hwj ${section} ${obj} | grep -q CODE
+    return $?
+}
+
+function handle_suspicious_generic_reloc()
+{
+    if is_executable_section ${section}; then
+	# We've got a relocation to a non white listed _executable_
+	# section, print a warning so the developper adds the section to
+	# the white list or fix his code.  We try to pretty-print the file
+	# and line number where that relocation was added.
+	echo "Warning: found a reference to section \"${section}\" in __ex_table:"
+	addr2line -fip -j ${section} -e ${obj} ${section_offset} | awk '{print "\t" $0}'
+    else
+	# Something is definitively wrong here since we've got a relocation
+	# to a non-executable section, there's no way this would ever be
+	# running in the kernel.
+	echo "Error: found a reference to non-executable section \"${section}\" in __ex_table at offset ${section_offset}"
+	error=true
+    fi
+}
+
+function handle_suspicious_reloc()
+{
+    case "${section}" in
+	".altinstr_replacement")
+	    handle_alt_replacement_reloc ${section} ${section_offset}
+	    ;;
+	*)
+	    handle_suspicious_generic_reloc ${section} ${section_offset}
+	    ;;
+    esac
+}
+
+function diagnose()
+{
+
+    for reloc in ${suspicious_relocs}; do
+	# Let's find out where the target of the relocation in __ex_table
+	# is, this will define ${symbol} and ${symbol_offset}
+	find_symbol_and_offset_from_reloc ${reloc}
+
+	# When there's a global symbol at the place of the relocation,
+	# objdump will use it instead of giving us a section+offset, so
+	# let's find out which section is this symbol in and the total
+	# offset withing that section.
+	find_section_offset_from_symbol ${symbol} ${symbol_offset}
+
+	# In this case objdump was presenting us with a reloc to a symbol
+	# rather than a section. Now that we've got the actual section,
+	# we can skip it if it's in the white_list.
+	if [ -z "$( echo $section | grep -v $(eval echo -e{${white_list}}))" ]; then
+	    continue;
+	fi
+
+	# Will either print a warning if the relocation happens to be in a
+	# section we do not know but has executable bit set, or error out.
+	handle_suspicious_reloc
+    done
+}
+
+function check_debug_info() {
+    objdump -hj .debug_info ${obj} 2> /dev/null > /dev/null ||
+	echo -e "${obj} does not contain debug information, the addr2line output will be limited.\n" \
+	     "Recompile ${obj} with CONFIG_DEBUG_INFO to get a more useful output."
+}
+
+check_debug_info
+
+diagnose
+
+if [ "${error}" ]; then
+    exit 1
+fi
+
+exit 0