queue-6.6/modpost-do-not-make-find_tosym-return-null.patch

   1 From 7a195340722526f1bf5f2278d5357bf3154e3b98 Mon Sep 17 00:00:00 2001
   2 From: Sasha Levin <sashal@kernel.org>
   3 Date: Sat, 23 Mar 2024 20:45:11 +0900
   4 Subject: modpost: do not make find_tosym() return NULL
   5
   6 From: Masahiro Yamada <masahiroy@kernel.org>
   7
   8 [ Upstream commit 1102f9f85bf66b1a7bd6a40afb40efbbe05dfc05 ]
   9
  10 As mentioned in commit 397586506c3d ("modpost: Add '.ltext' and
  11 '.ltext.*' to TEXT_SECTIONS"), modpost can result in a segmentation
  12 fault due to a NULL pointer dereference in default_mismatch_handler().
  13
  14 find_tosym() can return the original symbol pointer instead of NULL
  15 if a better one is not found.
  16
  17 This fixes the reported segmentation fault.
  18
  19 Fixes: a23e7584ecf3 ("modpost: unify 'sym' and 'to' in default_mismatch_handler()")
  20 Reported-by: Nathan Chancellor <nathan@kernel.org>
  21 Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
  22 Signed-off-by: Sasha Levin <sashal@kernel.org>
  23 ---
  24  scripts/mod/modpost.c | 7 +++++--
  25  1 file changed, 5 insertions(+), 2 deletions(-)
  26
  27 diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
  28 index 66589fb4e9aef..7d53942445d75 100644
  29 --- a/scripts/mod/modpost.c
  30 +++ b/scripts/mod/modpost.c
  31 @@ -1052,6 +1052,8 @@ static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr,
  32
  33  static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym)
  34  {
  35 +       Elf_Sym *new_sym;
  36 +
  37         /* If the supplied symbol has a valid name, return it */
  38         if (is_valid_name(elf, sym))
  39                 return sym;
  40 @@ -1060,8 +1062,9 @@ static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym)
  41          * Strive to find a better symbol name, but the resulting name may not
  42          * match the symbol referenced in the original code.
  43          */
  44 -       return symsearch_find_nearest(elf, addr, get_secindex(elf, sym),
  45 -                                     true, 20);
  46 +       new_sym = symsearch_find_nearest(elf, addr, get_secindex(elf, sym),
  47 +                                        true, 20);
  48 +       return new_sym ? new_sym : sym;
  49  }
  50
  51  static bool is_executable_section(struct elf_info *elf, unsigned int secndx)
  52 --
  53 2.43.0
  54