Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932111AbbDOIxX (ORCPT ); Wed, 15 Apr 2015 04:53:23 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:39921 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754134AbbDOIwd (ORCPT ); Wed, 15 Apr 2015 04:52:33 -0400 From: Quentin Casasnovas To: Rusty Russell , Guenter Roeck Cc: lkml , Stephen Rothwell , linux-next Subject: [PATCH 2/2] modpost: fix extable entry size calculation. Date: Wed, 15 Apr 2015 10:54:38 +0200 Message-Id: <1429088078-23827-3-git-send-email-quentin.casasnovas@oracle.com> X-Mailer: git-send-email 2.0.5 In-Reply-To: <1429088078-23827-1-git-send-email-quentin.casasnovas@oracle.com> References: <20150414165000.GA19434@roeck-us.net> <1429088078-23827-1-git-send-email-quentin.casasnovas@oracle.com> X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3307 Lines: 81 As Guenter pointed out, we were never really calculating the extable entry size because the pointer arithmetic was simply wrong. We want to check we're handling the second relocation in __ex_table to infer an entry size, but we were using (void*) pointers instead of Elf_Rel[a]* ones. This fixes the problem by moving that check in the caller (since we can deal with different types of relocations) and add is_second_extable_reloc() to make the whole thing more readable. Signed-off-by: Quentin Casasnovas Reported-by: Guenter Roeck CC: Rusty Russell --- scripts/mod/modpost.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 93bb87d..fd94977 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1511,8 +1511,7 @@ static int is_executable_section(struct elf_info* elf, unsigned int section_inde * to know the sizeof(struct exception_table_entry) for the target architecture. */ static unsigned int extable_entry_size = 0; -static void find_extable_entry_size(const char* const sec, const Elf_Rela* r, - const void* start, const void* cur) +static void find_extable_entry_size(const char* const sec, const Elf_Rela* r) { /* * If we're currently checking the second relocation within __ex_table, @@ -1523,10 +1522,10 @@ static void find_extable_entry_size(const char* const sec, const Elf_Rela* r, * seems to go with different sized types. Not pretty but better than * hard-coding the size for every architecture.. */ - if (!extable_entry_size && cur == start + 1 && - strcmp("__ex_table", sec) == 0) + if (!extable_entry_size) extable_entry_size = r->r_offset * 2; } + static inline bool is_extable_fault_address(Elf_Rela *r) { /* @@ -1541,6 +1540,9 @@ static inline bool is_extable_fault_address(Elf_Rela *r) (r->r_offset % extable_entry_size == 0)); } +#define is_second_extable_reloc(Start, Cur, Sec) \ + (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0)) + static void report_extable_warnings(const char* modname, struct elf_info* elf, const struct sectioncheck* const mismatch, Elf_Rela* r, Elf_Sym* sym, @@ -1769,7 +1771,8 @@ static void section_rela(const char *modname, struct elf_info *elf, /* Skip special sections */ if (is_shndx_special(sym->st_shndx)) continue; - find_extable_entry_size(fromsec, &r, start, rela); + if (is_second_extable_reloc(start, rela, fromsec)) + find_extable_entry_size(fromsec, &r); check_section_mismatch(modname, elf, &r, sym, fromsec); } } @@ -1828,7 +1831,8 @@ static void section_rel(const char *modname, struct elf_info *elf, /* Skip special sections */ if (is_shndx_special(sym->st_shndx)) continue; - find_extable_entry_size(fromsec, &r, start, rel); + if (is_second_extable_reloc(start, rel, fromsec)) + find_extable_entry_size(fromsec, &r); check_section_mismatch(modname, elf, &r, sym, fromsec); } } -- 2.0.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/