From: Quentin Casasnovas <quentin.casasnovas@oracle.com>
To: Rusty Russell <rusty@rustcorp.com.au>,
Guenter Roeck <linux@roeck-us.net>
Cc: lkml <linux-kernel@vger.kernel.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
linux-next <linux-next@vger.kernel.org>
Subject: [PATCH 1/2] modpost: fix inverted logic in is_extable_fault_address().
Date: Wed, 15 Apr 2015 10:54:37 +0200 [thread overview]
Message-ID: <1429088078-23827-2-git-send-email-quentin.casasnovas@oracle.com> (raw)
In-Reply-To: <1429088078-23827-1-git-send-email-quentin.casasnovas@oracle.com>
As Guenter pointed out, we want to assert that extable_entry_size has been
discovered and not the other way around. Moreover, this sanity check is
only valid when we're not dealing with the first relocation in __ex_table,
since we have not discovered the extable entry size at that point.
This was leading to a divide-by-zero on some architectures and make the
build fail.
Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
CC: Rusty Russell <rusty@rustcorp.com.au>
---
scripts/mod/modpost.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 22dbc60..93bb87d 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -1529,7 +1529,12 @@ static void find_extable_entry_size(const char* const sec, const Elf_Rela* r,
}
static inline bool is_extable_fault_address(Elf_Rela *r)
{
- if (!extable_entry_size == 0)
+ /*
+ * extable_entry_size is only discovered after we've handled the
+ * _second_ relocation in __ex_table, so only abort when we're not
+ * handling the first reloc and extable_entry_size is zero.
+ */
+ if (r->r_offset && extable_entry_size == 0)
fatal("extable_entry size hasn't been discovered!\n");
return ((r->r_offset == 0) ||
--
2.0.5
next prev parent reply other threads:[~2015-04-15 8:52 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-14 8:42 linux-next: Tree for Apr 14 Stephen Rothwell
2015-04-14 16:11 ` linux-next: Tree for Apr 14 (crash due to modpost patch) Guenter Roeck
2015-04-14 16:36 ` Quentin Casasnovas
2015-04-14 16:50 ` Guenter Roeck
2015-04-15 8:54 ` [PATCH 0/2] Tentative fix for the divide-by-zero on score/paris/ Quentin Casasnovas
2015-04-15 8:54 ` Quentin Casasnovas [this message]
2015-04-15 8:54 ` [PATCH 2/2] modpost: fix extable entry size calculation Quentin Casasnovas
2015-04-15 13:26 ` [PATCH 0/2] Tentative fix for the divide-by-zero on score/paris/ Guenter Roeck
2015-04-15 13:46 ` Quentin Casasnovas
2015-04-15 15:31 ` Guenter Roeck
2015-04-15 16:49 ` Quentin Casasnovas
2015-04-15 21:19 ` Quentin Casasnovas
2015-04-15 21:32 ` Guenter Roeck
2015-04-16 1:43 ` Guenter Roeck
2015-04-16 3:49 ` Rusty Russell
2015-04-16 8:21 ` Quentin Casasnovas
2015-04-16 12:47 ` Guenter Roeck
2015-04-16 13:58 ` Quentin Casasnovas
2015-04-18 5:52 ` Guenter Roeck
2015-04-19 11:47 ` Quentin Casasnovas
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