Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux

ARM: 8764/1: kgdb: fix NUMREGBYTES so that gdb_regs[] is the correct size

NUMREGBYTES (which is used as the size for gdb_regs[]) is incorrectly
based on DBG_MAX_REG_NUM instead of GDB_MAX_REGS. DBG_MAX_REG_NUM
is the number of total registers, while GDB_MAX_REGS is the number
of 'unsigned longs' it takes to serialize those registers. Since
FP registers require 3 'unsigned longs' each, DBG_MAX_REG_NUM is
smaller than GDB_MAX_REGS.

This causes GDB 8.0 give the following error on connect:
"Truncated register 19 in remote 'g' packet"

This also causes the register serialization/deserialization logic
to overflow gdb_regs[], overwriting whatever follows.

Fixes: 834b2964b7ab ("kgdb,arm: fix register dump")
Cc: <stable@vger.kernel.org> # 2.6.37+
Signed-off-by: David Rivshin <drivshin@allworx.com>
Acked-by: Rabin Vincent <rabin@rab.in>
Tested-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

authored by

David Rivshin and committed by
Russell King
76ed0b80 a70c3ee3

+1 -1
+1 -1
arch/arm/include/asm/kgdb.h
··· 77 77 78 78 #define KGDB_MAX_NO_CPUS 1 79 79 #define BUFMAX 400 80 - #define NUMREGBYTES (DBG_MAX_REG_NUM << 2) 80 + #define NUMREGBYTES (GDB_MAX_REGS << 2) 81 81 #define NUMCRITREGBYTES (32 << 2) 82 82 83 83 #define _R0 0