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MIPS: OCTEON: make get_system_type() thread-safe 

get_system_type() is not thread-safe on OCTEON. It uses static data,
also more dangerous issue is that it's calling cvmx_fuse_read_byte()
every time without any synchronization. Currently it's possible to get
processes stuck looping forever in kernel simply by launching multiple
readers of /proc/cpuinfo:

	(while true; do cat /proc/cpuinfo > /dev/null; done) &
	(while true; do cat /proc/cpuinfo > /dev/null; done) &
	...

Fix by initializing the system type string only once during the early
boot.

Signed-off-by: Aaro Koskinen <aaro.koskinen@nsn.com>
Cc: stable@vger.kernel.org
Reviewed-by: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: http://patchwork.linux-mips.org/patch/7437/
Signed-off-by: James Hogan <james.hogan@imgtec.com>
This commit is contained in:
Aaro Koskinen 2014-07-22 14:51:08 +03:00 committed by Ralf Baechle
parent 56d2960958
commit 33d9a530d4
1 changed files with 13 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
arch/mips/cavium-octeon/setup.c
View File

@ -457,6 +457,18 @@ static void octeon_halt(void)
octeon_kill_core(NULL);
}
static char __read_mostly octeon_system_type[80];
static int __init init_octeon_system_type(void)
{
snprintf(octeon_system_type, sizeof(octeon_system_type), "%s (%s)",
cvmx_board_type_to_string(octeon_bootinfo->board_type),
octeon_model_get_string(read_c0_prid()));
return 0;
}
early_initcall(init_octeon_system_type);
/**
* Return a string representing the system type
*
@ -464,11 +476,7 @@ static void octeon_halt(void)
*/
const char *octeon_board_type_string(void)
{
static char name[80];
sprintf(name, "%s (%s)",
cvmx_board_type_to_string(octeon_bootinfo->board_type),
octeon_model_get_string(read_c0_prid()));
return name;
return octeon_system_type;
}
const char *get_system_type(void)