From: Aaro Koskinen <[email protected]>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
commit 608308682addfdc7b8e2aee88f0e028331d88e4d upstream.
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 <[email protected]>
Reviewed-by: Markos Chandras <[email protected]>
Patchwork: http://patchwork.linux-mips.org/patch/7437/
Signed-off-by: James Hogan <[email protected]>
Signed-off-by: Jiri Slaby <[email protected]>
---
arch/mips/cavium-octeon/setup.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/arch/mips/cavium-octeon/setup.c b/arch/mips/cavium-octeon/setup.c
index b212ae12e5ac..8a0079981cc8 100644
--- a/arch/mips/cavium-octeon/setup.c
+++ b/arch/mips/cavium-octeon/setup.c
@@ -458,6 +458,18 @@ 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
*
@@ -465,11 +477,7 @@ 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)
--
2.1.0
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