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| author | Aaro Koskinen <aaro.koskinen@nsn.com> | 2014-07-22 14:51:08 +0300 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2014-09-17 16:55:07 +0200 |
| commit | 1e1c3a21579aa9ea0429b69165caef77cca27f7e (patch) | |
| tree | 0f03f1508da1a5536fd7ccbda3205636edad88c3 /arch/mips | |
| parent | 6540a038754f78f73075f906ce42c04f84297e3e (diff) | |
| download | lwn-1e1c3a21579aa9ea0429b69165caef77cca27f7e.tar.gz lwn-1e1c3a21579aa9ea0429b69165caef77cca27f7e.zip | |
MIPS: OCTEON: make get_system_type() thread-safe
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 <aaro.koskinen@nsn.com>
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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'arch/mips')
| -rw-r--r-- | arch/mips/cavium-octeon/setup.c | 18 |
1 files 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) |