Without flushing the vdso data page the vdso call is working on dated or unsynced data. This resulted in problems where the clock_gettime vdso call returned a time 6 seconds later after a 3 sounds sleep, while the syscall reported a time 3 sounds later like expected. This happened very often and I got these ping results for example: root@OpenWrt:/# ping 192.168.1.255 PING 192.168.1.255 (192.168.1.255): 56 data bytes 64 bytes from 192.168.1.3: seq=0 ttl=64 time=0.688 ms 64 bytes from 192.168.1.3: seq=1 ttl=64 time=4294172.045 ms 64 bytes from 192.168.1.3: seq=2 ttl=64 time=4293968.105 ms 64 bytes from 192.168.1.3: seq=3 ttl=64 time=4294055.920 ms 64 bytes from 192.168.1.3: seq=4 ttl=64 time=4294671.913 ms The flush is now done like it is done on the arm architecture code. This was tested on a Lantiq/Intel VRX288 (MIPS BE 34Kc V5.6 CPU with two VPEs) Signed-off-by: Hauke Mehrtens <hauke@xxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> # v4.4+ --- arch/mips/kernel/vdso.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c index 975e997..78fb05e 100644 --- a/arch/mips/kernel/vdso.c +++ b/arch/mips/kernel/vdso.c @@ -20,6 +20,8 @@ #include <linux/timekeeper_internal.h> #include <asm/abi.h> +#include <asm/cacheflush.h> +#include <asm/page.h> #include <asm/vdso.h> /* Kernel-provided data used by the VDSO. */ @@ -85,6 +87,7 @@ void update_vsyscall(struct timekeeper *tk) } vdso_data_write_end(&vdso_data); + flush_dcache_page(virt_to_page(&vdso_data)); } void update_vsyscall_tz(void) @@ -93,6 +96,7 @@ void update_vsyscall_tz(void) vdso_data.tz_minuteswest = sys_tz.tz_minuteswest; vdso_data.tz_dsttime = sys_tz.tz_dsttime; } + flush_dcache_page(virt_to_page(&vdso_data)); } int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) -- 2.7.0
