3.2.65-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Pawel Moll <pawel.m...@arm.com> commit b3f207855f57b9c8f43a547a801340bb5cbc59e5 upstream. When running a 32-bit userspace on a 64-bit kernel (eg. i386 application on x86_64 kernel or 32-bit arm userspace on arm64 kernel) some of the perf ioctls must be treated with special care, as they have a pointer size encoded in the command. For example, PERF_EVENT_IOC_ID in 32-bit world will be encoded as 0x80042407, but 64-bit kernel will expect 0x80082407. In result the ioctl will fail returning -ENOTTY. This patch solves the problem by adding code fixing up the size as compat_ioctl file operation. Reported-by: Drew Richardson <drew.richard...@arm.com> Signed-off-by: Pawel Moll <pawel.m...@arm.com> Signed-off-by: Peter Zijlstra <pet...@infradead.org> Cc: Arnaldo Carvalho de Melo <a...@kernel.org> Cc: Jiri Olsa <jo...@redhat.com> Link: http://lkml.kernel.org/r/1402671812-9078-1-git-send-email-pawel.m...@arm.com Signed-off-by: Ingo Molnar <mi...@kernel.org> Cc: David Ahern <dsah...@gmail.com> [lizf: Backported to 3.4 by David Ahern] Signed-off-by: Zefan Li <lize...@huawei.com> Signed-off-by: Ben Hutchings <b...@decadent.org.uk> --- kernel/events/core.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -36,6 +36,7 @@ #include <linux/perf_event.h> #include <linux/ftrace_event.h> #include <linux/hw_breakpoint.h> +#include <linux/compat.h> #include "internal.h" @@ -3444,6 +3445,25 @@ static long perf_ioctl(struct file *file return 0; } +#ifdef CONFIG_COMPAT +static long perf_compat_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + switch (_IOC_NR(cmd)) { + case _IOC_NR(PERF_EVENT_IOC_SET_FILTER): + /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */ + if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) { + cmd &= ~IOCSIZE_MASK; + cmd |= sizeof(void *) << IOCSIZE_SHIFT; + } + break; + } + return perf_ioctl(file, cmd, arg); +} +#else +# define perf_compat_ioctl NULL +#endif + int perf_event_task_enable(void) { struct perf_event *event; @@ -3910,7 +3930,7 @@ static const struct file_operations perf .read = perf_read, .poll = perf_poll, .unlocked_ioctl = perf_ioctl, - .compat_ioctl = perf_ioctl, + .compat_ioctl = perf_compat_ioctl, .mmap = perf_mmap, .fasync = perf_fasync, }; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
