-stable review patch. If anyone has any objections, please let us know. ------------------ From: Thomas Gleixner The __copy_to_user_inatomic() calls in file_read_actor() and pipe_read() are broken on original i386 machines, where WP-works-ok == false, as __copy_to_user_inatomic() on such systems calls functions which might sleep and/or contain cond_resched() calls inside of a kmap_atomic() region. The original check for WP-works-ok was in access_ok(), but got moved during the 2.5 series to fix a race vs. swap. Return the number of bytes to copy in the case where we are in an atomic region, so the non atomic code pathes in file_read_actor() and pipe_read() are taken. This could be optimized to avoid the kmap_atomic by moving the check for WP-works-ok into fault_in_pages_writeable(), but this is more intrusive and can be done later. Signed-off-by: Thomas Gleixner Acked-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/i386/lib/usercopy.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/arch/i386/lib/usercopy.c +++ b/arch/i386/lib/usercopy.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include @@ -719,6 +720,14 @@ unsigned long __copy_to_user_ll(void __u #ifndef CONFIG_X86_WP_WORKS_OK if (unlikely(boot_cpu_data.wp_works_ok == 0) && ((unsigned long )to) < TASK_SIZE) { + /* + * When we are in an atomic section (see + * mm/filemap.c:file_read_actor), return the full + * length to take the slow path. + */ + if (in_atomic()) + return n; + /* * CPU does not honor the WP bit when writing * from supervisory mode, and due to preemption or SMP, -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/