Fix: Sleeping function called from invalid context

It affects system call instrumentation for accept, accept4 and connect,
only on the x86-64 architecture.

We need to use the LTTng accessing functions to touch user-space memory,
which take care of disabling the page fault handler, so we don't preempt
while in preempt-off context (tracepoints disable preemption).

Fixes #1111

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/instrumentation/syscalls/headers/x86-64-syscalls-3.10.0-rc7_pointers_override.h b/instrumentation/syscalls/headers/x86-64-syscalls-3.10.0-rc7_pointers_override.h
index 5e910049583e01f1dc217ea831749f0a121fbabc..6bf5291c8e470a5145432b3d3235a457d404a87b 100644 (file)
--- a/instrumentation/syscalls/headers/x86-64-syscalls-3.10.0-rc7_pointers_override.h
+++ b/instrumentation/syscalls/headers/x86-64-syscalls-3.10.0-rc7_pointers_override.h
@@ -2,7 +2,7 @@
 
 #define OVERRIDE_64_connect
 SC_LTTNG_TRACEPOINT_EVENT_CODE(connect,
-       TP_PROTO(sc_exit(long ret,) int fd, struct sockaddr * uservaddr, int addrlen),
+       TP_PROTO(sc_exit(long ret,) int fd, struct sockaddr __user * uservaddr, int addrlen),
        TP_ARGS(sc_exit(ret,) fd, uservaddr, addrlen),
        TP_locvar(
                __typeof__(uservaddr->sa_family) sa_family;
@@ -16,21 +16,28 @@ SC_LTTNG_TRACEPOINT_EVENT_CODE(connect,
                        memset(tp_locvar, 0, sizeof(*tp_locvar));
                        if (addrlen < sizeof(tp_locvar->sa_family))
                                goto skip_code;
-                       (void) get_user(tp_locvar->sa_family, &uservaddr->sa_family);
+                       (void) lib_ring_buffer_copy_from_user_check_nofault(&tp_locvar->sa_family,
+                                       &uservaddr->sa_family, sizeof(tp_locvar->sa_family));
                        switch (tp_locvar->sa_family) {
                        case AF_INET:
                                if (addrlen < sizeof(struct sockaddr_in))
                                        goto skip_code;
-                               (void) get_user(tp_locvar->dport, &((struct sockaddr_in *) uservaddr)->sin_port);
-                               (void) get_user(tp_locvar->v4addr, &((struct sockaddr_in *) uservaddr)->sin_addr.s_addr);
+                               (void) lib_ring_buffer_copy_from_user_check_nofault(&tp_locvar->dport,
+                                               &((struct sockaddr_in __user *) uservaddr)->sin_port,
+                                               sizeof(tp_locvar->dport));
+                               (void) lib_ring_buffer_copy_from_user_check_nofault(&tp_locvar->v4addr,
+                                               &((struct sockaddr_in __user *) uservaddr)->sin_addr.s_addr,
+                                               sizeof(tp_locvar->v4addr));
                                tp_locvar->v4addr_len = 4;
                                break;
                        case AF_INET6:
                                if (addrlen < sizeof(struct sockaddr_in6))
                                        goto skip_code;
-                               (void) get_user(tp_locvar->dport, &((struct sockaddr_in6 *) uservaddr)->sin6_port);
-                               if (copy_from_user(tp_locvar->v6addr,
-                                               &((struct sockaddr_in6 *) uservaddr)->sin6_addr.in6_u.u6_addr8,
+                               (void) lib_ring_buffer_copy_from_user_check_nofault(&tp_locvar->dport,
+                                               &((struct sockaddr_in6 __user *) uservaddr)->sin6_port,
+                                               sizeof(tp_locvar->dport));
+                               if (lib_ring_buffer_copy_from_user_check_nofault(tp_locvar->v6addr,
+                                               &((struct sockaddr_in6 __user *) uservaddr)->sin6_addr.in6_u.u6_addr8,
                                                sizeof(tp_locvar->v6addr)))
                                        memset(tp_locvar->v6addr, 0, sizeof(tp_locvar->v6addr));
                                tp_locvar->v6addr_len = 8;
@@ -63,26 +70,34 @@ SC_LTTNG_TRACEPOINT_EVENT_CODE(connect,
 #define LTTNG_SYSCALL_ACCEPT_code_pre                                                                                  \
        sc_inout(                                                                                                       \
                memset(tp_locvar, 0, sizeof(*tp_locvar));                                                               \
-               (void) get_user(tp_locvar->uaddr_len, upeer_addrlen);                                                   \
+               (void) lib_ring_buffer_copy_from_user_check_nofault(&tp_locvar->uaddr_len,                              \
+                               upeer_addrlen, sizeof(tp_locvar->uaddr_len));                                           \
        )                                                                                                               \
        sc_out(                                                                                                         \
                if (tp_locvar->uaddr_len < sizeof(tp_locvar->sa_family))                                                \
                        goto skip_code;                                                                                 \
-               (void) get_user(tp_locvar->sa_family, &upeer_sockaddr->sa_family);                                      \
+               (void) lib_ring_buffer_copy_from_user_check_nofault(&tp_locvar->sa_family,                              \
+                               &upeer_sockaddr->sa_family, sizeof(tp_locvar->sa_family));                              \
                switch (tp_locvar->sa_family) {                                                                         \
                case AF_INET:                                                                                           \
                        if (tp_locvar->uaddr_len < sizeof(struct sockaddr_in))                                          \
                                goto skip_code;                                                                         \
-                       (void) get_user(tp_locvar->sport, &((struct sockaddr_in *) upeer_sockaddr)->sin_port);          \
-                       (void) get_user(tp_locvar->v4addr, &((struct sockaddr_in *) upeer_sockaddr)->sin_addr.s_addr);  \
+                       (void) lib_ring_buffer_copy_from_user_check_nofault(&tp_locvar->sport,                          \
+                                       &((struct sockaddr_in __user *) upeer_sockaddr)->sin_port,                      \
+                                       sizeof(tp_locvar->sport));                                                      \
+                       (void) lib_ring_buffer_copy_from_user_check_nofault(&tp_locvar->v4addr,                         \
+                                       &((struct sockaddr_in __user *) upeer_sockaddr)->sin_addr.s_addr,               \
+                                       sizeof(tp_locvar->v4addr));                                                     \
                        tp_locvar->v4addr_len = 4;                                                                      \
                        break;                                                                                          \
                case AF_INET6:                                                                                          \
                        if (tp_locvar->uaddr_len < sizeof(struct sockaddr_in6))                                         \
                                goto skip_code;                                                                         \
-                       (void) get_user(tp_locvar->sport, &((struct sockaddr_in6 *) upeer_sockaddr)->sin6_port);        \
-                       if (copy_from_user(tp_locvar->v6addr,                                                           \
-                                       &((struct sockaddr_in6 *) upeer_sockaddr)->sin6_addr.in6_u.u6_addr8,            \
+                       (void) lib_ring_buffer_copy_from_user_check_nofault(&tp_locvar->sport,                          \
+                                       &((struct sockaddr_in6 __user *) upeer_sockaddr)->sin6_port,                    \
+                                       sizeof(tp_locvar->sport));                                                      \
+                       if (lib_ring_buffer_copy_from_user_check_nofault(tp_locvar->v6addr,                             \
+                                       &((struct sockaddr_in6 __user *) upeer_sockaddr)->sin6_addr.in6_u.u6_addr8,     \
                                        sizeof(tp_locvar->v6addr)))                                                     \
                                memset(tp_locvar->v6addr, 0, sizeof(tp_locvar->v6addr));                                \
                        tp_locvar->v6addr_len = 8;                                                                      \
@@ -93,7 +108,7 @@ SC_LTTNG_TRACEPOINT_EVENT_CODE(connect,
 
 #define OVERRIDE_64_accept
 SC_LTTNG_TRACEPOINT_EVENT_CODE(accept,
-       TP_PROTO(sc_exit(long ret,) int fd, struct sockaddr * upeer_sockaddr, int * upeer_addrlen),
+       TP_PROTO(sc_exit(long ret,) int fd, struct sockaddr __user * upeer_sockaddr, int __user * upeer_addrlen),
        TP_ARGS(sc_exit(ret,) fd, upeer_sockaddr, upeer_addrlen),
        TP_locvar(
                LTTNG_SYSCALL_ACCEPT_locvar
@@ -116,7 +131,7 @@ SC_LTTNG_TRACEPOINT_EVENT_CODE(accept,
 
 #define OVERRIDE_64_accept4
 SC_LTTNG_TRACEPOINT_EVENT_CODE(accept4,
-       TP_PROTO(sc_exit(long ret,) int fd, struct sockaddr * upeer_sockaddr, int * upeer_addrlen, int flags),
+       TP_PROTO(sc_exit(long ret,) int fd, struct sockaddr __user * upeer_sockaddr, int __user * upeer_addrlen, int flags),
        TP_ARGS(sc_exit(ret,) fd, upeer_sockaddr, upeer_addrlen, flags),
        TP_locvar(
                LTTNG_SYSCALL_ACCEPT_locvar