Merge branch 'for-linus' of git://one.firstfloor.org/home/andi/git/linux-2.6

* 'for-linus' of git://one.firstfloor.org/home/andi/git/linux-2.6: (156 commits)
  [PATCH] x86-64: Export smp_call_function_single
  [PATCH] i386: Clean up smp_tune_scheduling()
  [PATCH] unwinder: move .eh_frame to RODATA
  [PATCH] unwinder: fully support linker generated .eh_frame_hdr section
  [PATCH] x86-64: don't use set_irq_regs()
  [PATCH] x86-64: check vector in setup_ioapic_dest to verify if need setup_IO_APIC_irq
  [PATCH] x86-64: Make ix86 default to HIGHMEM4G instead of NOHIGHMEM
  [PATCH] i386: replace kmalloc+memset with kzalloc
  [PATCH] x86-64: remove remaining pc98 code
  [PATCH] x86-64: remove unused variable
  [PATCH] x86-64: Fix constraints in atomic_add_return()
  [PATCH] x86-64: fix asm constraints in i386 atomic_add_return
  [PATCH] x86-64: Correct documentation for bzImage protocol v2.05
  [PATCH] x86-64: replace kmalloc+memset with kzalloc in MTRR code
  [PATCH] x86-64: Fix numaq build error
  [PATCH] x86-64: include/asm-x86_64/cpufeature.h isn't a userspace header
  [PATCH] unwinder: Add debugging output to the Dwarf2 unwinder
  [PATCH] x86-64: Clarify error message in GART code
  [PATCH] x86-64: Fix interrupt race in idle callback (3rd try)
  [PATCH] x86-64: Remove unwind stack pointer alignment forcing again
  ...

Fixed conflict in include/linux/uaccess.h manually

Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 173 insertions, 45 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index 65883814864..7f2e31ba33a 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1319,7 +1319,7 @@ fork_out:
         return ERR_PTR(retval);
 }
 
-struct pt_regs * __devinit __attribute__((weak)) idle_regs(struct pt_regs *regs)
+noinline struct pt_regs * __devinit __attribute__((weak)) idle_regs(struct pt_regs *regs)
 {
         memset(regs, 0, sizeof(struct pt_regs));
         return regs;
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 62e73ce6819..b02032476dc 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -221,11 +221,7 @@ static int save_trace(struct stack_trace *trace)
         trace->skip = 3;
         trace->all_contexts = 0;
 
-        /* Make sure to not recurse in case the the unwinder needs to tak
-e          locks. */
-        lockdep_off();
         save_stack_trace(trace, NULL);
-        lockdep_on();
 
         trace->max_entries = trace->nr_entries;
 
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 758dbbf972a..8e9f00fd6d1 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -54,6 +54,7 @@ extern int proc_nr_files(ctl_table *table, int write, struct file *filp,
 
 #ifdef CONFIG_X86
 #include <asm/nmi.h>
+#include <asm/stacktrace.h>
 #endif
 
 #if defined(CONFIG_SYSCTL)
@@ -707,6 +708,14 @@ static ctl_table kern_table[] = {
                 .mode           = 0444,
                 .proc_handler   = &proc_dointvec,
         },
+        {
+                .ctl_name       = CTL_UNNUMBERED,
+                .procname       = "kstack_depth_to_print",
+                .data           = &kstack_depth_to_print,
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .proc_handler   = &proc_dointvec,
+        },
 #endif
 #if defined(CONFIG_MMU)
         {
diff --git a/kernel/unwind.c b/kernel/unwind.c
index ed0a21d4a90..09c26132924 100644
--- a/kernel/unwind.c
+++ b/kernel/unwind.c
@@ -14,11 +14,12 @@
 #include <linux/bootmem.h>
 #include <linux/sort.h>
 #include <linux/stop_machine.h>
+#include <linux/uaccess.h>
 #include <asm/sections.h>
 #include <asm/uaccess.h>
 #include <asm/unaligned.h>
 
-extern char __start_unwind[], __end_unwind[];
+extern const char __start_unwind[], __end_unwind[];
 extern const u8 __start_unwind_hdr[], __end_unwind_hdr[];
 
 #define MAX_STACK_DEPTH 8
@@ -94,6 +95,7 @@ static const struct {
 
 typedef unsigned long uleb128_t;
 typedef   signed long sleb128_t;
+#define sleb128abs __builtin_labs
 
 static struct unwind_table {
         struct {
@@ -135,6 +137,17 @@ struct unwind_state {
 
 static const struct cfa badCFA = { ARRAY_SIZE(reg_info), 1 };
 
+static unsigned unwind_debug;
+static int __init unwind_debug_setup(char *s)
+{
+        unwind_debug = simple_strtoul(s, NULL, 0);
+        return 1;
+}
+__setup("unwind_debug=", unwind_debug_setup);
+#define dprintk(lvl, fmt, args...) \
+        ((void)(lvl > unwind_debug \
+         || printk(KERN_DEBUG "unwind: " fmt "\n", ##args)))
+
 static struct unwind_table *find_table(unsigned long pc)
 {
         struct unwind_table *table;
@@ -151,7 +164,9 @@ static struct unwind_table *find_table(unsigned long pc)
 
 static unsigned long read_pointer(const u8 **pLoc,
                                   const void *end,
-                                  signed ptrType);
+                                  signed ptrType,
+                                  unsigned long text_base,
+                                  unsigned long data_base);
 
 static void init_unwind_table(struct unwind_table *table,
                               const char *name,
@@ -176,10 +191,13 @@ static void init_unwind_table(struct unwind_table *table,
         /* See if the linker provided table looks valid. */
         if (header_size <= 4
             || header_start[0] != 1
-            || (void *)read_pointer(&ptr, end, header_start[1]) != table_start
-            || header_start[2] == DW_EH_PE_omit
-            || read_pointer(&ptr, end, header_start[2]) <= 0
-            || header_start[3] == DW_EH_PE_omit)
+            || (void *)read_pointer(&ptr, end, header_start[1], 0, 0)
+               != table_start
+            || !read_pointer(&ptr, end, header_start[2], 0, 0)
+            || !read_pointer(&ptr, end, header_start[3], 0,
+                             (unsigned long)header_start)
+            || !read_pointer(&ptr, end, header_start[3], 0,
+                             (unsigned long)header_start))
                 header_start = NULL;
         table->hdrsz = header_size;
         smp_wmb();
@@ -269,7 +287,7 @@ static void __init setup_unwind_table(struct unwind_table *table,
                 ptr = (const u8 *)(fde + 2);
                 if (!read_pointer(&ptr,
                                   (const u8 *)(fde + 1) + *fde,
-                                  ptrType))
+                                  ptrType, 0, 0))
                         return;
                 ++n;
         }
@@ -279,6 +297,7 @@ static void __init setup_unwind_table(struct unwind_table *table,
 
         hdrSize = 4 + sizeof(unsigned long) + sizeof(unsigned int)
                 + 2 * n * sizeof(unsigned long);
+        dprintk(2, "Binary lookup table size for %s: %lu bytes", table->name, hdrSize);
         header = alloc(hdrSize);
         if (!header)
                 return;
@@ -303,7 +322,7 @@ static void __init setup_unwind_table(struct unwind_table *table,
                 ptr = (const u8 *)(fde + 2);
                 header->table[n].start = read_pointer(&ptr,
                                                       (const u8 *)(fde + 1) + *fde,
-                                                      fde_pointer_type(cie));
+                                                      fde_pointer_type(cie), 0, 0);
                 header->table[n].fde = (unsigned long)fde;
                 ++n;
         }
@@ -486,7 +505,9 @@ static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *table)
 
 static unsigned long read_pointer(const u8 **pLoc,
                                   const void *end,
-                                  signed ptrType)
+                                  signed ptrType,
+                                  unsigned long text_base,
+                                  unsigned long data_base)
 {
         unsigned long value = 0;
         union {
@@ -498,13 +519,17 @@ static unsigned long read_pointer(const u8 **pLoc,
                 const unsigned long *pul;
         } ptr;
 
-        if (ptrType < 0 || ptrType == DW_EH_PE_omit)
+        if (ptrType < 0 || ptrType == DW_EH_PE_omit) {
+                dprintk(1, "Invalid pointer encoding %02X (%p,%p).", ptrType, *pLoc, end);
                 return 0;
+        }
         ptr.p8 = *pLoc;
         switch(ptrType & DW_EH_PE_FORM) {
         case DW_EH_PE_data2:
-                if (end < (const void *)(ptr.p16u + 1))
+                if (end < (const void *)(ptr.p16u + 1)) {
+                        dprintk(1, "Data16 overrun (%p,%p).", ptr.p8, end);
                         return 0;
+                }
                 if(ptrType & DW_EH_PE_signed)
                         value = get_unaligned(ptr.p16s++);
                 else
@@ -512,8 +537,10 @@ static unsigned long read_pointer(const u8 **pLoc,
                 break;
         case DW_EH_PE_data4:
 #ifdef CONFIG_64BIT
-                if (end < (const void *)(ptr.p32u + 1))
+                if (end < (const void *)(ptr.p32u + 1)) {
+                        dprintk(1, "Data32 overrun (%p,%p).", ptr.p8, end);
                         return 0;
+                }
                 if(ptrType & DW_EH_PE_signed)
                         value = get_unaligned(ptr.p32s++);
                 else
@@ -525,8 +552,10 @@ static unsigned long read_pointer(const u8 **pLoc,
                 BUILD_BUG_ON(sizeof(u32) != sizeof(value));
 #endif
         case DW_EH_PE_native:
-                if (end < (const void *)(ptr.pul + 1))
+                if (end < (const void *)(ptr.pul + 1)) {
+                        dprintk(1, "DataUL overrun (%p,%p).", ptr.p8, end);
                         return 0;
+                }
                 value = get_unaligned(ptr.pul++);
                 break;
         case DW_EH_PE_leb128:
@@ -534,10 +563,14 @@ static unsigned long read_pointer(const u8 **pLoc,
                 value = ptrType & DW_EH_PE_signed
                         ? get_sleb128(&ptr.p8, end)
                         : get_uleb128(&ptr.p8, end);
-                if ((const void *)ptr.p8 > end)
+                if ((const void *)ptr.p8 > end) {
+                        dprintk(1, "DataLEB overrun (%p,%p).", ptr.p8, end);
                         return 0;
+                }
                 break;
         default:
+                dprintk(2, "Cannot decode pointer type %02X (%p,%p).",
+                        ptrType, ptr.p8, end);
                 return 0;
         }
         switch(ptrType & DW_EH_PE_ADJUST) {
@@ -546,12 +579,33 @@ static unsigned long read_pointer(const u8 **pLoc,
         case DW_EH_PE_pcrel:
                 value += (unsigned long)*pLoc;
                 break;
+        case DW_EH_PE_textrel:
+                if (likely(text_base)) {
+                        value += text_base;
+                        break;
+                }
+                dprintk(2, "Text-relative encoding %02X (%p,%p), but zero text base.",
+                        ptrType, *pLoc, end);
+                return 0;
+        case DW_EH_PE_datarel:
+                if (likely(data_base)) {
+                        value += data_base;
+                        break;
+                }
+                dprintk(2, "Data-relative encoding %02X (%p,%p), but zero data base.",
+                        ptrType, *pLoc, end);
+                return 0;
         default:
+                dprintk(2, "Cannot adjust pointer type %02X (%p,%p).",
+                        ptrType, *pLoc, end);
                 return 0;
         }
         if ((ptrType & DW_EH_PE_indirect)
-            && __get_user(value, (unsigned long *)value))
+            && probe_kernel_address((unsigned long *)value, value)) {
+                dprintk(1, "Cannot read indirect value %lx (%p,%p).",
+                        value, *pLoc, end);
                 return 0;
+        }
         *pLoc = ptr.p8;
 
         return value;
@@ -594,7 +648,8 @@ static signed fde_pointer_type(const u32 *cie)
                         case 'P': {
                                         signed ptrType = *ptr++;
 
-                                        if (!read_pointer(&ptr, end, ptrType) || ptr > end)
+                                        if (!read_pointer(&ptr, end, ptrType, 0, 0)
+                                            || ptr > end)
                                                 return -1;
                                 }
                                 break;
@@ -654,7 +709,8 @@ static int processCFI(const u8 *start,
                         case DW_CFA_nop:
                                 break;
                         case DW_CFA_set_loc:
-                                if ((state->loc = read_pointer(&ptr.p8, end, ptrType)) == 0)
+                                state->loc = read_pointer(&ptr.p8, end, ptrType, 0, 0);
+                                if (state->loc == 0)
                                         result = 0;
                                 break;
                         case DW_CFA_advance_loc1:
@@ -700,8 +756,10 @@ static int processCFI(const u8 *start,
                                         state->label = NULL;
                                         return 1;
                                 }
-                                if (state->stackDepth >= MAX_STACK_DEPTH)
+                                if (state->stackDepth >= MAX_STACK_DEPTH) {
+                                        dprintk(1, "State stack overflow (%p,%p).", ptr.p8, end);
                                         return 0;
+                                }
                                 state->stack[state->stackDepth++] = ptr.p8;
                                 break;
                         case DW_CFA_restore_state:
@@ -716,8 +774,10 @@ static int processCFI(const u8 *start,
                                         result = processCFI(start, end, 0, ptrType, state);
                                         state->loc = loc;
                                         state->label = label;
-                                } else
+                                } else {
+                                        dprintk(1, "State stack underflow (%p,%p).", ptr.p8, end);
                                         return 0;
+                                }
                                 break;
                         case DW_CFA_def_cfa:
                                 state->cfa.reg = get_uleb128(&ptr.p8, end);
@@ -749,6 +809,7 @@ static int processCFI(const u8 *start,
                                 break;
                         case DW_CFA_GNU_window_save:
                         default:
+                                dprintk(1, "Unrecognized CFI op %02X (%p,%p).", ptr.p8[-1], ptr.p8 - 1, end);
                                 result = 0;
                                 break;
                         }
@@ -764,12 +825,17 @@ static int processCFI(const u8 *start,
                         set_rule(*ptr.p8++ & 0x3f, Nowhere, 0, state);
                         break;
                 }
-                if (ptr.p8 > end)
+                if (ptr.p8 > end) {
+                        dprintk(1, "Data overrun (%p,%p).", ptr.p8, end);
                         result = 0;
+                }
                 if (result && targetLoc != 0 && targetLoc < state->loc)
                         return 1;
         }
 
+        if (result && ptr.p8 < end)
+                dprintk(1, "Data underrun (%p,%p).", ptr.p8, end);
+
         return result
            && ptr.p8 == end
            && (targetLoc == 0
@@ -786,7 +852,7 @@ int unwind(struct unwind_frame_info *frame)
 #define FRAME_REG(r, t) (((t *)frame)[reg_info[r].offs])
         const u32 *fde = NULL, *cie = NULL;
         const u8 *ptr = NULL, *end = NULL;
-        unsigned long pc = UNW_PC(frame) - frame->call_frame;
+        unsigned long pc = UNW_PC(frame) - frame->call_frame, sp;
         unsigned long startLoc = 0, endLoc = 0, cfa;
         unsigned i;
         signed ptrType = -1;
@@ -813,9 +879,9 @@ int unwind(struct unwind_frame_info *frame)
                         ptr = hdr + 4;
                         end = hdr + table->hdrsz;
                         if (tableSize
-                            && read_pointer(&ptr, end, hdr[1])
+                            && read_pointer(&ptr, end, hdr[1], 0, 0)
                                == (unsigned long)table->address
-                            && (i = read_pointer(&ptr, end, hdr[2])) > 0
+                            && (i = read_pointer(&ptr, end, hdr[2], 0, 0)) > 0
                             && i == (end - ptr) / (2 * tableSize)
                             && !((end - ptr) % (2 * tableSize))) {
                                 do {
@@ -823,7 +889,8 @@ int unwind(struct unwind_frame_info *frame)
 
                                         startLoc = read_pointer(&cur,
                                                                 cur + tableSize,
-                                                                hdr[3]);
+                                                                hdr[3], 0,
+                                                                (unsigned long)hdr);
                                         if (pc < startLoc)
                                                 i /= 2;
                                         else {
@@ -834,13 +901,17 @@ int unwind(struct unwind_frame_info *frame)
                                 if (i == 1
                                     && (startLoc = read_pointer(&ptr,
                                                                 ptr + tableSize,
-                                                                hdr[3])) != 0
+                                                                hdr[3], 0,
+                                                                (unsigned long)hdr)) != 0
                                     && pc >= startLoc)
                                         fde = (void *)read_pointer(&ptr,
                                                                    ptr + tableSize,
-                                                                   hdr[3]);
+                                                                   hdr[3], 0,
+                                                                   (unsigned long)hdr);
                         }
                 }
+                if(hdr && !fde)
+                        dprintk(3, "Binary lookup for %lx failed.", pc);
 
                 if (fde != NULL) {
                         cie = cie_for_fde(fde, table);
@@ -851,17 +922,19 @@ int unwind(struct unwind_frame_info *frame)
                            && (ptrType = fde_pointer_type(cie)) >= 0
                            && read_pointer(&ptr,
                                            (const u8 *)(fde + 1) + *fde,
-                                           ptrType) == startLoc) {
+                                           ptrType, 0, 0) == startLoc) {
                                 if (!(ptrType & DW_EH_PE_indirect))
                                         ptrType &= DW_EH_PE_FORM|DW_EH_PE_signed;
                                 endLoc = startLoc
                                          + read_pointer(&ptr,
                                                         (const u8 *)(fde + 1) + *fde,
-                                                        ptrType);
+                                                        ptrType, 0, 0);
                                 if(pc >= endLoc)
                                         fde = NULL;
                         } else
                                 fde = NULL;
+                        if(!fde)
+                                dprintk(1, "Binary lookup result for %lx discarded.", pc);
                 }
                 if (fde == NULL) {
                         for (fde = table->address, tableSize = table->size;
@@ -881,7 +954,7 @@ int unwind(struct unwind_frame_info *frame)
                                 ptr = (const u8 *)(fde + 2);
                                 startLoc = read_pointer(&ptr,
                                                         (const u8 *)(fde + 1) + *fde,
-                                                        ptrType);
+                                                        ptrType, 0, 0);
                                 if (!startLoc)
                                         continue;
                                 if (!(ptrType & DW_EH_PE_indirect))
@@ -889,10 +962,12 @@ int unwind(struct unwind_frame_info *frame)
                                 endLoc = startLoc
                                          + read_pointer(&ptr,
                                                         (const u8 *)(fde + 1) + *fde,
-                                                        ptrType);
+                                                        ptrType, 0, 0);
                                 if (pc >= startLoc && pc < endLoc)
                                         break;
                         }
+                        if(!fde)
+                                dprintk(3, "Linear lookup for %lx failed.", pc);
                 }
         }
         if (cie != NULL) {
@@ -926,6 +1001,8 @@ int unwind(struct unwind_frame_info *frame)
                         if (ptr >= end || *ptr)
                                 cie = NULL;
                 }
+                if(!cie)
+                        dprintk(1, "CIE unusable (%p,%p).", ptr, end);
                 ++ptr;
         }
         if (cie != NULL) {
@@ -935,7 +1012,12 @@ int unwind(struct unwind_frame_info *frame)
                 state.dataAlign = get_sleb128(&ptr, end);
                 if (state.codeAlign == 0 || state.dataAlign == 0 || ptr >= end)
                         cie = NULL;
-                else {
+                else if (UNW_PC(frame) % state.codeAlign
+                         || UNW_SP(frame) % sleb128abs(state.dataAlign)) {
+                        dprintk(1, "Input pointer(s) misaligned (%lx,%lx).",
+                                UNW_PC(frame), UNW_SP(frame));
+                        return -EPERM;
+                } else {
                         retAddrReg = state.version <= 1 ? *ptr++ : get_uleb128(&ptr, end);
                         /* skip augmentation */
                         if (((const char *)(cie + 2))[1] == 'z') {
@@ -949,6 +1031,8 @@ int unwind(struct unwind_frame_info *frame)
                            || reg_info[retAddrReg].width != sizeof(unsigned long))
                                 cie = NULL;
                 }
+                if(!cie)
+                        dprintk(1, "CIE validation failed (%p,%p).", ptr, end);
         }
         if (cie != NULL) {
                 state.cieStart = ptr;
@@ -962,11 +1046,15 @@ int unwind(struct unwind_frame_info *frame)
                         if ((ptr += augSize) > end)
                                 fde = NULL;
                 }
+                if(!fde)
+                        dprintk(1, "FDE validation failed (%p,%p).", ptr, end);
         }
         if (cie == NULL || fde == NULL) {
 #ifdef CONFIG_FRAME_POINTER
                 unsigned long top, bottom;
 
+                if ((UNW_SP(frame) | UNW_FP(frame)) % sizeof(unsigned long))
+                        return -EPERM;
                 top = STACK_TOP(frame->task);
                 bottom = STACK_BOTTOM(frame->task);
 # if FRAME_RETADDR_OFFSET < 0
@@ -982,18 +1070,19 @@ int unwind(struct unwind_frame_info *frame)
                         & (sizeof(unsigned long) - 1))) {
                         unsigned long link;
 
-                        if (!__get_user(link,
+                        if (!probe_kernel_address(
                                         (unsigned long *)(UNW_FP(frame)
-                                                          + FRAME_LINK_OFFSET))
+                                                          + FRAME_LINK_OFFSET),
+                                                  link)
 # if FRAME_RETADDR_OFFSET < 0
                            && link > bottom && link < UNW_FP(frame)
 # else
                            && link > UNW_FP(frame) && link < bottom
 # endif
                            && !(link & (sizeof(link) - 1))
-                           && !__get_user(UNW_PC(frame),
+                           && !probe_kernel_address(
                                           (unsigned long *)(UNW_FP(frame)
-                                                            + FRAME_RETADDR_OFFSET))) {
+                                                            + FRAME_RETADDR_OFFSET), UNW_PC(frame))) {
                                 UNW_SP(frame) = UNW_FP(frame) + FRAME_RETADDR_OFFSET
 # if FRAME_RETADDR_OFFSET < 0
                                         -
@@ -1016,8 +1105,11 @@ int unwind(struct unwind_frame_info *frame)
            || state.regs[retAddrReg].where == Nowhere
            || state.cfa.reg >= ARRAY_SIZE(reg_info)
            || reg_info[state.cfa.reg].width != sizeof(unsigned long)
-           || state.cfa.offs % sizeof(unsigned long))
+           || FRAME_REG(state.cfa.reg, unsigned long) % sizeof(unsigned long)
+           || state.cfa.offs % sizeof(unsigned long)) {
+                dprintk(1, "Unusable unwind info (%p,%p).", ptr, end);
                 return -EIO;
+        }
         /* update frame */
 #ifndef CONFIG_AS_CFI_SIGNAL_FRAME
         if(frame->call_frame
@@ -1036,10 +1128,14 @@ int unwind(struct unwind_frame_info *frame)
 #else
 # define CASES CASE(8); CASE(16); CASE(32); CASE(64)
 #endif
+        pc = UNW_PC(frame);
+        sp = UNW_SP(frame);
         for (i = 0; i < ARRAY_SIZE(state.regs); ++i) {
                 if (REG_INVALID(i)) {
                         if (state.regs[i].where == Nowhere)
                                 continue;
+                        dprintk(1, "Cannot restore register %u (%d).",
+                                i, state.regs[i].where);
                         return -EIO;
                 }
                 switch(state.regs[i].where) {
@@ -1048,8 +1144,11 @@ int unwind(struct unwind_frame_info *frame)
                 case Register:
                         if (state.regs[i].value >= ARRAY_SIZE(reg_info)
                            || REG_INVALID(state.regs[i].value)
-                           || reg_info[i].width > reg_info[state.regs[i].value].width)
+                           || reg_info[i].width > reg_info[state.regs[i].value].width) {
+                                dprintk(1, "Cannot restore register %u from register %lu.",
+                                        i, state.regs[i].value);
                                 return -EIO;
+                        }
                         switch(reg_info[state.regs[i].value].width) {
 #define CASE(n) \
                         case sizeof(u##n): \
@@ -1059,6 +1158,9 @@ int unwind(struct unwind_frame_info *frame)
                         CASES;
 #undef CASE
                         default:
+                                dprintk(1, "Unsupported register size %u (%lu).",
+                                        reg_info[state.regs[i].value].width,
+                                        state.regs[i].value);
                                 return -EIO;
                         }
                         break;
@@ -1083,12 +1185,17 @@ int unwind(struct unwind_frame_info *frame)
                         CASES;
 #undef CASE
                         default:
+                                dprintk(1, "Unsupported register size %u (%u).",
+                                        reg_info[i].width, i);
                                 return -EIO;
                         }
                         break;
                 case Value:
-                        if (reg_info[i].width != sizeof(unsigned long))
+                        if (reg_info[i].width != sizeof(unsigned long)) {
+                                dprintk(1, "Unsupported value size %u (%u).",
+                                        reg_info[i].width, i);
                                 return -EIO;
+                        }
                         FRAME_REG(i, unsigned long) = cfa + state.regs[i].value
                                                             * state.dataAlign;
                         break;
@@ -1100,15 +1207,20 @@ int unwind(struct unwind_frame_info *frame)
                                     % sizeof(unsigned long)
                                     || addr < startLoc
                                     || addr + sizeof(unsigned long) < addr
-                                    || addr + sizeof(unsigned long) > endLoc)
+                                    || addr + sizeof(unsigned long) > endLoc) {
+                                        dprintk(1, "Bad memory location %lx (%lx).",
+                                                addr, state.regs[i].value);
                                         return -EIO;
+                                }
                                 switch(reg_info[i].width) {
 #define CASE(n)     case sizeof(u##n): \
-                                        __get_user(FRAME_REG(i, u##n), (u##n *)addr); \
+                                        probe_kernel_address((u##n *)addr, FRAME_REG(i, u##n)); \
                                         break
                                 CASES;
 #undef CASE
                                 default:
+                                        dprintk(1, "Unsupported memory size %u (%u).",
+                                                reg_info[i].width, i);
                                         return -EIO;
                                 }
                         }
@@ -1116,6 +1228,17 @@ int unwind(struct unwind_frame_info *frame)
                 }
         }
 
+        if (UNW_PC(frame) % state.codeAlign
+            || UNW_SP(frame) % sleb128abs(state.dataAlign)) {
+                dprintk(1, "Output pointer(s) misaligned (%lx,%lx).",
+                        UNW_PC(frame), UNW_SP(frame));
+                return -EIO;
+        }
+        if (pc == UNW_PC(frame) && sp == UNW_SP(frame)) {
+                dprintk(1, "No progress (%lx,%lx).", pc, sp);
+                return -EIO;
+        }
+
         return 0;
 #undef CASES
 #undef FRAME_REG