Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton:
 "28 patches.

  Subsystems affected by this series: mm (memblock, pagealloc, hugetlb,
  highmem, kfence, oom-kill, madvise, kasan, userfaultfd, memcg, and
  zram), core-kernel, kconfig, fork, binfmt, MAINTAINERS, kbuild, and
  ia64"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (28 commits)
  zram: fix broken page writeback
  zram: fix return value on writeback_store
  mm/memcg: set memcg when splitting page
  mm/memcg: rename mem_cgroup_split_huge_fixup to split_page_memcg and add nr_pages argument
  ia64: fix ptrace(PTRACE_SYSCALL_INFO_EXIT) sign
  ia64: fix ia64_syscall_get_set_arguments() for break-based syscalls
  mm/userfaultfd: fix memory corruption due to writeprotect
  kasan: fix KASAN_STACK dependency for HW_TAGS
  kasan, mm: fix crash with HW_TAGS and DEBUG_PAGEALLOC
  mm/madvise: replace ptrace attach requirement for process_madvise
  include/linux/sched/mm.h: use rcu_dereference in in_vfork()
  kfence: fix reports if constant function prefixes exist
  kfence, slab: fix cache_alloc_debugcheck_after() for bulk allocations
  kfence: fix printk format for ptrdiff_t
  linux/compiler-clang.h: define HAVE_BUILTIN_BSWAP*
  MAINTAINERS: exclude uapi directories in API/ABI section
  binfmt_misc: fix possible deadlock in bm_register_write
  mm/highmem.c: fix zero_user_segments() with start > end
  hugetlb: do early cow when page pinned on src mm
  mm: use is_cow_mapping() across tree where proper
  ...

2 files changed, 19 insertions, 7 deletions

diff --git a/arch/ia64/include/asm/syscall.h b/arch/ia64/include/asm/syscall.h
index 6c6f16e409a8..0d23c0049301 100644
--- a/arch/ia64/include/asm/syscall.h
+++ b/arch/ia64/include/asm/syscall.h
@@ -32,7 +32,7 @@ static inline void syscall_rollback(struct task_struct *task,
 static inline long syscall_get_error(struct task_struct *task,
 				     struct pt_regs *regs)
 {
-	return regs->r10 == -1 ? regs->r8:0;
+	return regs->r10 == -1 ? -regs->r8:0;
 }
 
 static inline long syscall_get_return_value(struct task_struct *task,
diff --git a/arch/ia64/kernel/ptrace.c b/arch/ia64/kernel/ptrace.c
index c3490ee2daa5..e14f5653393a 100644
--- a/arch/ia64/kernel/ptrace.c
+++ b/arch/ia64/kernel/ptrace.c
@@ -2013,27 +2013,39 @@ static void syscall_get_set_args_cb(struct unw_frame_info *info, void *data)
 {
 	struct syscall_get_set_args *args = data;
 	struct pt_regs *pt = args->regs;
-	unsigned long *krbs, cfm, ndirty;
+	unsigned long *krbs, cfm, ndirty, nlocals, nouts;
 	int i, count;
 
 	if (unw_unwind_to_user(info) < 0)
 		return;
 
+	/*
+	 * We get here via a few paths:
+	 * - break instruction: cfm is shared with caller.
+	 *   syscall args are in out= regs, locals are non-empty.
+	 * - epsinstruction: cfm is set by br.call
+	 *   locals don't exist.
+	 *
+	 * For both cases argguments are reachable in cfm.sof - cfm.sol.
+	 * CFM: [ ... | sor: 17..14 | sol : 13..7 | sof : 6..0 ]
+	 */
 	cfm = pt->cr_ifs;
+	nlocals = (cfm >> 7) & 0x7f; /* aka sol */
+	nouts = (cfm & 0x7f) - nlocals; /* aka sof - sol */
 	krbs = (unsigned long *)info->task + IA64_RBS_OFFSET/8;
 	ndirty = ia64_rse_num_regs(krbs, krbs + (pt->loadrs >> 19));
 
 	count = 0;
 	if (in_syscall(pt))
-		count = min_t(int, args->n, cfm & 0x7f);
+		count = min_t(int, args->n, nouts);
 
+	/* Iterate over outs. */
 	for (i = 0; i < count; i++) {
+		int j = ndirty + nlocals + i + args->i;
 		if (args->rw)
-			*ia64_rse_skip_regs(krbs, ndirty + i + args->i) =
-				args->args[i];
+			*ia64_rse_skip_regs(krbs, j) = args->args[i];
 		else
-			args->args[i] = *ia64_rse_skip_regs(krbs,
-				ndirty + i + args->i);
+			args->args[i] = *ia64_rse_skip_regs(krbs, j);
 	}
 
 	if (!args->rw) {