[PATCH v11 10/14] tracing, arm64: untag user pointers in seq_print_user_ip

From: andreyknvl@google.com (Andrey Konovalov)
Subject: [PATCH v11 10/14] tracing, arm64: untag user pointers in seq_print_user_ip
Date: Fri, 15 Mar 2019 20:51:34 +0100	[thread overview]
Message-ID: <355e7c0dadaa2bb79d22e0b7aac7e4efc1114d49.1552679409.git.andreyknvl@google.com> (raw)
Message-ID: <20190315195134.OWw6zol1QJ3VSMp2QcWWL7QhKATiHQ0mK2tPTNP21xE@z> (raw)
In-Reply-To: <cover.1552679409.git.andreyknvl@google.com>

This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

seq_print_user_ip() uses provided user pointers for vma lookups, which
can only by done with untagged pointers.

Untag user pointers in this function.

Signed-off-by: Andrey Konovalov <andreyknvl at google.com>
---
 kernel/trace/trace_output.c |  5 +++--
 p                           | 45 +++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 2 deletions(-)
 create mode 100644 p

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 54373d93e251..6376bee93c84 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -370,6 +370,7 @@ static int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
 {
 	struct file *file = NULL;
 	unsigned long vmstart = 0;
+	unsigned long untagged_ip = untagged_addr(ip);
 	int ret = 1;
 
 	if (s->full)
@@ -379,7 +380,7 @@ static int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
 		const struct vm_area_struct *vma;
 
 		down_read(&mm->mmap_sem);
-		vma = find_vma(mm, ip);
+		vma = find_vma(mm, untagged_ip);
 		if (vma) {
 			file = vma->vm_file;
 			vmstart = vma->vm_start;
@@ -388,7 +389,7 @@ static int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
 			ret = trace_seq_path(s, &file->f_path);
 			if (ret)
 				trace_seq_printf(s, "[+0x%lx]",
-						 ip - vmstart);
+						 untagged_ip - vmstart);
 		}
 		up_read(&mm->mmap_sem);
 	}
diff --git a/p b/p
new file mode 100644
index 000000000000..9d6fa5386e55
--- /dev/null
+++ b/p
@@ -0,0 +1,45 @@
+commit 1fa6fadf644859e8a6a8ecce258444b49be8c7ee
+Author: Andrey Konovalov <andreyknvl at google.com>
+Date:   Mon Mar 4 17:20:32 2019 +0100
+
+    kasan: fix coccinelle warnings in kasan_p*_table
+    
+    kasan_p4d_table, kasan_pmd_table and kasan_pud_table are declared as
+    returning bool, but return 0 instead of false, which produces a coccinelle
+    warning. Fix it.
+    
+    Fixes: 0207df4fa1a8 ("kernel/memremap, kasan: make ZONE_DEVICE with work with KASAN")
+    Reported-by: kbuild test robot <lkp at intel.com>
+    Signed-off-by: Andrey Konovalov <andreyknvl at google.com>
+
+diff --git a/mm/kasan/init.c b/mm/kasan/init.c
+index 45a1b5e38e1e..fcaa1ca03175 100644
+--- a/mm/kasan/init.c
++++ b/mm/kasan/init.c
+@@ -42,7 +42,7 @@ static inline bool kasan_p4d_table(pgd_t pgd)
+ #else
+ static inline bool kasan_p4d_table(pgd_t pgd)
+ {
+-	return 0;
++	return false;
+ }
+ #endif
+ #if CONFIG_PGTABLE_LEVELS > 3
+@@ -54,7 +54,7 @@ static inline bool kasan_pud_table(p4d_t p4d)
+ #else
+ static inline bool kasan_pud_table(p4d_t p4d)
+ {
+-	return 0;
++	return false;
+ }
+ #endif
+ #if CONFIG_PGTABLE_LEVELS > 2
+@@ -66,7 +66,7 @@ static inline bool kasan_pmd_table(pud_t pud)
+ #else
+ static inline bool kasan_pmd_table(pud_t pud)
+ {
+-	return 0;
++	return false;
+ }
+ #endif
+ pte_t kasan_early_shadow_pte[PTRS_PER_PTE] __page_aligned_bss;
-- 
2.21.0.360.g471c308f928-goog
