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authorAlexei Starovoitov <ast@plumgrid.com>2015-08-28 15:56:22 -0700
committerDavid S. Miller <davem@davemloft.net>2015-08-28 16:27:27 -0700
commit1a6877b9c0c2ad901d4335d909432d3bb6d3a330 (patch)
tree25b3a1577a82199d1100834c1bbf6cefad34a5a7 /kernel
parentc9fd56b34efd06a031cbc918d288f09e38173ff9 (diff)
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lib: introduce strncpy_from_unsafe()
generalize FETCH_FUNC_NAME(memory, string) into strncpy_from_unsafe() and fix sparse warnings that were present in original implementation. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace_kprobe.c20
1 files changed, 4 insertions, 16 deletions
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index b7d0cdd9906c..c9956440d0e6 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -165,11 +165,9 @@ DEFINE_BASIC_FETCH_FUNCS(memory)
static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
void *addr, void *dest)
{
- long ret;
int maxlen = get_rloc_len(*(u32 *)dest);
u8 *dst = get_rloc_data(dest);
- u8 *src = addr;
- mm_segment_t old_fs = get_fs();
+ long ret;
if (!maxlen)
return;
@@ -178,23 +176,13 @@ static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
* Try to get string again, since the string can be changed while
* probing.
*/
- set_fs(KERNEL_DS);
- pagefault_disable();
-
- do
- ret = __copy_from_user_inatomic(dst++, src++, 1);
- while (dst[-1] && ret == 0 && src - (u8 *)addr < maxlen);
-
- dst[-1] = '\0';
- pagefault_enable();
- set_fs(old_fs);
+ ret = strncpy_from_unsafe(dst, addr, maxlen);
if (ret < 0) { /* Failed to fetch string */
- ((u8 *)get_rloc_data(dest))[0] = '\0';
+ dst[0] = '\0';
*(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
} else {
- *(u32 *)dest = make_data_rloc(src - (u8 *)addr,
- get_rloc_offs(*(u32 *)dest));
+ *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
}
}
NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string));