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Subject[PATCH 2/3] x86: fix seq_file iteration for pat/memtype.c
The memtype seq_file iterator allocates a buffer in the ->start and
->next functions and frees it in the ->show function.
The preferred handling for such resources is to free them in the
subsequent ->next or ->stop function call.

Since Commit 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration
code and interface") there is no guarantee that ->show will be called
after ->next, so this function can now leak memory.

So move the freeing of the buffer to ->next and ->stop.

Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface")
Cc: Xin Long <lucien.xin@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
---
arch/x86/mm/pat/memtype.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/pat/memtype.c b/arch/x86/mm/pat/memtype.c
index 8f665c352bf0..ca311aaa67b8 100644
--- a/arch/x86/mm/pat/memtype.c
+++ b/arch/x86/mm/pat/memtype.c
@@ -1164,12 +1164,14 @@ static void *memtype_seq_start(struct seq_file *seq, loff_t *pos)

static void *memtype_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
+ kfree(v);
++*pos;
return memtype_get_idx(*pos);
}

static void memtype_seq_stop(struct seq_file *seq, void *v)
{
+ kfree(v);
}

static int memtype_seq_show(struct seq_file *seq, void *v)
@@ -1181,8 +1183,6 @@ static int memtype_seq_show(struct seq_file *seq, void *v)
entry_print->end,
cattr_name(entry_print->type));

- kfree(entry_print);
-
return 0;
}


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