From: NeilBrown neilb@suse.de Subject: 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.
Link: https://lkml.kernel.org/r/161248539022.21478.13874455485854739066.stgit@nobl... Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface") Signed-off-by: NeilBrown neilb@suse.de Cc: Xin Long lucien.xin@gmail.com Cc: Alexander Viro viro@zeniv.linux.org.uk Cc: Andy Lutomirski luto@kernel.org Cc: Dave Hansen dave.hansen@linux.intel.com Cc: "David S. Miller" davem@davemloft.net Cc: Ingo Molnar mingo@redhat.com Cc: Jonathan Corbet corbet@lwn.net Cc: Marcelo Ricardo Leitner marcelo.leitner@gmail.com Cc: Neil Horman nhorman@tuxdriver.com Cc: Peter Zijlstra peterz@infradead.org Cc: Vlad Yasevich vyasevich@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
arch/x86/mm/pat/memtype.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/x86/mm/pat/memtype.c~x86-fix-seq_file-iteration-for-pat-memtypec +++ a/arch/x86/mm/pat/memtype.c @@ -1164,12 +1164,14 @@ static void *memtype_seq_start(struct se
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_f entry_print->end, cattr_name(entry_print->type));
- kfree(entry_print); - return 0; }
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