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authorNeilBrown <neilb@suse.de>2021-02-26 04:22:29 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-26 20:41:05 +0300
commit3d2fc4c082448e9c05792f9b2a11c1d5db408b85 (patch)
treec5a868257f23c4819b85b10fd5e09f46f3b50b31 /arch
parentb3656d8227f4c45812c6b40815d8f4e446ed372a (diff)
downloadlinux-3d2fc4c082448e9c05792f9b2a11c1d5db408b85.tar.xz
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@noble1 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> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/mm/pat/memtype.c4
1 files 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;
}