From: Vasily Averin <vvs@xxxxxxxxxxxxx> [ Upstream commit 90435a7891a2259b0f74c5a1bc5600d0d64cba8f ] If seq_file .next fuction does not change position index, read after some lseek can generate an unexpected output. See also: https://bugzilla.kernel.org/show_bug.cgi?id=206283 v1 -> v2: removed missed increment in end of function Signed-off-by: Vasily Averin <vvs@xxxxxxxxxxxxx> Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Link: https://lore.kernel.org/bpf/eca84fdd-c374-a154-d874-6c7b55fc3bc4@xxxxxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- kernel/bpf/inode.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c index ecf42bec38c00..6f22e0e74ef24 100644 --- a/kernel/bpf/inode.c +++ b/kernel/bpf/inode.c @@ -196,6 +196,7 @@ static void *map_seq_next(struct seq_file *m, void *v, loff_t *pos) void *key = map_iter(m)->key; void *prev_key; + (*pos)++; if (map_iter(m)->done) return NULL; @@ -208,8 +209,6 @@ static void *map_seq_next(struct seq_file *m, void *v, loff_t *pos) map_iter(m)->done = true; return NULL; } - - ++(*pos); return key; } -- 2.20.1
