diff options
| author |   Eric Dumazet <edumazet@google.com> | 2012-06-12 15:24:40 +0200 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2012-06-13 21:16:42 +0200 |
| commit | 047fe3605235888f3ebcda0c728cb31937eadfe6 (patch) | |
| tree | 9c33ef4b076bd54f686afe924cee01e21c55f427 /kernel/trace | |
| parent | blkcg: drop local variable @q from blkg_destroy() (diff) | |
| download | linux-dev-047fe3605235888f3ebcda0c728cb31937eadfe6.tar.xz linux-dev-047fe3605235888f3ebcda0c728cb31937eadfe6.zip | |
splice: fix racy pipe->buffers uses
Dave Jones reported a kernel BUG at mm/slub.c:3474! triggered
by splice_shrink_spd() called from vmsplice_to_pipe()
commit 35f3d14dbbc5 (pipe: add support for shrinking and growing pipes)
added capability to adjust pipe->buffers.
Problem is some paths don't hold pipe mutex and assume pipe->buffers
doesn't change for their duration.
Fix this by adding nr_pages_max field in struct splice_pipe_desc, and
use it in place of pipe->buffers where appropriate.
splice_shrink_spd() loses its struct pipe_inode_info argument.
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Tom Herbert <therbert@google.com>
Cc: stable <stable@vger.kernel.org> # 2.6.35
Tested-by: Dave Jones <davej@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/trace.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 68032c6177db..288488082224 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3609,6 +3609,7 @@ static ssize_t tracing_splice_read_pipe(struct file *filp, .pages = pages_def, .partial = partial_def, .nr_pages = 0, /* This gets updated below. */ + .nr_pages_max = PIPE_DEF_BUFFERS, .flags = flags, .ops = &tracing_pipe_buf_ops, .spd_release = tracing_spd_release_pipe, @@ -3680,7 +3681,7 @@ static ssize_t tracing_splice_read_pipe(struct file *filp, ret = splice_to_pipe(pipe, &spd); out: - splice_shrink_spd(pipe, &spd); + splice_shrink_spd(&spd); return ret; out_err: @@ -4231,6 +4232,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, struct splice_pipe_desc spd = { .pages = pages_def, .partial = partial_def, + .nr_pages_max = PIPE_DEF_BUFFERS, .flags = flags, .ops = &buffer_pipe_buf_ops, .spd_release = buffer_spd_release, @@ -4318,7 +4320,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, } ret = splice_to_pipe(pipe, &spd); - splice_shrink_spd(pipe, &spd); + splice_shrink_spd(&spd); out: return ret; } |