| Message ID | 20220131114600.21849-1-houtao1@huawei.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | [bpf-next] bpf: use VM_MAP instead of VM_ALLOC for ringbuf | expand |
On 1/31/22 12:46 PM, Hou Tao wrote: > Now the ringbuf area in /proc/vmallocinfo is showed as vmalloc, > but VM_ALLOC is only used for vmalloc(), and for the ringbuf area > it is created by mapping allocated pages, so use VM_MAP instead. > > After the change, ringbuf info in /proc/vmallocinfo will changed from: > [start]-[end] 24576 ringbuf_map_alloc+0x171/0x290 vmalloc user > to > [start]-[end] 24576 ringbuf_map_alloc+0x171/0x290 vmap user Could you elaborate in the commit msg if this also has some other internal effect aside from the /proc/vmallocinfo listing? Thanks! > Signed-off-by: Hou Tao <houtao1@huawei.com> > --- > kernel/bpf/ringbuf.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/bpf/ringbuf.c b/kernel/bpf/ringbuf.c > index 638d7fd7b375..710ba9de12ce 100644 > --- a/kernel/bpf/ringbuf.c > +++ b/kernel/bpf/ringbuf.c > @@ -104,7 +104,7 @@ static struct bpf_ringbuf *bpf_ringbuf_area_alloc(size_t data_sz, int numa_node) > } > > rb = vmap(pages, nr_meta_pages + 2 * nr_data_pages, > - VM_ALLOC | VM_USERMAP, PAGE_KERNEL); > + VM_MAP | VM_USERMAP, PAGE_KERNEL); > if (rb) { > kmemleak_not_leak(pages); > rb->pages = pages; >
Hi, On Tue, Feb 1, 2022 at 12:28 AM Daniel Borkmann <daniel@iogearbox.net> wrote: > > On 1/31/22 12:46 PM, Hou Tao wrote: > > Now the ringbuf area in /proc/vmallocinfo is showed as vmalloc, > > but VM_ALLOC is only used for vmalloc(), and for the ringbuf area > > it is created by mapping allocated pages, so use VM_MAP instead. > > > > After the change, ringbuf info in /proc/vmallocinfo will changed from: > > [start]-[end] 24576 ringbuf_map_alloc+0x171/0x290 vmalloc user > > to > > [start]-[end] 24576 ringbuf_map_alloc+0x171/0x290 vmap user > > Could you elaborate in the commit msg if this also has some other internal > effect aside from the /proc/vmallocinfo listing? Thanks! > For now, the VM_MAP flag only affects the output in /proc/vmallocinfo. Thanks, Tao > > Signed-off-by: Hou Tao <houtao1@huawei.com> > > --- > > kernel/bpf/ringbuf.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/kernel/bpf/ringbuf.c b/kernel/bpf/ringbuf.c > > index 638d7fd7b375..710ba9de12ce 100644 > > --- a/kernel/bpf/ringbuf.c > > +++ b/kernel/bpf/ringbuf.c > > @@ -104,7 +104,7 @@ static struct bpf_ringbuf *bpf_ringbuf_area_alloc(size_t data_sz, int numa_node) > > } > > > > rb = vmap(pages, nr_meta_pages + 2 * nr_data_pages, > > - VM_ALLOC | VM_USERMAP, PAGE_KERNEL); > > + VM_MAP | VM_USERMAP, PAGE_KERNEL); > > if (rb) { > > kmemleak_not_leak(pages); > > rb->pages = pages; > > >
Hi, On Tue, Feb 1, 2022 at 10:25 AM htbegin <hotforest@gmail.com> wrote: > > Hi, > > On Tue, Feb 1, 2022 at 12:28 AM Daniel Borkmann <daniel@iogearbox.net> wrote: > > > > On 1/31/22 12:46 PM, Hou Tao wrote: > > > Now the ringbuf area in /proc/vmallocinfo is showed as vmalloc, > > > but VM_ALLOC is only used for vmalloc(), and for the ringbuf area > > > it is created by mapping allocated pages, so use VM_MAP instead. > > > > > > After the change, ringbuf info in /proc/vmallocinfo will changed from: > > > [start]-[end] 24576 ringbuf_map_alloc+0x171/0x290 vmalloc user > > > to > > > [start]-[end] 24576 ringbuf_map_alloc+0x171/0x290 vmap user > > > > Could you elaborate in the commit msg if this also has some other internal > > effect aside from the /proc/vmallocinfo listing? Thanks! > > > For now, the VM_MAP flag only affects the output in /proc/vmallocinfo. Just find out that the VM_ALLOC will be used to check whether or not the mapped area needs to be marked as accessible by commit 2fd3fb0be1d1 ("kasan, vmalloc: unpoison VM_ALLOC pages after mapping"). And the patch can fix the vmalloc oob access reported by syzbot [1] , I will post v2 to illustrate that. Regards, Tao [1]: https://lore.kernel.org/bpf/0000000000000a9b7d05d6ee565f@google.com/T/#u > > Thanks, > Tao > > > Signed-off-by: Hou Tao <houtao1@huawei.com> > > > --- > > > kernel/bpf/ringbuf.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/kernel/bpf/ringbuf.c b/kernel/bpf/ringbuf.c > > > index 638d7fd7b375..710ba9de12ce 100644 > > > --- a/kernel/bpf/ringbuf.c > > > +++ b/kernel/bpf/ringbuf.c > > > @@ -104,7 +104,7 @@ static struct bpf_ringbuf *bpf_ringbuf_area_alloc(size_t data_sz, int numa_node) > > > } > > > > > > rb = vmap(pages, nr_meta_pages + 2 * nr_data_pages, > > > - VM_ALLOC | VM_USERMAP, PAGE_KERNEL); > > > + VM_MAP | VM_USERMAP, PAGE_KERNEL); > > > if (rb) { > > > kmemleak_not_leak(pages); > > > rb->pages = pages; > > > > >
diff --git a/kernel/bpf/ringbuf.c b/kernel/bpf/ringbuf.c index 638d7fd7b375..710ba9de12ce 100644 --- a/kernel/bpf/ringbuf.c +++ b/kernel/bpf/ringbuf.c @@ -104,7 +104,7 @@ static struct bpf_ringbuf *bpf_ringbuf_area_alloc(size_t data_sz, int numa_node) } rb = vmap(pages, nr_meta_pages + 2 * nr_data_pages, - VM_ALLOC | VM_USERMAP, PAGE_KERNEL); + VM_MAP | VM_USERMAP, PAGE_KERNEL); if (rb) { kmemleak_not_leak(pages); rb->pages = pages;
Now the ringbuf area in /proc/vmallocinfo is showed as vmalloc, but VM_ALLOC is only used for vmalloc(), and for the ringbuf area it is created by mapping allocated pages, so use VM_MAP instead. After the change, ringbuf info in /proc/vmallocinfo will changed from: [start]-[end] 24576 ringbuf_map_alloc+0x171/0x290 vmalloc user to [start]-[end] 24576 ringbuf_map_alloc+0x171/0x290 vmap user Signed-off-by: Hou Tao <houtao1@huawei.com> --- kernel/bpf/ringbuf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)