linux/kernel/bpf/memalloc.c, branch v6.7

bpf: Add missed allocation hint for bpf_mem_cache_alloc_flags()

2023-11-27T02:00:26Z

bpf_mem_cache_alloc_flags() may call __alloc() directly when there is no free object in free list, but it doesn't initialize the allocation hint for the returned pointer. It may lead to bad memory dereference when freeing the pointer, so fix it by initializing the allocation hint. Fixes: 822fb26bdb55 ("bpf: Add a hint to allocated objects.") Signed-off-by: Hou Tao Acked-by: Yonghong Song Link: https://lore.kernel.org/r/20231111043821.2258513-1-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov

bpf: Add more WARN_ON_ONCE checks for mismatched alloc and free

2023-10-26T12:23:33Z

There are two possible mismatched alloc and free cases in BPF memory allocator: 1) allocate from cache X but free by cache Y with a different unit_size 2) allocate from per-cpu cache but free by kmalloc cache or vice versa So add more WARN_ON_ONCE checks in free_bulk() and __free_by_rcu() to spot these mismatched alloc and free early. Signed-off-by: Hou Tao Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20231021014959.3563841-1-houtao@huaweicloud.com

bpf: Use pcpu_alloc_size() in bpf_mem_free{_rcu}()

2023-10-20T21:15:13Z

For bpf_global_percpu_ma, the pointer passed to bpf_mem_free_rcu() is allocated by kmalloc() and its size is fixed (16-bytes on x86-64). So no matter which cache allocates the dynamic per-cpu area, on x86-64 cache[2] will always be used to free the per-cpu area. Fix the unbalance by checking whether the bpf memory allocator is per-cpu or not and use pcpu_alloc_size() instead of ksize() to find the correct cache for per-cpu free. Signed-off-by: Hou Tao Link: https://lore.kernel.org/r/20231020133202.4043247-5-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov

bpf: Re-enable unit_size checking for global per-cpu allocator

2023-10-20T21:15:13Z

With pcpu_alloc_size() in place, check whether or not the size of the dynamic per-cpu area is matched with unit_size. Signed-off-by: Hou Tao Link: https://lore.kernel.org/r/20231020133202.4043247-4-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2023-10-05T20:16:47Z

Cross-merge networking fixes after downstream PR. No conflicts (or adjacent changes of note). Signed-off-by: Jakub Kicinski

bpf: Use kmalloc_size_roundup() to adjust size_index

2023-09-30T16:39:28Z

Commit d52b59315bf5 ("bpf: Adjust size_index according to the value of KMALLOC_MIN_SIZE") uses KMALLOC_MIN_SIZE to adjust size_index, but as reported by Nathan, the adjustment is not enough, because __kmalloc_minalign() also decides the minimal alignment of slab object as shown in new_kmalloc_cache() and its value may be greater than KMALLOC_MIN_SIZE (e.g., 64 bytes vs 8 bytes under a riscv QEMU VM). Instead of invoking __kmalloc_minalign() in bpf subsystem to find the maximal alignment, just using kmalloc_size_roundup() directly to get the corresponding slab object size for each allocation size. If these two sizes are unmatched, adjust size_index to select a bpf_mem_cache with unit_size equal to the object_size of the underlying slab cache for the allocation size. Fixes: 822fb26bdb55 ("bpf: Add a hint to allocated objects.") Reported-by: Nathan Chancellor Closes: https://lore.kernel.org/bpf/20230914181407.GA1000274@dev-arch.thelio-3990X/ Signed-off-by: Hou Tao Tested-by: Emil Renner Berthing Link: https://lore.kernel.org/r/20230928101558.2594068-1-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2023-09-21T19:49:45Z

Cross-merge networking fixes after downstream PR. No conflicts. Signed-off-by: Paolo Abeni

bpf: Skip unit_size checking for global per-cpu allocator

2023-09-15T17:22:24Z

For global per-cpu allocator, the size of free object in free list doesn't match with unit_size and now there is no way to get the size of per-cpu pointer saved in free object, so just skip the checking. Reported-by: Stephen Rothwell Closes: https://lore.kernel.org/bpf/20230913133436.0eeec4cb@canb.auug.org.au/ Signed-off-by: Hou Tao Tested-by: Biju Das Link: https://lore.kernel.org/r/20230913135943.3137292-1-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov

bpf: Ensure unit_size is matched with slab cache object size

2023-09-11T19:41:37Z

Add extra check in bpf_mem_alloc_init() to ensure the unit_size of bpf_mem_cache is matched with the object_size of underlying slab cache. If these two sizes are unmatched, print a warning once and return -EINVAL in bpf_mem_alloc_init(), so the mismatch can be found early and the potential issue can be prevented. Suggested-by: Alexei Starovoitov Signed-off-by: Hou Tao Link: https://lore.kernel.org/r/20230908133923.2675053-4-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov

bpf: Don't prefill for unused bpf_mem_cache

2023-09-11T19:41:37Z

When the unit_size of a bpf_mem_cache is unmatched with the object_size of the underlying slab cache, the bpf_mem_cache will not be used, and the allocation will be redirected to a bpf_mem_cache with a bigger unit_size instead, so there is no need to prefill for these unused bpf_mem_caches. Signed-off-by: Hou Tao Link: https://lore.kernel.org/r/20230908133923.2675053-3-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov