/* * netsniff-ng - the packet sniffing beast * Copyright 2009, 2010 Daniel Borkmann. * Copyright 2014, 2015 Tobias Klauser * Subject to the GPL, version 2. */ #include #include #include #include #include #include #include #include #include #include "xmalloc.h" #include "die.h" #include "ring.h" #include "built_in.h" void setup_ring_layout_generic(struct ring *ring, size_t size, bool jumbo_support) { fmemset(&ring->layout, 0, sizeof(ring->layout)); ring->layout.tp_block_size = (jumbo_support ? RUNTIME_PAGE_SIZE << 4 : RUNTIME_PAGE_SIZE << 2); ring->layout.tp_frame_size = (jumbo_support ? TPACKET_ALIGNMENT << 12 : TPACKET_ALIGNMENT << 7); ring->layout.tp_block_nr = size / ring->layout.tp_block_size; ring->layout.tp_frame_nr = size / ring->layout.tp_frame_size; } void mmap_ring_generic(int sock, struct ring *ring) { ring->mm_space = mmap(NULL, ring->mm_len, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_LOCKED | MAP_POPULATE, sock, 0); if (ring->mm_space == MAP_FAILED) panic("Cannot mmap {TX,RX}_RING!\n"); } void alloc_ring_frames_generic(struct ring *ring, size_t num, size_t size) { size_t i, len = num * sizeof(*ring->frames); ring->frames = xmalloc_aligned(len, CO_CACHE_LINE_SIZE); fmemset(ring->frames, 0, len); for (i = 0; i < num; ++i) { ring->frames[i].iov_len = size; ring->frames[i].iov_base = ring->mm_space + (i * size); } } void bind_ring_generic(int sock, struct ring *ring, int ifindex, bool tx_only) { int ret; /* The {TX,RX}_RING registers itself to the networking stack with * dev_add_pack(), so we have one single RX_RING for all devs * otherwise you'll get the packet twice. */ fmemset(&ring->s_ll, 0, sizeof(ring->s_ll)); ring->s_ll.sll_family = AF_PACKET; ring->s_ll.sll_ifindex = ifindex; ring->s_ll.sll_protocol = tx_only ? 0 : htons(ETH_P_ALL); ret = bind(sock, (struct sockaddr *) &ring->s_ll, sizeof(ring->s_ll)); if (ret < 0) panic("Cannot bind {TX,RX}_RING!\n"); } 0319aaebfec09e0144dc3341'>diff
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authorDouglas Miller <dougmill@linux.vnet.ibm.com>2017-01-28 06:42:20 -0600
committerTejun Heo <tj@kernel.org>2017-01-28 07:49:42 -0500
commit966d2b04e070bc040319aaebfec09e0144dc3341 (patch)
tree4b96156e3d1dd4dfd6039b7c219c9dc4616da52d /tools/arch/arm/include
parent1b1bc42c1692e9b62756323c675a44cb1a1f9dbd (diff)
percpu-refcount: fix reference leak during percpu-atomic transition
percpu_ref_tryget() and percpu_ref_tryget_live() should return "true" IFF they acquire a reference. But the return value from atomic_long_inc_not_zero() is a long and may have high bits set, e.g. PERCPU_COUNT_BIAS, and the return value of the tryget routines is bool so the reference may actually be acquired but the routines return "false" which results in a reference leak since the caller assumes it does not need to do a corresponding percpu_ref_put(). This was seen when performing CPU hotplug during I/O, as hangs in blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start) raced with percpu_ref_tryget (blk_mq_timeout_work). Sample stack trace: __switch_to+0x2c0/0x450 __schedule+0x2f8/0x970 schedule+0x48/0xc0 blk_mq_freeze_queue_wait+0x94/0x120 blk_mq_queue_reinit_work+0xb8/0x180 blk_mq_queue_reinit_prepare+0x84/0xa0 cpuhp_invoke_callback+0x17c/0x600 cpuhp_up_callbacks+0x58/0x150 _cpu_up+0xf0/0x1c0 do_cpu_up+0x120/0x150 cpu_subsys_online+0x64/0xe0 device_online+0xb4/0x120 online_store+0xb4/0xc0 dev_attr_store+0x68/0xa0 sysfs_kf_write+0x80/0xb0 kernfs_fop_write+0x17c/0x250 __vfs_write+0x6c/0x1e0 vfs_write+0xd0/0x270 SyS_write+0x6c/0x110 system_call+0x38/0xe0 Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS, and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests. However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0 and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set. The fix is to make the tryget routines use an actual boolean internally instead of the atomic long result truncated to a int. Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751 Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com> Reviewed-by: Jens Axboe <axboe@fb.com> Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints") Cc: stable@vger.kernel.org # v3.18+
Diffstat (limited to 'tools/arch/arm/include')