/* * netsniff-ng - the packet sniffing beast * Copyright 2009 - 2013 Daniel Borkmann. * Subject to the GPL, version 2. */ #include #include #include #include #include #include #include "pcap_io.h" #include "built_in.h" #include "xutils.h" #include "xio.h" #include "die.h" static ssize_t pcap_rw_write(int fd, pcap_pkthdr_t *phdr, enum pcap_type type, const uint8_t *packet, size_t len) { ssize_t ret, hdrsize = pcap_get_hdr_length(phdr, type), hdrlen = 0; ret = write_or_die(fd, &phdr->raw, hdrsize); if (unlikely(ret != hdrsize)) panic("Failed to write pkt header!\n"); hdrlen = pcap_get_length(phdr, type); if (unlikely(hdrlen != len)) return -EINVAL; ret = write_or_die(fd, packet, hdrlen); if (unlikely(ret != hdrlen)) panic("Failed to write pkt payload!\n"); return hdrsize + hdrlen; } static ssize_t pcap_rw_read(int fd, pcap_pkthdr_t *phdr, enum pcap_type type, uint8_t *packet, size_t len) { ssize_t ret, hdrsize = pcap_get_hdr_length(phdr, type), hdrlen = 0; ret = read_or_die(fd, &phdr->raw, hdrsize); if (unlikely(ret != hdrsize)) return -EIO; hdrlen = pcap_get_length(phdr, type); if (unlikely(hdrlen == 0 || hdrlen > len)) return -EINVAL; ret = read(fd, packet, hdrlen); if (unlikely(ret != hdrlen)) return -EIO; return hdrsize + hdrlen; } static void pcap_rw_init_once(void) { set_ioprio_rt(); } static void pcap_rw_fsync(int fd) { fdatasync(fd); } const struct pcap_file_ops pcap_rw_ops = { .init_once_pcap = pcap_rw_init_once, .pull_fhdr_pcap = pcap_generic_pull_fhdr, .push_fhdr_pcap = pcap_generic_push_fhdr, .read_pcap = pcap_rw_read, .write_pcap = pcap_rw_write, .fsync_pcap = pcap_rw_fsync, }; gtreecommitdiff
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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 /sound/pci/pcxhr
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 'sound/pci/pcxhr')