/* * netsniff-ng - the packet sniffing beast * Copyright 2012 Markus Amend , Deutsche Flugsicherung GmbH * Subject to the GPL, version 2. * * http://tools.ietf.org/html/rfc3032 */ #include #include #include /* for ntohs() */ #include #include "proto.h" #include "dissector_eth.h" #include "built_in.h" #include "pkt_buff.h" struct mpls_uchdr { uint32_t mpls_uc_hdr; } __packed; static int mpls_uc_next_proto(struct pkt_buff *pkt) { uint8_t proto; uint16_t key = 0; if (pkt_len(pkt)) proto = *(pkt->data); else return -EIO; /* FIXME: Right now only test for IP Version field */ switch (proto >> 4) { case 4: key = 0x0800; /* IPv4*/ break; case 6: key = 0x86DD; /* IPv6*/ break; default: /* Nothing detected ... */ return -ENOENT; } return key; } static void mpls_uc_full(struct pkt_buff *pkt) { int next; uint32_t mpls_uc_data; struct mpls_uchdr *mpls_uc; uint8_t s = 0; do { mpls_uc = (struct mpls_uchdr *) pkt_pull(pkt, sizeof(*mpls_uc)); if (mpls_uc == NULL) return; mpls_uc_data = ntohl(mpls_uc->mpls_uc_hdr); s = (mpls_uc_data >> 8) & 0x1; tprintf(" [ MPLS "); tprintf("Label (%u), ", mpls_uc_data >> 12); tprintf("Exp (%u), ", (mpls_uc_data >> 9) & 0x7); tprintf("S (%u), ", s); tprintf("TTL (%u)", (mpls_uc_data & 0xFF)); tprintf(" ]\n"); } while (!s); next = mpls_uc_next_proto(pkt); if (next < 0) return; pkt_set_proto(pkt, ð_lay2, (uint16_t) next); } static void mpls_uc_less(struct pkt_buff *pkt) { int next; uint32_t mpls_uc_data; struct mpls_uchdr *mpls_uc; uint8_t s = 0; do { mpls_uc = (struct mpls_uchdr *) pkt_pull(pkt, sizeof(*mpls_uc)); if (mpls_uc == NULL) return; mpls_uc_data = ntohl(mpls_uc->mpls_uc_hdr); s = (mpls_uc_data >> 8) & 0x1; tprintf(" MPLS/%u", mpls_uc_data >> 12); } while (!s); next = mpls_uc_next_proto(pkt); if (next < 0) return; pkt_set_proto(pkt, ð_lay2, (uint16_t) next); } struct protocol mpls_uc_ops = { .key = 0x8847, .print_full = mpls_uc_full, .print_less = mpls_uc_less, }; rivate-remove&id=321027c1fe77f892f4ea07846aeae08cefbbb290'>diff
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authorPeter Zijlstra <peterz@infradead.org>2017-01-11 21:09:50 +0100
committerIngo Molnar <mingo@kernel.org>2017-01-14 10:56:11 +0100
commit321027c1fe77f892f4ea07846aeae08cefbbb290 (patch)
treee90493b64144be2e6e9564dca1afe870d393765c
parent63cae12bce9861cec309798d34701cf3da20bc71 (diff)
perf/core: Fix concurrent sys_perf_event_open() vs. 'move_group' race
Di Shen reported a race between two concurrent sys_perf_event_open() calls where both try and move the same pre-existing software group into a hardware context. The problem is exactly that described in commit: f63a8daa5812 ("perf: Fix event->ctx locking") ... where, while we wait for a ctx->mutex acquisition, the event->ctx relation can have changed under us. That very same commit failed to recognise sys_perf_event_context() as an external access vector to the events and thereby didn't apply the established locking rules correctly. So while one sys_perf_event_open() call is stuck waiting on mutex_lock_double(), the other (which owns said locks) moves the group about. So by the time the former sys_perf_event_open() acquires the locks, the context we've acquired is stale (and possibly dead). Apply the established locking rules as per perf_event_ctx_lock_nested() to the mutex_lock_double() for the 'move_group' case. This obviously means we need to validate state after we acquire the locks. Reported-by: Di Shen (Keen Lab) Tested-by: John Dias <joaodias@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Min Chong <mchong@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Fixes: f63a8daa5812 ("perf: Fix event->ctx locking") Link: http://lkml.kernel.org/r/20170106131444.GZ3174@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat
-rw-r--r--kernel/events/core.c58
1 files changed, 54 insertions, 4 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c