4f1b715c84
fasttrap hooks the userspace breakpoint handler; the hook looks up the breakpoint address in a hash table of tracepoints. It is possible for the tracepoint to be removed by a different thread in between the breakpoint trap and the hash table lookup, in which case SIGTRAP gets delivered to the target process. Fix the problem by adding a per-process generation counter that gets incremented when a tracepoint belonging to that process is removed. Then, when a lookup fails, the trapping instruction is restarted if the thread's counter doesn't match that of the process. Reviewed by: cem MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D19273
175 lines
5.7 KiB
C
175 lines
5.7 KiB
C
/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*
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* $FreeBSD$
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*
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*/
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#ifndef _DTRACE_CDDL_H_
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#define _DTRACE_CDDL_H_
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#include <sys/proc.h>
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#define LOCK_LEVEL 10
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/*
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* Kernel DTrace extension to 'struct proc' for FreeBSD.
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*/
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typedef struct kdtrace_proc {
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int p_dtrace_probes; /* Are there probes for this proc? */
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u_int64_t p_dtrace_count; /* Number of DTrace tracepoints */
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void *p_dtrace_helpers; /* DTrace helpers, if any */
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int p_dtrace_model;
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uint64_t p_fasttrap_tp_gen; /* Tracepoint hash table gen */
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} kdtrace_proc_t;
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/*
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* Kernel DTrace extension to 'struct thread' for FreeBSD.
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*/
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typedef struct kdtrace_thread {
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u_int8_t td_dtrace_stop; /* Indicates a DTrace-desired stop */
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u_int8_t td_dtrace_sig; /* Signal sent via DTrace's raise() */
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u_int8_t td_dtrace_inprobe; /* Are we in a probe? */
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u_int td_predcache; /* DTrace predicate cache */
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u_int64_t td_dtrace_vtime; /* DTrace virtual time */
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u_int64_t td_dtrace_start; /* DTrace slice start time */
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union __tdu {
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struct __tds {
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u_int8_t _td_dtrace_on;
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/* Hit a fasttrap tracepoint. */
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u_int8_t _td_dtrace_step;
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/* About to return to kernel. */
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u_int8_t _td_dtrace_ret;
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/* Handling a return probe. */
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u_int8_t _td_dtrace_ast;
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/* Saved ast flag. */
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#ifdef __amd64__
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u_int8_t _td_dtrace_reg;
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#endif
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} _tds;
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u_long _td_dtrace_ft; /* Bitwise or of these flags. */
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} _tdu;
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#define td_dtrace_ft _tdu._td_dtrace_ft
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#define td_dtrace_on _tdu._tds._td_dtrace_on
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#define td_dtrace_step _tdu._tds._td_dtrace_step
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#define td_dtrace_ret _tdu._tds._td_dtrace_ret
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#define td_dtrace_ast _tdu._tds._td_dtrace_ast
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#define td_dtrace_reg _tdu._tds._td_dtrace_reg
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uintptr_t td_dtrace_pc; /* DTrace saved pc from fasttrap. */
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uintptr_t td_dtrace_npc; /* DTrace next pc from fasttrap. */
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uintptr_t td_dtrace_scrpc;
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/* DTrace per-thread scratch location. */
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uintptr_t td_dtrace_astpc;
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/* DTrace return sequence location. */
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#ifdef __amd64__
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uintptr_t td_dtrace_regv;
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#endif
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u_int64_t td_hrtime; /* Last time on cpu. */
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void *td_dtrace_sscr; /* Saved scratch space location. */
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void *td_systrace_args; /* syscall probe arguments. */
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uint64_t td_fasttrap_tp_gen; /* Tracepoint hash table gen. */
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} kdtrace_thread_t;
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/*
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* Definitions to reference fields in the FreeBSD DTrace structures defined
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* above using the names of fields in similar structures in Solaris. Note
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* that the separation on FreeBSD is a licensing constraint designed to
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* keep the GENERIC kernel BSD licensed.
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*/
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#define t_dtrace_vtime td_dtrace->td_dtrace_vtime
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#define t_dtrace_start td_dtrace->td_dtrace_start
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#define t_dtrace_stop td_dtrace->td_dtrace_stop
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#define t_dtrace_sig td_dtrace->td_dtrace_sig
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#define t_dtrace_inprobe td_dtrace->td_dtrace_inprobe
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#define t_predcache td_dtrace->td_predcache
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#define t_dtrace_ft td_dtrace->td_dtrace_ft
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#define t_dtrace_on td_dtrace->td_dtrace_on
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#define t_dtrace_step td_dtrace->td_dtrace_step
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#define t_dtrace_ret td_dtrace->td_dtrace_ret
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#define t_dtrace_ast td_dtrace->td_dtrace_ast
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#define t_dtrace_reg td_dtrace->td_dtrace_reg
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#define t_dtrace_pc td_dtrace->td_dtrace_pc
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#define t_dtrace_npc td_dtrace->td_dtrace_npc
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#define t_dtrace_scrpc td_dtrace->td_dtrace_scrpc
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#define t_dtrace_astpc td_dtrace->td_dtrace_astpc
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#define t_dtrace_regv td_dtrace->td_dtrace_regv
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#define t_dtrace_sscr td_dtrace->td_dtrace_sscr
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#define t_dtrace_systrace_args td_dtrace->td_systrace_args
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#define t_fasttrap_tp_gen td_dtrace->td_fasttrap_tp_gen
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#define p_dtrace_helpers p_dtrace->p_dtrace_helpers
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#define p_dtrace_count p_dtrace->p_dtrace_count
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#define p_dtrace_probes p_dtrace->p_dtrace_probes
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#define p_model p_dtrace->p_dtrace_model
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#define p_fasttrap_tp_gen p_dtrace->p_fasttrap_tp_gen
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#define DATAMODEL_NATIVE 0
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#ifdef __amd64__
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#define DATAMODEL_LP64 0
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#define DATAMODEL_ILP32 1
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#else
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#define DATAMODEL_LP64 1
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#define DATAMODEL_ILP32 0
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#endif
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/*
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* Definitions for fields in struct proc which are named differently in FreeBSD.
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*/
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#define p_cred p_ucred
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#define p_parent p_pptr
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/*
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* Definitions for fields in struct thread which are named differently in FreeBSD.
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*/
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#define t_procp td_proc
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#define t_tid td_tid
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#define t_did td_tid
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#define t_cred td_ucred
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int priv_policy(const cred_t *, int, boolean_t, int, const char *);
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boolean_t priv_policy_only(const cred_t *, int, boolean_t);
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boolean_t priv_policy_choice(const cred_t *, int, boolean_t);
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/*
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* Test privilege. Audit success or failure, allow privilege debugging.
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* Returns 0 for success, err for failure.
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*/
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#define PRIV_POLICY(cred, priv, all, err, reason) \
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priv_policy((cred), (priv), (all), (err), (reason))
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/*
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* Test privilege. Audit success only, no privilege debugging.
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* Returns 1 for success, and 0 for failure.
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*/
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#define PRIV_POLICY_CHOICE(cred, priv, all) \
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priv_policy_choice((cred), (priv), (all))
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/*
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* Test privilege. No priv_debugging, no auditing.
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* Returns 1 for success, and 0 for failure.
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*/
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#define PRIV_POLICY_ONLY(cred, priv, all) \
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priv_policy_only((cred), (priv), (all))
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#endif /* !_DTRACE_CDDL_H_ */
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