-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 Am Fri, 27 Apr 2018 15:16:34 +0000 (UTC) Mateusz Guzik <m...@freebsd.org> schrieb:
> Author: mjg > Date: Fri Apr 27 15:16:34 2018 > New Revision: 333064 > URL: https://svnweb.freebsd.org/changeset/base/333064 > > Log: > systrace: track it like sdt probes > > While here predict false. > > Note the code is wrong (regardless of this change). Dereference of the > pointer can race with module unload. A fix would set the probe to a > nop stub instead of NULL. > > Modified: > head/sys/cddl/dev/systrace/systrace.c > head/sys/kern/kern_dtrace.c > head/sys/kern/subr_syscall.c > head/sys/sys/sysent.h > > Modified: head/sys/cddl/dev/systrace/systrace.c > ============================================================================== > --- head/sys/cddl/dev/systrace/systrace.c Fri Apr 27 13:59:24 2018 > (r333063) +++ head/sys/cddl/dev/systrace/systrace.c Fri Apr 27 15:16:34 > 2018 (r333064) @@ -135,6 +135,8 @@ extern const char > *freebsd32_syscallnames[]; > #error 1 << SYSTRACE_SHIFT must exceed number of system calls > #endif > > +static int systrace_enabled_count; > + > static void systrace_load(void *); > static void systrace_unload(void *); > > @@ -315,6 +317,9 @@ systrace_enable(void *arg, dtrace_id_t id, void *parg) > SYSENT[sysnum].sy_entry = id; > else > SYSENT[sysnum].sy_return = id; > + systrace_enabled_count++; > + if (systrace_enabled_count == 1) > + systrace_enabled = true; > } > > static void > @@ -324,6 +329,9 @@ systrace_disable(void *arg, dtrace_id_t id, void *parg > > SYSENT[sysnum].sy_entry = 0; > SYSENT[sysnum].sy_return = 0; > + systrace_enabled_count--; > + if (systrace_enabled_count == 0) > + systrace_enabled = false; > } > > static void > > Modified: head/sys/kern/kern_dtrace.c > ============================================================================== > --- head/sys/kern/kern_dtrace.c Fri Apr 27 13:59:24 2018 > (r333063) > +++ head/sys/kern/kern_dtrace.c Fri Apr 27 15:16:34 2018 > (r333064) > @@ -56,7 +56,8 @@ dtrace_doubletrap_func_t dtrace_doubletrap_func; > dtrace_pid_probe_ptr_t dtrace_pid_probe_ptr; > dtrace_return_probe_ptr_t dtrace_return_probe_ptr; > > -systrace_probe_func_t __read_frequently systrace_probe_func; > +bool __read_frequently systrace_enabled; > +systrace_probe_func_t systrace_probe_func; > > /* Return the DTrace process data size compiled in the kernel hooks. */ > size_t > > Modified: head/sys/kern/subr_syscall.c > ============================================================================== > --- head/sys/kern/subr_syscall.c Fri Apr 27 13:59:24 2018 > (r333063) > +++ head/sys/kern/subr_syscall.c Fri Apr 27 15:16:34 2018 > (r333064) > @@ -126,7 +126,8 @@ syscallenter(struct thread *td) > > #ifdef KDTRACE_HOOKS > /* Give the syscall:::entry DTrace probe a chance to fire. */ > - if (systrace_probe_func != NULL && sa->callp->sy_entry != 0) > + if (__predict_false(systrace_enabled && > + sa->callp->sy_entry != 0)) > (*systrace_probe_func)(sa, SYSTRACE_ENTRY, 0); > #endif > > @@ -140,7 +141,8 @@ syscallenter(struct thread *td) > > #ifdef KDTRACE_HOOKS > /* Give the syscall:::return DTrace probe a chance to fire. */ > - if (systrace_probe_func != NULL && sa->callp->sy_return != 0) > + if (__predict_false(systrace_enabled && > + sa->callp->sy_return != 0)) > (*systrace_probe_func)(sa, SYSTRACE_RETURN, > error ? -1 : td->td_retval[0]); > #endif > > Modified: head/sys/sys/sysent.h > ============================================================================== > --- head/sys/sys/sysent.h Fri Apr 27 13:59:24 2018 (r333063) > +++ head/sys/sys/sysent.h Fri Apr 27 15:16:34 2018 (r333064) > @@ -53,6 +53,7 @@ typedef void (*systrace_probe_func_t)(struct > syscall_a > enum systrace_probe_t, int); > typedef void (*systrace_args_func_t)(int, void *, uint64_t *, int *); > > +extern bool systrace_enabled; > extern systrace_probe_func_t systrace_probe_func; > > struct sysent { /* system call table */ > _______________________________________________ > svn-src-head@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/svn-src-head > To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org" Fail :-( [...] - --- kvm_proc.o --- In file included from /pool/sources/CURRENT/src/lib/libkvm/kvm_proc.c:66: /pool/sources/CURRENT/obj/pool/sources/CURRENT/src/amd64.amd64/tmp/usr/include/sys/sysent.h:56:8: error: unknown type name 'bool' extern bool systrace_enabled; ^ - -- O. Hartmann Ich widerspreche der Nutzung oder Übermittlung meiner Daten für Werbezwecke oder für die Markt- oder Meinungsforschung (§ 28 Abs. 4 BDSG). -----BEGIN PGP SIGNATURE----- iLUEARMKAB0WIQQZVZMzAtwC2T/86TrS528fyFhYlAUCWuNBKwAKCRDS528fyFhY lPfrAgCnR4AnAZrI+gsBQmmvVIdoSqHWGYPqs41ApeLTThmiWvUfMhsuA5izIpMf 1ZLKJ2riNAIntZIUsQcEINyRYxv0AgCn8qSQZvoTWoxujsgy6w4L6MGc9ZVnkcTj hG1ah5boD6MAT0SJYodK5hq8YQ3kXqVAdYBorqZafjoT093jOmVN =400x -----END PGP SIGNATURE----- _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
