Date: Sat, 13 Aug 2016 23:56:32 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 211821] dtrace: invalid probe specifier lockstat:::: "/usr/lib/dtrace/tcp.d", line 201: operator / requires operands of arithmetic type Message-ID: <bug-211821-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=211821 Bug ID: 211821 Summary: dtrace: invalid probe specifier lockstat:::: "/usr/lib/dtrace/tcp.d", line 201: operator / requires operands of arithmetic type Product: Base System Version: 10.3-RELEASE Hardware: ppc OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: freebsd-bugs@FreeBSD.org Reporter: freebsd@g3os.org It seems that while dtrace knows about `hz, /usr/lib/dtrace/tcp.d does not, which causes the following problem: EXPECTED -------- When I run dtrace -ln [[[provider:]module:]probe:]name I expect output like this: # dtrace -ln lockstat::: ID PROVIDER MODULE FUNCTION NAME 25295 lockstat kernel mtx_lock_spin spin-acquire 25296 lockstat kernel mtx_lock_spin spin-spin 25297 lockstat kernel mtx_unlock_spin spin-release ... 25321 lockstat kernel sx_try_upgrade sx-upgrade 25322 lockstat kernel sx_downgrade sx-downgrade 25323 lockstat kernel thread_lock thread-spin ACTUAL ------ but instead I get output like this: dtrace -ln lockstat::: dtrace: invalid probe specifier lockstat:::: "/usr/lib/dtrace/tcp.d", line 201: operator / requires operands of arithmetic type # dtrace -l by itself is not affected. HACK/FIX -------- In /usr/lib/dtrace/tcp.d, when I change line 201 from: 201 tcps_rto = p == NULL ? -1 : (p->t_rxtcur * 1000) / `hz; to: 201 tcps_rto = p == NULL ? -1 : (p->t_rxtcur * 1000) / (int) `hz; I get the output I expect. My understanding is that backticks tell dtrace to use kernel variable names but I'm not sure how to include them so that dtrace sees it. I think hz is an int defined in sys/sys/kernel.h: 60 extern int tick; /* usec per tick (1000000 / hz) */ 61 extern int hz; /* system clock's frequency */ 62 extern int psratio; /* ratio: prof / stat */ and that t_rxtcur defined in sys/netinet/tcp_var.h is also an int. 202 203 int t_rxtcur; /* current retransmit value (ticks) */ 204 u_int t_maxseg; /* maximum segment size */ So I think casting to an int is reasonable. With my hack this also works: # dtrace -n 'BEGIN { trace(`hz); }' dtrace: description 'BEGIN ' matched 1 probe dtrace: buffer size lowered to 2m CPU ID FUNCTION:NAME 0 1 :BEGIN 1000 So I conclude that dtrace knows about hz but tcp.d does not. I suspect there is a way for tcp.d to know about kernel.h rather than do a cast, and that this would be preferable, but I don't know how to do that. SYSTEM INFO ----------- I'm using an eMac (PowerPC G4). # uname -a FreeBSD emac.local 10.3-RELEASE FreeBSD 10.3-RELEASE #0 r297264: Fri Mar 25 05:18:20 UTC 2016 root@releng1.nyi.freebsd.org:/usr/obj/powerpc.powerpc/usr/src/sys/GENERIC powerpc $ dmesg ... FreeBSD 10.3-RELEASE #0 r297264: Fri Mar 25 05:18:20 UTC 2016 root@releng1.nyi.freebsd.org:/usr/obj/powerpc.powerpc/usr/src/sys/GENERIC powerpc gcc version 4.2.1 20070831 patched [FreeBSD] cpu0: Motorola PowerPC 7455 revision 3.3, 1000.29 MHz cpu0: Features 9c000000<PPC32,ALTIVEC,FPU,MMU> cpu0: HID0 8450c0bc<EMCP,TBEN,NAP,DPM,ICE,DCE,SGE,BTIC,LRSTK,FOLD,BHT> real memory = 520597504 (496 MB) ... Thank you, - d -- You are receiving this mail because: You are the assignee for the bug.
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