Re: [Valgrind-users] Debugging a GC with valgrind
8
#define RZ_SZB (128)
char *sp = /* stack pointer value */;
char vbits[RZ_SZB] = {0};
VALGRIND_GET_VBITS(sp-RZ_SZB, vbits, RZ_SZB);
VALGRIND_MAKE_MEM_DEFINED(sp-RZ_SZB, RZ_SZB);
/* ... scan the red zone here ... */
VALGRIND_SET_VBITS(sp-RZ_SZB, vbits, RZ_SZB);
8
I can try that, but really the problem isn't reading
uninitialised values.
My theory is gc is deleting reachable store: the actual bug is NOT
reading some thing it should not be :)
...
That would be nice but it is unclear. Consider: the only way**
a GC could cause
the problem of an over-write would be to delete a reachable object.
** unless there were some stupid bug in the GC, I did have one: chasing
pointers down with recursion .. blows the stack on a long enough list.
...
I understood that this GC is directly calling malloc/free for each
object
(so there is GC pool management).
Then valgrind memcheck is (supposed to be) able to detect that GC is
freeing
a piece of memory, which is then dereferenced.
You might need to increase the
list of freed objects but kept in a corner to detect such bugs
by using the option
--freelist-vol=
If GC is maintaining its own mempool, then valgrind mempool requests
needs to be used.
If the application is multi-threaded, it might also be a race condition.
You could try helgrind or drd.
Philippe
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[Valgrind-users] AIX 5.3 - Valgrind 3.3.1
There is not much in the Net about AIX-Valgrind but i have found posts from people who claim that 3.3.0/1 runs. The ./configure works Properly for me... but here i get stuck, the question is why is that, i have no clue what the -C stands for otherwise i could eventually replace it. [] make make all-am make -C ../VEX CC=gcc AR=ar pub/libvex_guest_offsets.h make: Not a recognized flag: C usage: make [-einqrst] [-k|-S] [-d[A|adg[1|2]mstv]] [-D variable] [-f makefile ] [-j [jobs]] [variable=value ...] [target ...] make: 1254-004 The error code from the last command is 2. Stop. make: 1254-004 The error code from the last command is 2. Stop. Thanks , Oliver Based on previous e-mail correspondence with you and/or an agreement reached with you, we consider ourselves authorized to contact you via unsecured e-mail. Warning: (a) E-mails can involve SUBSTANTIAL RISKS, e.g. lack of confidentiality, potential manipulation of contents and/or sender's address, incorrect recipient (misdirection), viruses etc. We assume no responsi-bility for any loss or damage resulting from the use of e-mails. We recommend in particular that you do NOT SEND ANY SENSITIVE INFORMATION, that you do not include details of the previous message in any reply, and that you enter e-mail address(es) manually every time you write an e-mail. (b) As a matter of principle, we do NOT accept any ORDERS, revocations of orders or authorizations, blocking of credit cards, etc., sent by e-mail Should such an e-mail nevertheless be received, we are not obliged to act on or respond to the e-mail. Please notify us immediately if you received this e-mail by mistake or if you do not wish to receive any further e-mail correspondence. If you have received this e-mail by mistake, please completely delete it (and any attachments) and do not forward it or inform any other person of its contents.-- Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d___ Valgrind-users mailing list Valgrind-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/valgrind-users
Re: [Valgrind-users] AIX 5.3 - Valgrind 3.3.1
I'am now using Gmake, i can compile the memchecker with the hack: http://unix.derkeiler.com/Newsgroups/comp.unix.aix/2004-11/0553.html unfortunately it will only make it compile and coredump if i start it. Has anybody a clue what my real issue is here? I have added the -lcrypt flag and also created a dummy file with the undefined symbols. I would assume that on a real load i will not work because the referenced library doesn't exist. Question here would be how do i handle this in AIX 5.3 when i don't have a static linked binary for crypt. Thanks for all the responses already. ld: 0711-317 ERROR: Undefined symbol: encrypted_pw_passlen ld: 0711-317 ERROR: Undefined symbol: max_history_size ld: 0711-317 ERROR: Undefined symbol: crypt_r ld: 0711-317 ERROR: Undefined symbol: getpass_auto ld: 0711-317 ERROR: Undefined symbol: max_pw_passlen Igmar Palsenberg ig...@palsenberg.com 1/21/2011 12:02 pm The ./configure works Properly for me... but here i get stuck, the question is why is that, i have no clue what the -C stands for otherwise i could eventually replace it. install GNU make. Don't even bother porting to the AIX make. Igmar Based on previous e-mail correspondence with you and/or an agreement reached with you, we consider ourselves authorized to contact you via unsecured e-mail. Warning: (a) E-mails can involve SUBSTANTIAL RISKS, e.g. lack of confidentiality, potential manipulation of contents and/or sender's address, incorrect recipient (misdirection), viruses etc. We assume no responsi-bility for any loss or damage resulting from the use of e-mails. We recommend in particular that you do NOT SEND ANY SENSITIVE INFORMATION, that you do not include details of the previous message in any reply, and that you enter e-mail address(es) manually every time you write an e-mail. (b) As a matter of principle, we do NOT accept any ORDERS, revocations of orders or authorizations, blocking of credit cards, etc., sent by e-mail Should such an e-mail nevertheless be received, we are not obliged to act on or respond to the e-mail. Please notify us immediately if you received this e-mail by mistake or if you do not wish to receive any further e-mail correspondence. If you have received this e-mail by mistake, please completely delete it (and any attachments) and do not forward it or inform any other person of its contents.-- Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d___ Valgrind-users mailing list Valgrind-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/valgrind-users
Re: [Valgrind-users] AIX 5.3 - Valgrind 3.3.1
On 2011-01-21 08:59, Stutz Oliver wrote: There is not much in the Net about AIX-Valgrind but i have found posts from people who claim that 3.3.0/1 runs. The ./configure works Properly for me... but here i get stuck, the question is why is that, i have no clue what the -C stands for otherwise i could eventually replace it. [] make make all-am make -C ../VEX CC=gcc AR=ar pub/libvex_guest_offsets.h make: Not a recognized flag: C usage: make [-einqrst] [-k|-S] [-d[A|adg[1|2]mstv]] [-D variable] [-f makefile ] [-j [jobs]] [variable=value ...] [target ...] make: 1254-004 The error code from the last command is 2. Stop. make: 1254-004 The error code from the last command is 2. Stop. Thanks , Oliver You're using some (or the) AIX make command. Try writing a small wrapper script that passes any and all parameters on to an installed GNU make and manipulate the PATH before invoking the build, to make sure your script is found under the name make before any other binary/script. -C in GNU make changes into the directory given as parameter to the switch. // Oliver signature.asc Description: OpenPGP digital signature -- Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d___ Valgrind-users mailing list Valgrind-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/valgrind-users
[Valgrind-users] Fwd: Re: AIX 5.3 - Valgrind 3.3.1
I have now added the -lcrypt flag and it actually can resolve the symbols found in libc.a The Problem is that Valgrind Coredumps immediately after start with sig 4 Has nobody a Static Linked Valgrind for AIX 5.3? We also used OBJECT_MODE=64 and the other time with 32 The 64 bit version will stop at compile time with some assembler problem llong and the 32 bit version finished but coredumps on execution Thanks, Oliver _ I'am now using Gmake, i can compile the memchecker with the hack: http://unix.derkeiler.com/Newsgroups/comp.unix.aix/2004-11/0553.html unfortunately it will only make it compile and coredump if i start it. Has anybody a clue what my real issue is here? I have added the -lcrypt flag and also created a dummy file with the undefined symbols. I would assume that on a real load i will not work because the referenced library doesn't exist. Question here would be how do i handle this in AIX 5.3 when i don't have a static linked binary for crypt. Thanks for all the responses already. ld: 0711-317 ERROR: Undefined symbol: encrypted_pw_passlen ld: 0711-317 ERROR: Undefined symbol: max_history_size ld: 0711-317 ERROR: Undefined symbol: crypt_r ld: 0711-317 ERROR: Undefined symbol: getpass_auto ld: 0711-317 ERROR: Undefined symbol: max_pw_passlen Igmar Palsenberg ig...@palsenberg.com 1/21/2011 12:02 pm The ./configure works Properly for me... but here i get stuck, the question is why is that, i have no clue what the -C stands for otherwise i could eventually replace it. install GNU make. Don't even bother porting to the AIX make. Igmar Based on previous e-mail correspondence with you and/or an agreement reached with you, we consider ourselves authorized to contact you via unsecured e-mail. Warning: (a) E-mails can involve SUBSTANTIAL RISKS, e.g. lack of confidentiality, potential manipulation of contents and/or sender's address, incorrect recipient (misdirection), viruses etc. We assume no responsi-bility for any loss or damage resulting from the use of e-mails. We recommend in particular that you do NOT SEND ANY SENSITIVE INFORMATION, that you do not include details of the previous message in any reply, and that you enter e-mail address(es) manually every time you write an e-mail. (b) As a matter of principle, we do NOT accept any ORDERS, revocations of orders or authorizations, blocking of credit cards, etc., sent by e-mail Should such an e-mail nevertheless be received, we are not obliged to act on or respond to the e-mail. Please notify us immediately if you received this e-mail by mistake or if you do not wish to receive any further e-mail correspondence. If you have received this e-mail by mistake, please completely delete it (and any attachments) and do not forward it or inform any other person of its contents.-- Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d___ Valgrind-users mailing list Valgrind-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/valgrind-users
Re: [Valgrind-users] AIX 5.3 - Valgrind 3.3.1
IIRC, you need to be running a 64-bit kernel. V will segfault on AIX if you're running a 32-bit kernel. Also I thought 3.4.1 worked on AIX5.3. It's generally better than 3.3.1, if only because then you'll have origin tracking for Memcheck. J On Friday, January 21, 2011, Stutz Oliver wrote: There is not much in the Net about AIX-Valgrind but i have found posts from people who claim that 3.3.0/1 runs. The ./configure works Properly for me... but here i get stuck, the question is why is that, i have no clue what the -C stands for otherwise i could eventually replace it. [] make make all-am make -C ../VEX CC=gcc AR=ar pub/libvex_guest_offsets.h make: Not a recognized flag: C usage: make [-einqrst] [-k|-S] [-d[A|adg[1|2]mstv]] [-D variable] [-f makefile ] [-j [jobs]] [variable=value ...] [target ...] make: 1254-004 The error code from the last command is 2. Stop. make: 1254-004 The error code from the last command is 2. Stop. Thanks , Oliver Based on previous e-mail correspondence with you and/or an agreement reached with you, we consider ourselves authorized to contact you via unsecured e-mail. Warning: (a) E-mails can involve SUBSTANTIAL RISKS, e.g. lack of confidentiality, potential manipulation of contents and/or sender's address, incorrect recipient (misdirection), viruses etc. We assume no responsi-bility for any loss or damage resulting from the use of e-mails. We recommend in particular that you do NOT SEND ANY SENSITIVE INFORMATION, that you do not include details of the previous message in any reply, and that you enter e-mail address(es) manually every time you write an e-mail. (b) As a matter of principle, we do NOT accept any ORDERS, revocations of orders or authorizations, blocking of credit cards, etc., sent by e-mail Should such an e-mail nevertheless be received, we are not obliged to act on or respond to the e-mail. Please notify us immediately if you received this e-mail by mistake or if you do not wish to receive any further e-mail correspondence. If you have received this e-mail by mistake, please completely delete it (and any attachments) and do not forward it or inform any other person of its contents. -- Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d ___ Valgrind-users mailing list Valgrind-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/valgrind-users
Re: [Valgrind-users] Debugging a GC with valgrind
On Jan 20, 2011, at 6:43 PM CST, john skaller wrote: OK, so I do this now: ... if(debug) fprintf(stderr, Check if *%p=%p is a pointer\n,i,*(void**)i); scan_object(*(void**)i, reclimit); ... The VALGRIND macro there doesn't seem to be working, I must be doing something wrong. I'm trying to just mark the whole stack as defined. Here's output: ... The way that I read this output is that your range variable and the data in that range is probably defined because Valgrind isn't flagging i or the value at address i when you perform the Check if fprintf above. Rather, it's flagging an fprintf inside of scan_object on line 451, whose output you did not include. Maybe it's the reclimit variable? ==7159== Uninitialised value was created by a stack allocation ==7159==at 0x1E492: flx::gc::collector::flx_collector_t::mark(std::vectorflx::pthread::memory_range_t, std::allocatorflx::pthread::memory_range_t *) (flx_collector.cpp:337) It's odd that the stack allocation is attributed to line 337, which AFAICT is the line where scan_object is called. Is there some sort of odd automatic C++ temporary allocation happening here that I can't see because some other code isn't shown here or (more likely) my C++ is too rusty somehow? Perhaps under optimization an uninitialized and otherwise-unused reclimit variable only gets created at the time that the arguments to scan_object are pushed onto the stack? -Dave -- Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d ___ Valgrind-users mailing list Valgrind-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/valgrind-users
Re: [Valgrind-users] Debugging a GC with valgrind
On 22/01/2011, at 2:30 AM, Dave Goodell wrote:
On Jan 20, 2011, at 6:43 PM CST, john skaller wrote:
OK, so I do this now:
...
if(debug)
fprintf(stderr, Check if *%p=%p is a pointer\n,i,*(void**)i);
scan_object(*(void**)i, reclimit);
...
The VALGRIND macro there doesn't seem to be working, I must be
doing something wrong. I'm trying to just mark the whole stack as defined.
Here's output:
...
The way that I read this output is that your range variable and the data in
that range is probably defined because Valgrind isn't flagging i or the value
at address i when you perform the Check if fprintf above.
Good point..
Rather, it's flagging an fprintf inside of scan_object on line 451, whose
output you did not include. Maybe it's the reclimit variable?
I shouldn't think so, though it's hard to be sure of anything.
Scan object look to see if the pointer value it gets is actually a pointer
into the heap.
If so, it looks at the pointer inside the pointed at object (recursively). I
know where the
pointers are because I know the type of every heap object.
It doesn't chase down the pointer unless its an actual pointer into the heap:
it doesn't chase ints, raw C pointers (not Felix heap allocated), or pointers
into the stack or static storage.
In this program there is only ONE data structure on the heap: list nodes.
Which contain exactly one pointer (to the next node). There are no list
nodes on the stack.
The pointers used for lists are actually tagged pointers:
struct _uctor_ { int variant; void *data; };
variant = 0 means end of list and 1 means a node with data in it is being
pointed at.
[So a node the last node has a value in it and a pointer with variant 0 and
data=NULL].
It is the variant which is sometimes overwritten with a value like 99762976,
it should be only 0 or 1, my has switches on the variant, which include
a wildcard for values other than 0 or 1, which cause a diagnostic to be
printed match failure and then abort the program.
==7159== Uninitialised value was created by a stack allocation
==7159==at 0x1E492:
flx::gc::collector::flx_collector_t::mark(std::vectorflx::pthread::memory_range_t,
std::allocatorflx::pthread::memory_range_t *) (flx_collector.cpp:337)
It's odd that the stack allocation is attributed to line 337, which AFAICT is
the line where scan_object is called. Is there some sort of odd automatic
C++ temporary allocation happening here that I can't see because some other
code isn't shown here or (more likely) my C++ is too rusty somehow?
I don't think so.
Perhaps under optimization an uninitialized and otherwise-unused reclimit
variable only gets created at the time that the arguments to scan_object are
pushed onto the stack?
Well that's possible, but I'm doing a debug build, I *think* that doesn't do
C++ optimisation
(normally I run with -O3 on gcc).
The nasty thing is now it is working, some quirk has changed something.. :)
--
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skal...@users.sourceforge.net
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