----- Original Message ----- > From: "Sanoj Unnikrishnan" <sunnikri@xxxxxxxxxx> > To: "Kinglong Mee" <kinglongmee@xxxxxxxxx> > Cc: "Gluster Devel" <gluster-devel@xxxxxxxxxxx> > Sent: Wednesday, June 28, 2017 5:18:56 PM > Subject: Re: glusterfsd crash when using quota without io-threads > > Hi Kinglong, > > I opened https://bugzilla.redhat.com/show_bug.cgi?id=1465861 to track this. > It seems to be an important issue that went undetected. > Thanks for catching this!! > > In my attempts to repro this , I found that on each run some random > structures where getting corrupted and running into segfault. > In order to assert that the stack was indeed growing into all the allocated > space and beyond, I set a guard page in the end of the allocated stack space > (so that we hit a segfault before overusing the space). > Below are the code changes. > > @@ -443,6 +443,8 @@ synctask_create (struct syncenv *env, size_t stacksize, > synctask_fn_t fn, > struct synctask *newtask = NULL; > xlator_t *this = THIS; > int destroymode = 0; > + int r=0; > + char *v; > > VALIDATE_OR_GOTO (env, err); > VALIDATE_OR_GOTO (fn, err); > @@ -498,9 +500,15 @@ synctask_create (struct syncenv *env, size_t stacksize, > synctask_fn_t fn, > gf_common_mt_syncstack); > newtask->ctx.uc_stack.ss_size = env->stacksize; > } else { > - newtask->stack = GF_CALLOC (1, stacksize, > + newtask->stack = GF_CALLOC (1, stacksize, > gf_common_mt_syncstack); > newtask->ctx.uc_stack.ss_size = stacksize; > + if (stacksize == 16*1024) { > + v = (unsigned long)((char *)(newtask->stack) + 4095) & (~4095); > + r = mprotect(v, 4096, PROT_NONE); > + gf_msg ("syncop", GF_LOG_ERROR, errno, > + LG_MSG_GETCONTEXT_FAILED, "SKU: using 16k stack starting at %p, mprotect > returned %d, guard page: %p", newtask->stack, r, v); > + } > } > > (gdb) where > #0 0x00007f8a92c51204 in _dl_lookup_symbol_x () from > /lib64/ld-linux-x86-64.so.2 > #1 0x00007f8a92c561e3 in _dl_fixup () from /lib64/ld-linux-x86-64.so.2 > #2 0x00007f8a92c5dd33 in _dl_runtime_resolve_avx () from > /lib64/ld-linux-x86-64.so.2 > #3 0x0000000000000000 in ?? () > > > (gdb) info reg > > rdi 0x7f8a92946188 140233141412232 > rbp 0x7f8a800b4000 0x7f8a800b4000 > rsp 0x7f8a800b4000 0x7f8a800b4000 > r8 0x7f8a92e4ba60 140233146677856 > > (gdb) layout asm > > >│0x7f8a92c51204 <_dl_lookup_symbol_x+4> push %r15 <== push on stack at the > >guarded page caused segfault > > From the brick log we have, > > [syncop.c:515:synctask_create] 0-syncop: SKU: using 16k stack starting at > 0x7f8a800b28f0, mprotect returned 0, guard page: 0x7f8a800b3000 [No data > available] > > Stack grows downward from 0x7f8a800b68f0 to 0x7f8a800b28f0 and the page > 0x7f8a800b3000 - 0x7f8a800b4000 is guarded , which is where the segfault hit > as seen in gdb. > > This confirms that the stack space is not sufficient and overflowing, > I am not sure why we don't hit this in the presence of IO threads though, Is it a case of too many frames in a single C stack? If that is the case, with io-threads in the graph STACK_WIND/UNWINDS won't result in the growth of a single C stack. In the past we've seen these kind of crashes (for eg., while updating sizes of all ancestors after a write by marker etc). > It > may just be that with io threads in graph, we may have some allocated and > unused memory which our stack freely grows into. It may just be a silent > undetected reuse of some memory. > > Regards, > Sanoj > > > > On Tue, Jun 13, 2017 at 10:49 AM, Sanoj Unnikrishnan < sunnikri@xxxxxxxxxx > > wrote: > > > > Hi Kinglong > I was reading about makecontext/swapcontext as well, > I did find an article that suggested to use mprotect and force a segfault to > check if we have a stack space issue here. > here is the link. http://www.evanjones.ca/software/threading.html . > > I don't think i can try this until tomorrow. > thanks and regards, > Sanoj > > On Tue, Jun 13, 2017 at 5:58 AM, Kinglong Mee < kinglongmee@xxxxxxxxx > > wrote: > > > Hi Sanoj, > > What's your opinion about this problem? > > thanks, > Kinglong Mee > > On 6/9/2017 17:20, Kinglong Mee wrote: > > Hi Sanoj, > > > > On 6/9/2017 15:48, Sanoj Unnikrishnan wrote: > >> I have not used valgrind before, so I may be wrong here. > >> > >> I think the valgrind_stack_deregister should have been after > >> GF_FREE_STACK. > >> That may explain the instance of invalid_write during stack_destroy calls > >> in after.log. > > > > No. I move it, but the instance of invalid_write also exist. > > > >> > >> There seems to be numerous issues reported in before.log (I am assuming, > >> you did not have the valgrind_stack_register call in it), > > > > Yes, the before.log is test without any code change(but without > > io-threads). > > > >> From http://valgrind.org/docs/manual/manual-core.html < > >> http://valgrind.org/docs/manual/manual-core.html >, looks like valgrind > >> detects client switching stack only If a memory of > 2MB change in Stack > >> pointer register. > > > > I test with a larger max-stackframe as, > > valgrind --leak-check=full --max-stackframe=242293216 > > > >> Is it possible that since marker is only using 16k, the stack pointer > >> could have been in less than 2MB offset from current Stack Pointer? > > > > Maybe. > > But with io-threads (with adding valgrind_stack_deregister), the valgrind > > only show some > > "Invalid read/write" about __gf_mem_invalidate. > > The only reason here I think is the stack size (16K) of marker using. > > > > I have not used makecontext/swapcontext before, am i right? > > 1. without swapconext, the stack maybe (just an example) > > --> io_stats-> quota-> marker-> io-threads ->..... > > > > 2. with swapcontext, > > --> io_stats-> quota-> marker > > swithto new stack -> io-threads > > > > After switchto new stack, the new stack size is 16K, > > Does it enough without io-threads? > > > > I don't know what's the behave of io-threads, does it call all sub-xlator > > using the 16K ? or others? > > > >> It seems unlikely to me since we are allocating the stack from heap. > >> > >> Did you try a run with the valgrind instrumentation, without changing > >> stack size ? > > > > OK. > > The following valgrind-without-stack-change.log is test with adding > > valgrind_stack_deregister > > (and without io-threads). > > > > thanks, > > Kinglong Mee > > > >> None of this explains the crash though.. We had seen a memory overrun > >> crash in same code path on netbsd earlier but did not follow up then. > >> Will look further into it. > >> > >> > >> > >> On Thu, Jun 8, 2017 at 4:51 PM, Kinglong Mee < kinglongmee@xxxxxxxxx > >> <mailto: kinglongmee@xxxxxxxxx >> wrote: > >> > >> Maybe it's my fault, I found valgrind can't parse context > >> switch(makecontext/swapcontext) by default. > >> So, I test with the following patch (tells valgrind new stack by > >> VALGRIND_STACK_DEREGISTER). > >> With it, only some "Invalid read/write" by __gf_mem_invalidate, Does it > >> right ?? > >> So, there is only one problem, if without io-threads, the stack size is > >> small for marker. > >> Am I right? > >> > >> Ps: > >> valgrind-before.log is the log without the following patch, the > >> valgrind-after.log is with the patch. > >> > >> ==35656== Invalid write of size 8 > >> ==35656== at 0x4E8FFD4: __gf_mem_invalidate (mem-pool.c:278) > >> ==35656== by 0x4E90313: __gf_free (mem-pool.c:334) > >> ==35656== by 0x4EA4E5B: synctask_destroy (syncop.c:394) > >> ==35656== by 0x4EA4EDF: synctask_done (syncop.c:412) > >> ==35656== by 0x4EA58B3: synctask_switchto (syncop.c:673) > >> ==35656== by 0x4EA596B: syncenv_processor (syncop.c:704) > >> ==35656== by 0x60B2DC4: start_thread (in /usr/lib64/ libpthread-2.17.so < > >> http://libpthread-2.17.so >) > >> ==35656== by 0x67A873C: clone (in /usr/lib64/ libc-2.17.so < > >> http://libc-2.17.so >) > >> ==35656== Address 0x1b104931 is 2,068,017 bytes inside a block of size > >> 2,097,224 alloc'd > >> ==35656== at 0x4C29975: calloc (vg_replace_malloc.c:711) > >> ==35656== by 0x4E8FA5E: __gf_calloc (mem-pool.c:117) > >> ==35656== by 0x4EA52F5: synctask_create (syncop.c:500) > >> ==35656== by 0x4EA55AE: synctask_new1 (syncop.c:576) > >> ==35656== by 0x143AE0D7: mq_synctask1 (marker-quota.c:1078) > >> ==35656== by 0x143AE199: mq_synctask (marker-quota.c:1097) > >> ==35656== by 0x143AE6F6: _mq_create_xattrs_txn (marker-quota.c:1236) > >> ==35656== by 0x143AE82D: mq_create_xattrs_txn (marker-quota.c:1253) > >> ==35656== by 0x143B0DCB: mq_inspect_directory_xattr (marker-quota.c:2027) > >> ==35656== by 0x143B13A8: mq_xattr_state (marker-quota.c:2117) > >> ==35656== by 0x143A6E80: marker_lookup_cbk (marker.c:2961) > >> ==35656== by 0x141811E0: up_lookup_cbk (upcall.c:753) > >> > >> ----------------------- valgrind > >> ------------------------------------------ > >> > >> Don't forget install valgrind-devel. > >> > >> diff --git a/libglusterfs/src/syncop.c b/libglusterfs/src/syncop.c > >> index 00a9b57..97b1de1 100644 > >> --- a/libglusterfs/src/syncop.c > >> +++ b/libglusterfs/src/syncop.c > >> @@ -10,6 +10,7 @@ > >> > >> #include "syncop.h" > >> #include "libglusterfs-messages.h" > >> +#include <valgrind/valgrind.h> > >> > >> int > >> syncopctx_setfsuid (void *uid) > >> @@ -388,6 +389,8 @@ synctask_destroy (struct synctask *task) > >> if (!task) > >> return; > >> > >> +VALGRIND_STACK_DEREGISTER(task->valgrind_ret); > >> + > >> GF_FREE (task->stack); > >> > >> if (task->opframe) > >> @@ -509,6 +512,8 @@ synctask_create (struct syncenv *env, size_t > >> stacksize, sync > >> > >> newtask->ctx.uc_stack.ss_sp = newtask->stack; > >> > >> + newtask->valgrind_ret = VALGRIND_STACK_REGISTER(newtask->stack, newtask- > >> + > >> makecontext (&newtask->ctx, (void (*)(void)) synctask_wrap, 2, newtask) > >> > >> newtask->state = SYNCTASK_INIT; > >> diff --git a/libglusterfs/src/syncop.h b/libglusterfs/src/syncop.h > >> index c2387e6..247325b 100644 > >> --- a/libglusterfs/src/syncop.h > >> +++ b/libglusterfs/src/syncop.h > >> @@ -63,6 +63,7 @@ struct synctask { > >> int woken; > >> int slept; > >> int ret; > >> + int valgrind_ret; > >> > >> uid_t uid; > >> gid_t gid; > >> diff --git a/xlators/features/marker/src/marker-quota.c > >> b/xlators/features/marke > >> index 902b8e5..f3d2507 100644 > >> --- a/xlators/features/marker/src/marker-quota.c > >> +++ b/xlators/features/marker/src/marker-quota.c > >> @@ -1075,7 +1075,7 @@ mq_synctask1 (xlator_t *this, synctask_fn_t task, > >> gf_boole > >> } > >> > >> if (spawn) { > >> - ret = synctask_new1 (this->ctx->env, 1024 * 16, task, > >> + ret = synctask_new1 (this->ctx->env, 0, task, > >> mq_synctask_cleanup, NULL, args); > >> if (ret) { > >> gf_log (this->name, GF_LOG_ERROR, "Failed to spawn " > >> > >> > >> On 6/8/2017 19:02, Sanoj Unnikrishnan wrote: > >> > I would still be worried about the Invalid read/write. IMO whether an > >> > illegal access causes a crash depends on whether the page is currently > >> > mapped. > >> > So, it could so happen that there is a use after free / use outside of > >> > bounds happening in the code and it turns out that this location gets > >> > mapped in a different (unmapped) page when IO threads is not loaded. > >> > > >> > Could you please share the valgrind logs as well. > >> > > >> > On Wed, Jun 7, 2017 at 8:22 PM, Kinglong Mee < kinglongmee@xxxxxxxxx > >> > <mailto: kinglongmee@xxxxxxxxx > <mailto: kinglongmee@xxxxxxxxx > >> > <mailto: kinglongmee@xxxxxxxxx >>> wrote: > >> > > >> > After deleting io-threads from the vols, quota operates > >> > (list/set/modify) lets glusterfsd crash. > >> > I use it at CentOS 7 (CentOS Linux release 7.3.1611) with glusterfs > >> > 3.8.12. > >> > It seems the stack corrupt, when testing with the following diff, > >> > glusterfsd runs correctly. > >> > > >> > There are two questions as, > >> > 1. When using valgrind, it shows there are many "Invalid read/write" > >> > when with io-threads. > >> > Why glusterfsd runs correctly with io-threads? but crash without > >> > io-threads? > >> > > >> > 2. With the following diff, valgrind also shows many "Invalid > >> > read/write" when without io-threads? > >> > but no any crash. > >> > > >> > Any comments are welcome. > >> > > >> > Revert http://review.gluster.org/11499 < http://review.gluster.org/11499 > >> > > < http://review.gluster.org/11499 < http://review.gluster.org/11499 > >> > >> seems better than the diff. > >> > > >> > diff --git a/xlators/features/marker/src/marker-quota.c > >> > b/xlators/features/marke > >> > index 902b8e5..f3d2507 100644 > >> > --- a/xlators/features/marker/src/marker-quota.c > >> > +++ b/xlators/features/marker/src/marker-quota.c > >> > @@ -1075,7 +1075,7 @@ mq_synctask1 (xlator_t *this, synctask_fn_t task, > >> > gf_boole > >> > } > >> > > >> > if (spawn) { > >> > - ret = synctask_new1 (this->ctx->env, 1024 * 16, task, > >> > + ret = synctask_new1 (this->ctx->env, 0, task, > >> > mq_synctask_cleanup, NULL, args); > >> > if (ret) { > >> > gf_log (this->name, GF_LOG_ERROR, "Failed to spawn " > >> > > >> > -----------------------------------test steps > >> > ---------------------------------- > >> > 1. gluster volume create gvtest node1:/test/ node2:/test/ > >> > 2. gluster volume start gvtest > >> > 3. gluster volume quota enable gvtest > >> > > >> > 4. "deletes io-threads from all vols" > >> > 5. reboot node1 and node2. > >> > 6. sh quota-set.sh > >> > > >> > # cat quota-set.sh > >> > gluster volume quota gvtest list > >> > gluster volume quota gvtest limit-usage / 10GB > >> > gluster volume quota gvtest limit-usage /1234 1GB > >> > gluster volume quota gvtest limit-usage /hello 1GB > >> > gluster volume quota gvtest limit-usage /test 1GB > >> > gluster volume quota gvtest limit-usage /xyz 1GB > >> > gluster volume quota gvtest list > >> > gluster volume quota gvtest remove /hello > >> > gluster volume quota gvtest remove /test > >> > gluster volume quota gvtest list > >> > gluster volume quota gvtest limit-usage /test 1GB > >> > gluster volume quota gvtest remove /xyz > >> > gluster volume quota gvtest list > >> > > >> > -----------------------glusterfsd crash without the > >> > diff-------------------------------- > >> > > >> > /usr/local/lib/libglusterfs.so.0(_gf_msg_backtrace_nomem+0xf5)[0x7f6e1e950af1] > >> > /usr/local/lib/libglusterfs.so.0(gf_print_trace+0x21f)[0x7f6e1e956943] > >> > /usr/local/sbin/glusterfsd(glusterfsd_print_trace+0x1f)[0x409c83] > >> > /lib64/libc.so.6(+0x35250)[0x7f6e1d025250] > >> > /lib64/libc.so.6(gsignal+0x37)[0x7f6e1d0251d7] > >> > /lib64/libc.so.6(abort+0x148)[0x7f6e1d0268c8] > >> > /lib64/libc.so.6(+0x74f07)[0x7f6e1d064f07] > >> > /lib64/libc.so.6(+0x7baf5)[0x7f6e1d06baf5] > >> > /lib64/libc.so.6(+0x7c3e6)[0x7f6e1d06c3e6] > >> > /usr/local/lib/libglusterfs.so.0(__gf_free+0x311)[0x7f6e1e981327] > >> > /usr/local/lib/libglusterfs.so.0(synctask_destroy+0x82)[0x7f6e1e995c20] > >> > /usr/local/lib/libglusterfs.so.0(synctask_done+0x25)[0x7f6e1e995c47] > >> > /usr/local/lib/libglusterfs.so.0(synctask_switchto+0xcf)[0x7f6e1e996585] > >> > /usr/local/lib/libglusterfs.so.0(syncenv_processor+0x60)[0x7f6e1e99663d] > >> > /lib64/libpthread.so.0(+0x7dc5)[0x7f6e1d7a2dc5] > >> > /lib64/libc.so.6(clone+0x6d)[0x7f6e1d0e773d] > >> > > >> > or > >> > > >> > package-string: glusterfs 3.8.12 > >> > /usr/local/lib/libglusterfs.so.0(_gf_msg_backtrace_nomem+0xf5)[0x7fa15e623af1] > >> > /usr/local/lib/libglusterfs.so.0(gf_print_trace+0x21f)[0x7fa15e629943] > >> > /usr/local/sbin/glusterfsd(glusterfsd_print_trace+0x1f)[0x409c83] > >> > /lib64/libc.so.6(+0x35250)[0x7fa15ccf8250] > >> > /lib64/libc.so.6(gsignal+0x37)[0x7fa15ccf81d7] > >> > /lib64/libc.so.6(abort+0x148)[0x7fa15ccf98c8] > >> > /lib64/libc.so.6(+0x74f07)[0x7fa15cd37f07] > >> > /lib64/libc.so.6(+0x7dd4d)[0x7fa15cd40d4d] > >> > /lib64/libc.so.6(__libc_calloc+0xb4)[0x7fa15cd43a14] > >> > /usr/local/lib/libglusterfs.so.0(__gf_calloc+0xa7)[0x7fa15e653a5f] > >> > /usr/local/lib/libglusterfs.so.0(iobref_new+0x2b)[0x7fa15e65875a] > >> > /usr/local/lib/glusterfs/3.8.12/rpc-transport/socket.so(+0xa98c)[0x7fa153a8398c] > >> > /usr/local/lib/glusterfs/3.8.12/rpc-transport/socket.so(+0xacbc)[0x7fa153a83cbc] > >> > /usr/local/lib/glusterfs/3.8.12/rpc-transport/socket.so(+0xad10)[0x7fa153a83d10] > >> > /usr/local/lib/glusterfs/3.8.12/rpc-transport/socket.so(+0xb2a7)[0x7fa153a842a7] > >> > /usr/local/lib/libglusterfs.so.0(+0x97ea9)[0x7fa15e68eea9] > >> > /usr/local/lib/libglusterfs.so.0(+0x982c6)[0x7fa15e68f2c6] > >> > /lib64/libpthread.so.0(+0x7dc5)[0x7fa15d475dc5] > >> > /lib64/libc.so.6(clone+0x6d)[0x7fa15cdba73d] > >> > > >> > _______________________________________________ > >> > Gluster-devel mailing list > >> > Gluster-devel@xxxxxxxxxxx <mailto: Gluster-devel@xxxxxxxxxxx > <mailto: > >> > Gluster-devel@xxxxxxxxxxx <mailto: Gluster-devel@xxxxxxxxxxx >> > >> > http://lists.gluster.org/mailman/listinfo/gluster-devel < > >> > http://lists.gluster.org/mailman/listinfo/gluster-devel > < > >> > http://lists.gluster.org/mailman/listinfo/gluster-devel < > >> > http://lists.gluster.org/mailman/listinfo/gluster-devel >> > >> > > >> > > >> > >> > > > > > > _______________________________________________ > Gluster-devel mailing list > Gluster-devel@xxxxxxxxxxx > http://lists.gluster.org/mailman/listinfo/gluster-devel _______________________________________________ Gluster-devel mailing list Gluster-devel@xxxxxxxxxxx http://lists.gluster.org/mailman/listinfo/gluster-devel
