On Sat, Jun 22, 2013 at 12:54 AM, Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote: > On Sat, Jun 22, 2013 at 12:07 AM, Davidlohr Bueso > <davidlohr.bueso@xxxxxx> wrote: >> On Fri, 2013-06-21 at 21:34 +0200, Sedat Dilek wrote: >>> On Fri, Jun 21, 2013 at 10:17 AM, Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote: >>> > Hi all, >>> > >>> > Happy solstice! >>> > >>> > Changes since 20130620: >>> > >>> > Dropped tree: mailbox (really bad merge conflicts with the arm-soc tree) >>> > >>> > The net-next tree gained a conflict against the net tree. >>> > >>> > The leds tree still had its build failure, so I used the version from >>> > next-20130607. >>> > >>> > The arm-soc tree gained conflicts against the tip, net-next, mfd and >>> > mailbox trees. >>> > >>> > The staging tree still had its build failure for which I disabled some >>> > code. >>> > >>> > The akpm tree lost a few patches that turned up elsewhere and gained >>> > conflicts against the ftrace and arm-soc trees. >>> > >>> > ---------------------------------------------------------------------------- >>> > >>> >>> [ CC IPC folks ] >>> >>> Building via 'make deb-pkg' with fakeroot fails here like this: >>> >>> make: *** [deb-pkg] Terminated >>> /usr/bin/fakeroot: line 181: 2386 Terminated >>> FAKEROOTKEY=$FAKEROOTKEY LD_LIBRARY_PATH="$PATHS" LD_PRELOAD="$LIB" >>> "$@" >>> semop(1): encountered an error: Identifier removed >>> semop(2): encountered an error: Invalid argument >>> semop(1): encountered an error: Identifier removed >>> semop(1): encountered an error: Identifier removed >>> semop(1): encountered an error: Invalid argument >>> semop(1): encountered an error: Invalid argument >>> semop(1): encountered an error: Invalid argument >>> >> >> Hmmm those really shouldn't be related to the message queue changes. Are >> you sure you got the right bisect? >> >> Manfred has a few ipc/sem.c patches in linux-next, starting at commit >> c50df1b4 (ipc/sem.c: cacheline align the semaphore structures), does >> reverting any of those instead of "ipc,msg: shorten critical region in >> msgrcv" help at all? Also, anything reported in dmesg? >> > > First, I reverted all IPC patches from akpm-tree within -next. > Then, I isolated the culprit by git-bisecting. > As I checked my logs I did not see anything helpful. > >>> The issue is present since next-20130606! >>> >>> LAST KNOWN GOOD: next-20130605 >>> FIRST KNOWN BAD: next-20130606 >>> >>> KNOWN GOOD: next-20130604 >>> KNOWN BAD: next-20130607 || next-20130619 || next-20130620 || next-20130621 >>> >>> git-bisect says CULPRIT commit is... >>> >>> "ipc,msg: shorten critical region in msgrcv" >> >> This I get. I went through the code again and it looks correct and >> functionally equivalent to the old msgrcv. >> > > Hmm, I guess a rcu_read_unlock() is missing? > > [ next-20130605 ] > ... > /* Lockless receive, part 3: > * Acquire the queue spinlock. > */ > ipc_lock_by_ptr(&msq->q_perm); > rcu_read_unlock(); > ... > [ next-20130621 ] > ... > /* Lockless receive, part 3: > * Acquire the queue spinlock. > */ > ipc_lock_object(&msq->q_perm); > ... > > Whereas ipc_lock_by_ptr() is equivalent to: > rcu_read_lock(); > ipc_lock_object(); > >>> >>> NOTE: msg_lock_(check_) routines have to be restored (one more revert needed)! >> >> This I don't get. Restoring msg_lock_[check] is already equivalent to >> reverting "ipc,msg: shorten critical region in msgrcv" and several other >> of the msq patches. What other patch needs reverted? >> > > No, you have to revert both patches as the other removed > msg_lock_[check] afterwards. > >> Anyway, I'll see if I can reproduce the issue, maybe I'm missing >> something. >> > > Yupp, I try with adding rcu_read_unlock()... and report. > > - Sedat - > >> Thanks, >> Davidlohr >> >>> >>> Reverting both (below) commits makes fakeroot build via 'make dep-pkg" again. >>> >>> I have tested the revert-patches with next-20130606 and next-20130621 >>> (see file-attachments). >>> >>> My build-script is attached! >>> >>> Can someone of the IPC folks look at that? >>> Thanks! >>> >>> - Sedat - >>> >>> >>> P.S.: Commit-IDs listed below. >>> >>> [ next-20130606 ] >>> >>> http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/log/?id=next-20130606 >>> >>> "ipc: remove unused functions" >>> http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=8793fdfb0d0a6ed5916767e29a15d3eb56e04e79 >>> >>> "ipc,msg: shorten critical region in msgrcv" >>> http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=c0ff93322847a54f74a5450032c4df64c17fdaed >>> >>> [ next-20130621 ] >>> >>> http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/log/?id=next-20130621 >>> >>> "ipc: remove unused functions" >>> http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=941ce57c81dcceadf55265616ee1e8bef18b0ad3 >>> >>> "ipc,msg: shorten critical region in msgrcv" >>> http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=62190df4081ee8504e3611d45edb40450cb408ac >> >> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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