June 2014 - ghc-tickets

Re: [GHC] #4934: threadWaitRead works incorrectly on nonthreaded RTS
by GHC 06 Jun '14

06 Jun '14

#4934: threadWaitRead works incorrectly on nonthreaded RTS ------------------------------------------------+-------------------------- Reporter: slyfox | Owner: Type: bug | Status: patch Priority: normal | Milestone: ⊥ Component: Runtime System | Version: 7.0.1 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Incorrect result at runtime | (amd64) Test Case: | Difficulty: Blocking: | Unknown | Blocked By: | Related Tickets: ------------------------------------------------+-------------------------- Comment (by slyfox): > Yes, please squash the patches and then I'll review. Will do. > Not sure what you mean by "slightly change polling cycle to resume only descriptors with data available", don't we already do that? I was a bit unclear. I meant: only in a case of '''select() == EBADF''' failure we always resumed all the blocked threads: https://ghc.haskell.org/trac/ghc/browser/ghc/rts/posix/Select.c#L295 {{{ if ( errno == EBADF ) unblock_all = rtsTrue; ... ready = unblock_all || FD_ISSET(tso->block_info.fd, &rfd); // [1] ... if (ready) pushOnRunQueue(&MainCapability,tso); }}} Current patchset only propagates exceptions early, but does not fix spurious resumes (as it was before). I propose to fix resume problem: {{{ --- ready = unblock_all || FD_ISSET(tso->block_info.fd, &rfd); +++ if (unblock_all) ready = fd_is_really_ready (fd); +++ else ready = FD_ISSET(tso->block_info.fd, &rfd); }}} It' won't be hard to implement on top of current patchset. Secondary '''select()''' can already provide all the info. Should I do it as a) a separate patch/ticket, b) merge into final result, c) don't touch it at all? Thanks! -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4934#comment:23> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #1388: Newbie help features
by GHC 06 Jun '14

06 Jun '14

#1388: Newbie help features -------------------------------+------------------------------------------- Reporter: guest | Owner: Type: feature | Status: new request | Milestone: ⊥ Priority: low | Version: 6.6.1 Component: GHCi | Keywords: Resolution: | Architecture: Unknown/Multiple Operating System: | Difficulty: Easy (less than 1 hour) Unknown/Multiple | Blocked By: Type of failure: | Related Tickets: None/Unknown | Test Case: | Blocking: | -------------------------------+------------------------------------------- Comment (by nomeata): Split the last suggestion in the original ticket to #9177 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1388#comment:7> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4934: threadWaitRead works incorrectly on nonthreaded RTS
by GHC 06 Jun '14

06 Jun '14

#4934: threadWaitRead works incorrectly on nonthreaded RTS ------------------------------------------------+-------------------------- Reporter: slyfox | Owner: Type: bug | Status: patch Priority: normal | Milestone: ⊥ Component: Runtime System | Version: 7.0.1 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Incorrect result at runtime | (amd64) Test Case: | Difficulty: Blocking: | Unknown | Blocked By: | Related Tickets: ------------------------------------------------+-------------------------- Comment (by simonmar): Yes, please squash the patches and then I'll review. Not sure what you mean by "slightly change polling cycle to resume only descriptors with data available", don't we already do that? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4934#comment:22> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4934: threadWaitRead works incorrectly on nonthreaded RTS
by GHC 06 Jun '14

06 Jun '14

#4934: threadWaitRead works incorrectly on nonthreaded RTS ------------------------------------------------+-------------------------- Reporter: slyfox | Owner: Type: bug | Status: patch Priority: normal | Milestone: ⊥ Component: Runtime System | Version: 7.0.1 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Incorrect result at runtime | (amd64) Test Case: | Difficulty: Blocking: | Unknown | Blocked By: | Related Tickets: ------------------------------------------------+-------------------------- Comment (by slyfox): If idea in patches looks fine i can squash last 3 patches in one and cleanup comments around. I can also slightly change polling cycle to resume only descriptors with data available, and not all the waiters. It would be more robust against spurious blocking calls. What do you think? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4934#comment:21> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4934: threadWaitRead works incorrectly on nonthreaded RTS
by GHC 05 Jun '14

05 Jun '14

#4934: threadWaitRead works incorrectly on nonthreaded RTS ------------------------------------------------+-------------------------- Reporter: slyfox | Owner: Type: bug | Status: patch Priority: normal | Milestone: ⊥ Component: Runtime System | Version: 7.0.1 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Incorrect result at runtime | (amd64) Test Case: | Difficulty: Blocking: | Unknown | Blocked By: | Related Tickets: ------------------------------------------------+-------------------------- Changes (by slyfox): * status: new => patch Comment: Now even with non-threaded RTS error is reported as expected: {{{ $ inplace/bin/ghc-stage2 --make -fforce-recomp a.hs -o a -debug && ./a a: awaitEvent: invalid argument (Bad file descriptor) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4934#comment:20> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4934: threadWaitRead works incorrectly on nonthreaded RTS
by GHC 05 Jun '14

05 Jun '14

#4934: threadWaitRead works incorrectly on nonthreaded RTS ------------------------------------------------+-------------------------- Reporter: slyfox | Owner: Type: bug | Status: new Priority: normal | Milestone: ⊥ Component: Runtime System | Version: 7.0.1 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Incorrect result at runtime | (amd64) Test Case: | Difficulty: Blocking: | Unknown | Blocked By: | Related Tickets: ------------------------------------------------+-------------------------- Comment (by slyfox): After throwToSingleThreaded '''tso''' should not be pushed to runnables queue. 0004-rts-posix-Select.c-don-t-put-thread-with-pending-exc.patch fixes this problem. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4934#comment:19> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4934: threadWaitRead works incorrectly on nonthreaded RTS
by GHC 05 Jun '14

05 Jun '14

#4934: threadWaitRead works incorrectly on nonthreaded RTS ------------------------------------------------+-------------------------- Reporter: slyfox | Owner: Type: bug | Status: new Priority: normal | Milestone: ⊥ Component: Runtime System | Version: 7.0.1 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Incorrect result at runtime | (amd64) Test Case: | Difficulty: Blocking: | Unknown | Blocked By: | Related Tickets: ------------------------------------------------+-------------------------- Comment (by slyfox): Some notes about the code which does '''threadWaitRead''' from haskell, but does not perform '''read()'''. For xmobar the bug was in polling on X11 socket from haskell code, and handling of sockets from C code (which ignored bad FD). Thus such code led to 100% CPU busy loop: {{{ x11_ctx <- get_x11_ctx forever $ do threadWaitRead (x11_connection x11_ctx) x11_poll_events event_callback -- ignores -EBADF }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4934#comment:18> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4934: threadWaitRead works incorrectly on nonthreaded RTS
by GHC 05 Jun '14

05 Jun '14

#4934: threadWaitRead works incorrectly on nonthreaded RTS ------------------------------------------------+-------------------------- Reporter: slyfox | Owner: Type: bug | Status: new Priority: normal | Milestone: ⊥ Component: Runtime System | Version: 7.0.1 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Incorrect result at runtime | (amd64) Test Case: | Difficulty: Blocking: | Unknown | Blocked By: | Related Tickets: ------------------------------------------------+-------------------------- Comment (by slyfox): 0003-rts-posix-Select.c-throw-exception-to-reader-as-soon.patch adds another step to kill thread on '''threadWaitRead'''. Now it works as: {{{ [1 of 1] Compiling Main ( a.hs, a.o ) Linking a ... a: awaitEvent: invalid argument (Bad file descriptor) a: user error (If you can read this, shutdownHaskellAndExit did not exit.) }}} The problem is the status of killed thread. RTS thinks it did not finish, but blocked on FFI call: {{{ $ ./a +RTS -D{s,i,r,S,z} cap 0: thread 1 stopped (blocked on a read operation) thread 1 @ 0x7fd2fa405390 is blocked on read from fd 12 (TSO_DIRTY) scheduler: checking for threads blocked on I/O (waiting) found bad READ fd=12 cap 0: raising exception in thread 1. Waking up blocked thread 1 cap 0: running thread 1 (ThreadRunGHC) a: awaitEvent: invalid argument (Bad file descriptor) cap 0: thread 1 stopped (suspended while making a foreign call) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4934#comment:17> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7241: GHC-7.6.1 panics on template haskell code
by GHC 05 Jun '14

05 Jun '14

#7241: GHC-7.6.1 panics on template haskell code ---------------------------------------+----------------------------------- Reporter: akamaus | Owner: Yuras Type: bug | Status: merge Priority: normal | Milestone: 7.8.3 Component: Template Haskell | Version: 7.6.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time crash | Unknown/Multiple Test Case: | Difficulty: Unknown Blocking: | Blocked By: | Related Tickets: ---------------------------------------+----------------------------------- Changes (by thoughtpolice): * status: patch => merge -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7241#comment:10> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7241: GHC-7.6.1 panics on template haskell code
by GHC 05 Jun '14

05 Jun '14

#7241: GHC-7.6.1 panics on template haskell code ---------------------------------------+----------------------------------- Reporter: akamaus | Owner: Yuras Type: bug | Status: patch Priority: normal | Milestone: 7.8.3 Component: Template Haskell | Version: 7.6.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time crash | Unknown/Multiple Test Case: | Difficulty: Unknown Blocking: | Blocked By: | Related Tickets: ---------------------------------------+----------------------------------- Comment (by Austin Seipp <austin@…>): In [changeset:"c226d25fef519db663d0c9efe7845637423f1dca/ghc"]: {{{ #!CommitTicketReference repository="ghc" revision="c226d25fef519db663d0c9efe7845637423f1dca" Emit error in case of duplicate GRE; fixes #7241 Signed-off-by: Austin Seipp <austin(a)well-typed.com> }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7241#comment:9> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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