From 83258e33852166a3111a009f1720cc87f62efc73 Mon Sep 17 00:00:00 2001 From: Zdenek Kabelac Date: Fri, 9 Feb 2018 00:26:22 +0100 Subject: [PATCH] toolcontext: do not change stream for pthreaded programs With pthreaded daemons like 'dmeventd' using liblvm via plugin, lvm2 actually should not 'play' with streams at all - as there could be parallel outputs running. As a current quick workaround just disable change for pthreaded program (gettid() != getpid()). TODO: it's possible the change of buffering actually doesn't serve us any measurable benefit and could be dropped as whole later... Meanwhile this patch is fixing this occasional valgrind race report: Invalid read of size 4 at 0x571892C: vfprintf (in /usr/lib64/libc-2.26.9000.so) by 0x57216B3: fprintf (in /usr/lib64/libc-2.26.9000.so) by 0x5042886: dm_event_log (libdevmapper-event.c:925) by 0x10B015: _dmeventd_log (dmeventd.c:125) by 0x10D289: _unregister_for_event (dmeventd.c:1146) by 0x10E52E: _handle_request (dmeventd.c:1583) by 0x10E6D7: _do_process_request (dmeventd.c:1631) by 0x10E7C6: _process_request (dmeventd.c:1660) by 0x1101A4: main (dmeventd.c:2285) Address 0x6264d30 is 192 bytes inside a block of size 552 free'd at 0x4C2ED68: free (vg_replace_malloc.c:530) by 0x573907D: fclose@@GLIBC_2.2.5 (in /usr/lib64/libc-2.26.9000.so) by 0x6AC5C00: reopen_standard_stream (log.c:189) by 0x6A8E62C: destroy_toolcontext (toolcontext.c:2271) by 0x6BA5C22: lvm_fin (lvmcmdline.c:3339) by 0x6BD5EF3: lvm2_exit (lvmcmdlib.c:123) by 0x6856013: dmeventd_lvm2_exit (dmeventd_lvm.c:103) by 0x66535B8: unregister_device (dmeventd_thin.c:432) by 0x10CBBC: _do_unregister_device (dmeventd.c:926) by 0x10CD74: _monitor_unregister (dmeventd.c:979) by 0x10D094: _monitor_thread (dmeventd.c:1066) by 0x54B35E0: start_thread (in /usr/lib64/libpthread-2.26.9000.so) by 0x57C30EE: clone (in /usr/lib64/libc-2.26.9000.so) Block was alloc'd at at 0x4C2DBBB: malloc (vg_replace_malloc.c:299) by 0x573932B: fdopen@@GLIBC_2.2.5 (in /usr/lib64/libc-2.26.9000.so) by 0x6AC5DC2: reopen_standard_stream (log.c:200) by 0x6A8D11D: create_toolcontext (toolcontext.c:1898) by 0x6BA5B6B: init_lvm (lvmcmdline.c:3319) by 0x6BD5BC8: cmdlib_lvm2_init (lvmcmdlib.c:34) by 0x6BD5F04: lvm2_init (lvm2cmd.c:20) by 0x6855EA7: dmeventd_lvm2_init (dmeventd_lvm.c:67) by 0x665305F: register_device (dmeventd_thin.c:352) by 0x10CB7A: _do_register_device (dmeventd.c:916) by 0x10CEE4: _monitor_thread (dmeventd.c:1006) by 0x54B35E0: start_thread (in /usr/lib64/libpthread-2.26.9000.so) by 0x57C30EE: clone (in /usr/lib64/libc-2.26.9000.so) .... Process terminating with default action of signal 6 (SIGABRT): dumping core at 0x570016B: raise (in /usr/lib64/libc-2.26.9000.so) by 0x5701520: abort (in /usr/lib64/libc-2.26.9000.so) by 0x57437D8: __libc_message (in /usr/lib64/libc-2.26.9000.so) by 0x5743831: __libc_fatal (in /usr/lib64/libc-2.26.9000.so) by 0x5744056: _IO_vtable_check (in /usr/lib64/libc-2.26.9000.so) by 0x574751C: __overflow (in /usr/lib64/libc-2.26.9000.so) by 0x574191A: fputc (in /usr/lib64/libc-2.26.9000.so) by 0x50428E3: dm_event_log (libdevmapper-event.c:934) by 0x10B015: _dmeventd_log (dmeventd.c:125) by 0x10D289: _unregister_for_event (dmeventd.c:1146) by 0x10E52E: _handle_request (dmeventd.c:1583) by 0x10E6D7: _do_process_request (dmeventd.c:1631) by 0x10E7C6: _process_request (dmeventd.c:1660) by 0x1101A4: main (dmeventd.c:2285) --- WHATS_NEW | 1 + lib/commands/toolcontext.c | 11 +++++++++-- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/WHATS_NEW b/WHATS_NEW index 197adc30b..bf46281bf 100644 --- a/WHATS_NEW +++ b/WHATS_NEW @@ -1,5 +1,6 @@ Version 2.02.178 - ===================================== + Do not reopen output streams for multithreaded users of liblvm. Use versionsort to fix archive file expiry beyond 100000 files. Add devices/use_aio, aio_max, aio_memory to configure AIO limits. Support asynchronous I/O when scanning devices. diff --git a/lib/commands/toolcontext.c b/lib/commands/toolcontext.c index 0080a6828..ba757ddd6 100644 --- a/lib/commands/toolcontext.c +++ b/lib/commands/toolcontext.c @@ -46,6 +46,7 @@ #include #include +#include #include #include #include @@ -1883,7 +1884,13 @@ struct cmd_context *create_toolcontext(unsigned is_long_lived, #ifndef VALGRIND_POOL /* Set in/out stream buffering before glibc */ - if (set_buffering) { + if (set_buffering +#ifdef SYS_gettid + /* For threaded programs no changes of streams */ + /* On linux gettid() is implemented only via syscall */ + && (syscall(SYS_gettid) == getpid()) +#endif + ) { /* Allocate 2 buffers */ if (!(cmd->linebuffer = dm_malloc(2 * _linebuffer_size))) { log_error("Failed to allocate line buffer."); @@ -1914,7 +1921,7 @@ struct cmd_context *create_toolcontext(unsigned is_long_lived, } } /* Buffers are used for lines without '\n' */ - } else + } else if (!set_buffering) /* Without buffering, must not use stdin/stdout */ init_silent(1); #endif -- 2.43.5