(switched to email. Please respond via emailed reply-to-all, not via the bugzilla web interface). On Tue, 19 Apr 2011 05:25:41 GMT bugzilla-daemon@xxxxxxxxxxxxxxxxxxx wrote: > https://bugzilla.kernel.org/show_bug.cgi?id=33682 > > Summary: mprotect got stuck when THP is "always" enabled > Product: Memory Management > Version: 2.5 > Kernel Version: 2.6.38-r1 > Platform: All > OS/Version: Linux > Tree: Mainline > Status: NEW > Severity: normal > Priority: P1 > Component: Other > AssignedTo: akpm@xxxxxxxxxxxxxxxxxxxx > ReportedBy: bugs@xxxxxxxxxxxxxxx > Regression: No > > > Created an attachment (id=54662) > --> (https://bugzilla.kernel.org/attachment.cgi?id=54662) > mprotect test program > > Description of problem: > > see attached test program. This program can be run like this: > > ./mprotect <times> <length> <flag> > > times: how many times the mprotect() function execute; > length: same as the "length" option in mprotect() function; > flag: when flag is set to 1, the program would touch every page within the > range [addr, addr+length-1] before it calls mprotect(). > > to reproduce the stuck, execute: ./mprotect 50 128 1 > > Note that the stuck only happens when the following conditions are all > satisfied: > > flag == 1, i.e. touch page before mprotect() > proto = PROT_NONE in mprotect() > THP is enabled with "always" option > > Version-Release number of selected component (if applicable): > > Linux version 2.6.39-rc3 (caspar@caspar-gentoo) (gcc version 4.5.2 (Gentoo > 4.5.2 p1.0, pie-0.4.5) ) #1 SMP Tue Apr 19 12:32:20 CST 2011 > > How reproducible: > very often > > Actual results: > test program got stuck when touching pages + THP always enabled: > > caspar-gentoo tmp # echo always > /sys/kernel/mm/transparent_hugepage/enabled > caspar-gentoo tmp # ./mprotect 50 128 1 > ^C <- stuck > caspar-gentoo tmp # ./mprotect 50 128 1 > ^C > caspar-gentoo tmp # ./mprotect 50 128 1 > ^C > caspar-gentoo tmp # ./mprotect 50 128 1 > ^C > caspar-gentoo tmp # echo madvise > /sys/kernel/mm/transparent_hugepage/enabled > caspar-gentoo tmp # ./mprotect 50 128 1 > done caspar-gentoo tmp # ./mprotect 50 128 1 > done caspar-gentoo tmp # ./mprotect 50 128 1 > done caspar-gentoo tmp # ./mprotect 50 128 1 > done caspar-gentoo tmp # echo never > > /sys/kernel/mm/transparent_hugepage/enabled > caspar-gentoo tmp # ./mprotect 50 128 1 > done caspar-gentoo tmp # ./mprotect 50 128 1 > done caspar-gentoo tmp # ./mprotect 50 128 1 > done caspar-gentoo tmp # ./mprotect 50 128 1 > done caspar-gentoo tmp # ./mprotect 50 128 1 > done caspar-gentoo tmp # ./mprotect 50 128 1 > done caspar-gentoo tmp # ./mprotect 50 128 1 > > Expected results: > test program exit normally > > Additional info: > > This reproducer was similar to a test program in upstream test suite: libMicro > (http://hub.opensolaris.org/bin/view/Project+libmicro/) > > strace ouput: > > # strace ./mprotect 50 128 1 > execve("./mprotect", ["./mprotect", "50", "128", "1"], [/* 35 vars */]) = 0 > brk(0) = 0x16ad000 > mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = > 0x7ffa0c266000 > access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) > open("/etc/ld.so.cache", O_RDONLY) = 3 > fstat(3, {st_mode=S_IFREG|0644, st_size=163815, ...}) = 0 > mmap(NULL, 163815, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7ffa0c23e000 > close(3) = 0 > open("/lib64/libc.so.6", O_RDONLY) = 3 > read(3, > "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\320\357\1\0\0\0\0\0"..., 832) = > 832 > fstat(3, {st_mode=S_IFREG|0755, st_size=1608912, ...}) = 0 > mmap(NULL, 3718152, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = > 0x7ffa0bcbc000 > mprotect(0x7ffa0be3f000, 2093056, PROT_NONE) = 0 > mmap(0x7ffa0c03e000, 20480, PROT_READ|PROT_WRITE, > MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x182000) = 0x7ffa0c03e000 > mmap(0x7ffa0c043000, 19464, PROT_READ|PROT_WRITE, > MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7ffa0c043000 > close(3) = 0 > mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = > 0x7ffa0c23d000 > mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = > 0x7ffa0c23c000 > mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = > 0x7ffa0c23b000 > arch_prctl(ARCH_SET_FS, 0x7ffa0c23c700) = 0 > mprotect(0x7ffa0c03e000, 16384, PROT_READ) = 0 > mprotect(0x600000, 4096, PROT_READ) = 0 > mprotect(0x7ffa0c267000, 4096, PROT_READ) = 0 > munmap(0x7ffa0c23e000, 163815) = 0 > open("/dev/zero", O_RDWR) = 3 > mmap(NULL, 6553600, PROT_READ|PROT_WRITE, MAP_PRIVATE, 3, 0) = 0x7ffa0b67c000 > mprotect(0x7ffa0b67c000, 131072, PROT_NONE) = 0 > mprotect(0x7ffa0b69c000, 131072, PROT_NONE) = 0 > mprotect(0x7ffa0b6bc000, 131072, PROT_NONE) = 0 > mprotect(0x7ffa0b6dc000, 131072, PROT_NONE) = 0 > mprotect(0x7ffa0b6fc000, 131072, PROT_NONE) = 0 > mprotect(0x7ffa0b71c000, 131072, PROT_NONE) = 0 > mprotect(0x7ffa0b73c000, 131072, PROT_NONE) = 0 > mprotect(0x7ffa0b75c000, 131072, PROT_NONE) = 0 > <repeated random times, snip> > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . 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