Bug #16492 Updated: php_passthru_fd() which uses mmap() crashes machine

ID: 16492 Updated by: fuf@mobil.cz Reported By: fuf@mobil.cz Status: Open Bug Type: Reproducible crash Operating System: linux 2.2.x, 2.4.x PHP Version: 4.1.2 New Comment: just another important note: the server crashes occured only after it'd been running for 2 days (not sooner). during that time we noticed much heavier memory usage (swap was used and the memory used in buffers (cached) was just 1MB below the physical memory, now the swap is not used at all and memory used in buffers is ~100MB below the physical memory). also the crashes occured independently of kernel version. we tried 2.2.17-18 and 2.4.18. thanks, Michal Vitecek Previous Comments: ------------------------------------------------------------------------ [2002-04-08 08:24:54] fuf@mobil.cz hello, short: function fd_passthru_fd() which uses the mmap() function to read a file contents crashes the whole machine after 2 days of heavy use. with #undef HAVE_MMAP the machine is rock solid. long: we have a dual cpu download server that uses apache and a php script to control access to files. the script first checks whether the user is allowed to download a desired file and then sends it to the user with the use of function readfile(). however with HAVE_MMAP = 1 and thus a different code in php_passthru_fd() the server crashed repeatedly with this kernel message: Oops: 0000 CPU: 1 EIP: 0010:[kmem_cache_free+64/436] EFLAGS: 00010086 eax: d7fff020 ebx: d7fff020 ecx: 7dd3035c edx: cd76e95c esi: cd76e920 edi: 00000292 ebp: d7fff260 esp: d7fe1f1c ds: 0018 es: 0018 ss: 0018 Process kswapd (pid: 4, process nr: 5, stackpage=d7fe1000) Stack: ce32c000 d7fff260 00000000 c036e6e0 c0100018 00000202 ffffff09 c0126dda 00000010 c0125cdc d7fff020 cd76e920 d7fe0000 c0125cc7 d7fe0000 00000020 d7fe02c5 00000030 c036e3e8 c0120bff 00000010 d7fff268 c0266fc0 00000000 Call Trace: [startup_32+24/169] [__free_pages+282/356] [kmem_cache_reap+684/744] [kmem_cache_reap+663/744] [ shrink_mmap+139/476] [try_to_free_pages+108/260] [tvecs+6062/13120] [tvecs+6062/13120] [kswapd+106/160] [kswapd+82/160] [kernel_thread+31/56] [kernel_thread+40/56] Code: 8b 41 08 3d 2b 2f c3 a5 0f 85 ee 00 00 00 8b 41 0c 85 c0 74 after having #undef'ed HAVE_MMAP the machine runs all okay (even under much heavier load). i'm not sure whether this is a php or kernel related bug, but i guess you'd be interested. thanks, Michal Vitecek ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=16492&edit=1