From 55fe07ad98315d9471a86affd0680749e349a0a6 Mon Sep 17 00:00:00 2001 From: Zdenek Kabelac Date: Mon, 13 May 2013 12:59:38 +0200 Subject: [PATCH] mm: fix leak in fail path If the dm_realloc would fail, the already allocate _maps_buffer memory would have been lost (overwritten with NULL). Fix this by using temporary line buffer. Also add a minor cleanup to set end of buffer to '\0', only when we really know the file size fits the preallocated buffer. --- WHATS_NEW | 1 + lib/mm/memlock.c | 19 +++++++++++-------- 2 files changed, 12 insertions(+), 8 deletions(-) diff --git a/WHATS_NEW b/WHATS_NEW index 2cdd0cdda..11d3e6fd8 100644 --- a/WHATS_NEW +++ b/WHATS_NEW @@ -1,5 +1,6 @@ Version 2.02.99 - =================================== + Fix memory resource leak in memlocking error path. Fix premature DM version checking which caused useless mapper/control access. Add "active" LV reporting field to show activation state. Add "monitor" segment reporting field to show dmevent monitoring status. diff --git a/lib/mm/memlock.c b/lib/mm/memlock.c index 098de9e44..08876b0e6 100644 --- a/lib/mm/memlock.c +++ b/lib/mm/memlock.c @@ -270,23 +270,26 @@ static int _memlock_maps(struct cmd_context *cmd, lvmlock_t lock, size_t *mstats if (!_maps_buffer || len >= _maps_len) { if (_maps_buffer) _maps_len *= 2; - if (!(_maps_buffer = dm_realloc(_maps_buffer, _maps_len))) { - log_error("Allocation of maps buffer failed"); + if (!(line = dm_realloc(_maps_buffer, _maps_len))) { + log_error("Allocation of maps buffer failed."); return 0; } + _maps_buffer = line; } if (lseek(_maps_fd, 0, SEEK_SET)) log_sys_error("lseek", _procselfmaps); for (len = 0 ; len < _maps_len; len += n) { - if (!(n = read(_maps_fd, _maps_buffer + len, _maps_len - len))) { - _maps_buffer[len] = '\0'; + if (!(n = read(_maps_fd, _maps_buffer + len, _maps_len - len))) break; /* EOF */ + if (n == -1) { + log_sys_error("read", _procselfmaps); + return 0; } - if (n == -1) - return_0; } - if (len < _maps_len) /* fits in buffer */ + if (len < _maps_len) { /* fits in buffer */ + _maps_buffer[len] = '\0'; break; + } } line = _maps_buffer; @@ -315,7 +318,7 @@ static void _lock_mem(struct cmd_context *cmd) * so even future adition of thread which may not even use lvm lib * will not block memory locked thread * Note: assuming _memlock_count_daemon is updated before _memlock_count - */ + */ _use_mlockall = _memlock_count_daemon ? 1 : find_config_tree_bool(cmd, activation_use_mlockall_CFG); -- 2.43.5