On 09/15/2012 12:14 AM, Sasha Levin wrote: > On 09/04/2012 11:20 AM, Michel Lespinasse wrote: >> Add a CONFIG_DEBUG_VM_RB build option for the previously existing >> DEBUG_MM_RB code. Now that Andi Kleen modified it to avoid using >> recursive algorithms, we can expose it a bit more. >> >> Also extend this code to validate_mm() after stack expansion, and to >> check that the vma's start and last pgoffs have not changed since the >> nodes were inserted on the anon vma interval tree (as it is important >> that the nodes be reindexed after each such update). > > This patch exposes the following warning: > > [ 24.977502] ------------[ cut here ]------------ > [ 24.979089] WARNING: at mm/interval_tree.c:110 > anon_vma_interval_tree_verify+0x81/0xa0() > [ 24.981765] Pid: 5928, comm: trinity-child37 Tainted: G W > 3.6.0-rc5-next-20120914-sasha-00003-g7deb7fa-dirty #333 > [ 24.985501] Call Trace: > [ 24.986345] [<ffffffff81224c91>] ? anon_vma_interval_tree_verify+0x81/0xa0 > [ 24.988535] [<ffffffff81106766>] warn_slowpath_common+0x86/0xb0 > [ 24.990636] [<ffffffff81106855>] warn_slowpath_null+0x15/0x20 > [ 24.992658] [<ffffffff81224c91>] anon_vma_interval_tree_verify+0x81/0xa0 > [ 24.994980] [<ffffffff8122e6e8>] validate_mm+0x58/0x1e0 > [ 24.996772] [<ffffffff8122e934>] vma_link+0x94/0xe0 > [ 24.997719] [<ffffffff812315e9>] copy_vma+0x279/0x2e0 > [ 24.998522] [<ffffffff8117a7fd>] ? trace_hardirqs_off+0xd/0x10 > [ 25.000772] [<ffffffff81232e89>] move_vma+0xa9/0x260 > [ 25.002499] [<ffffffff812334b5>] sys_mremap+0x475/0x540 > [ 25.004364] [<ffffffff8374b6e8>] tracesys+0xe1/0xe6 > [ 25.006108] ---[ end trace 7c901670963aa6e2 ]--- > > The code line is > > WARN_ON_ONCE(node->cached_vma_last != avc_last_pgoff(node)); > The second WARN in the function also triggers once in a while: [ 18.360283] ------------[ cut here ]------------ [ 18.360289] WARNING: at mm/interval_tree.c:109 anon_vma_interval_tree_verify+0x36/0xa0() [ 18.360292] Pid: 5694, comm: trinity-child15 Tainted: G W 3.6.0-rc5-next-20120914-sasha-00003-g7deb7fa-dirty #335 [ 18.360293] Call Trace: [ 18.360297] [<ffffffff81224c26>] ? anon_vma_interval_tree_verify+0x36/0xa0 [ 18.360300] [<ffffffff81106746>] warn_slowpath_common+0x86/0xb0 [ 18.360303] [<ffffffff81106835>] warn_slowpath_null+0x15/0x20 [ 18.360305] [<ffffffff81224c26>] anon_vma_interval_tree_verify+0x36/0xa0 [ 18.360309] [<ffffffff8122e6c8>] validate_mm+0x58/0x1e0 [ 18.360312] [<ffffffff8122e914>] vma_link+0x94/0xe0 [ 18.360315] [<ffffffff812315c9>] copy_vma+0x279/0x2e0 [ 18.360319] [<ffffffff8117a7dd>] ? trace_hardirqs_off+0xd/0x10 [ 18.360322] [<ffffffff81232e69>] move_vma+0xa9/0x260 [ 18.360326] [<ffffffff81233495>] sys_mremap+0x475/0x540 [ 18.360330] [<ffffffff8374b6e8>] tracesys+0xe1/0xe6 [ 18.360332] ---[ end trace de862a218d00cefd ]--- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>