On Tue, Jul 01, 2014 at 01:07:31PM -0400, Naoya Horiguchi wrote: > This patch makes do_mincore() use walk_page_vma(), which reduces many lines > of code by using common page table walk code. > > ChangeLog v4: > - remove redundant vma > > ChangeLog v3: > - add NULL vma check in mincore_unmapped_range() > - don't use pte_entry() > > ChangeLog v2: > - change type of args of callbacks to void * > - move definition of mincore_walk to the start of the function to fix compiler > warning > > Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> Trinity crases this implementation of mincore pretty easily: [ 42.775369] BUG: unable to handle kernel paging request at ffff88007bb61000 [ 42.776656] IP: [<ffffffff81126f8f>] mincore_unmapped_range+0xdf/0x100 [ 42.777560] PGD 2ef6067 PUD 87fa01067 PMD 87f823067 PTE 800000007bb61060 [ 42.778529] Oops: 0002 [#1] SMP DEBUG_PAGEALLOC [ 42.779106] Modules linked in: [ 42.779106] CPU: 0 PID: 917 Comm: trinity-c27 Not tainted 3.16.0-rc4-next-20140709-00013-g28e4629f71a8 #1450 [ 42.779106] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 42.779106] task: ffff880852e98110 ti: ffff880844024000 task.ti: ffff880844024000 [ 42.779106] RIP: 0010:[<ffffffff81126f8f>] [<ffffffff81126f8f>] mincore_unmapped_range+0xdf/0x100 [ 42.779106] RSP: 0018:ffff880844027df0 EFLAGS: 00010202 [ 42.779106] RAX: 000000000000001c RBX: 00007fc300000000 RCX: 00003ffffffff000 [ 42.779106] RDX: 000000000000001b RSI: ffff88007bb60fe5 RDI: 00007fc2c2c00000 [ 42.779106] RBP: ffff880844027e28 R08: 00007fc2c2e00000 R09: 0000000000000000 [ 42.779106] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000200 [ 42.779106] R13: ffff88007bb60fe5 R14: ffff880855a80018 R15: 00007fc2c2c00000 [ 42.779106] FS: 00007fc345666700(0000) GS:ffff880859600000(0000) knlGS:0000000000000000 [ 42.779106] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 42.779106] CR2: ffff88007bb61000 CR3: 0000000852dfd000 CR4: 00000000000006f0 [ 42.779106] Stack: [ 42.779106] ffff880844027f10 ffff88007bb60fe5 00007fc300000000 00007fc2c2e00000 [ 42.779106] 00007fc2c1e1b000 ffff880844027f10 00007fc2c2c00000 ffff880844027eb8 [ 42.779106] ffffffff81135bfe 00007fc341c1bfff ffff880000000000 ffff880852dfd7f8 [ 42.779106] Call Trace: [ 42.779106] [<ffffffff81135bfe>] __walk_page_range+0x1ae/0x450 [ 42.779106] [<ffffffff81136051>] walk_page_vma+0x71/0x90 [ 42.779106] [<ffffffff8112741e>] SyS_mincore+0x1de/0x270 [ 42.779106] [<ffffffff810949fd>] ? trace_hardirqs_on+0xd/0x10 [ 42.779106] [<ffffffff81126fb0>] ? mincore_unmapped_range+0x100/0x100 [ 42.779106] [<ffffffff81126eb0>] ? mincore_page+0xa0/0xa0 [ 42.779106] [<ffffffff81126dc0>] ? handle_mm_fault+0xd30/0xd30 [ 42.779106] [<ffffffff81746b52>] system_call_fastpath+0x16/0x1b [ 42.779106] Code: 83 c4 10 31 c0 5b 41 5c 41 5d 41 5e 41 5f 5d c3 0f 1f 40 00 31 d2 31 c0 4d 85 e4 4c 8b 6d d0 74 d3 0f 1f 00 48 8b 75 d0 83 c0 01 <c6> 04 16 00 48 63 d0 49 39 d4 77 ed eb b3 48 89 fe 4c 89 f7 e8 [ 42.779106] RIP [<ffffffff81126f8f>] mincore_unmapped_range+0xdf/0x100 [ 42.779106] RSP <ffff880844027df0> [ 42.779106] CR2: ffff88007bb61000 [ 42.779106] ---[ end trace 3fac62521b6b0cb0 ]--- [ 42.779106] Kernel panic - not syncing: Fatal exception [ 42.779106] Kernel Offset: 0x0 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffff9fffffff) Looks like 'vec' overflow. I don't see what could prevent do_mincore() to write more than PAGE_SIZE to 'vec'. -- Kirill A. Shutemov -- 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>