The patch titled memcg: fix mem_cgroup_get_reclaim_stat_from_page has been added to the -mm tree. Its filename is memcg-fix-mem_cgroup_get_reclaim_stat_from_page.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: memcg: fix mem_cgroup_get_reclaim_stat_from_page From: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx> In case of swapin, a new page is added to lru before it is charged, so page->pc->mem_cgroup points to NULL or last mem_cgroup the page was charged before. In the latter case, if the mem_cgroup has already freed by rmdir, the area pointed to by page->pc->mem_cgroup may have invalid data. Actually, I saw general protection fault. general protection fault: 0000 [#1] SMP last sysfs file: /sys/devices/system/cpu/cpu15/cache/index1/shared_cpu_map CPU 4 Modules linked in: ipt_REJECT xt_tcpudp iptable_filter ip_tables x_tables bridge stp ipv6 autofs4 hidp rfcomm l2cap bluetooth sunrpc dm_mirror dm_region_hash dm_log dm_multipath dm_mod rfkill input_polldev sbs sbshc battery ac lp sg ide_cd_mod cdrom button serio_raw acpi_memhotplug parport_pc e1000 rtc_cmos parport rtc_core rtc_lib i2c_i801 i2c_core shpchp pcspkr ata_piix libata megaraid_mbox megaraid_mm sd_mod scsi_mod ext3 jbd ehci_hcd ohci_hcd uhci_hcd [last unloaded: microcode] Pid: 26038, comm: page01 Tainted: G W 2.6.28-rc9-mm1-mmotm-2008-12-22-16-14-f2ab3dea #1 RIP: 0010:[<ffffffff8028e710>] [<ffffffff8028e710>] update_page_reclaim_stat+0x2f/0x42 RSP: 0000:ffff8801ee457da8 EFLAGS: 00010002 RAX: 32353438312021c8 RBX: 0000000000000000 RCX: 32353438312021c8 RDX: 0000000000000000 RSI: ffff8800cb0b1000 RDI: ffff8801164d1d28 RBP: ffff880110002cb8 R08: ffff88010f2eae23 R09: 0000000000000001 R10: ffff8800bc514b00 R11: ffff880110002c00 R12: 0000000000000000 R13: ffff88000f484100 R14: 0000000000000003 R15: 00000000001200d2 FS: 00007f8a261726f0(0000) GS:ffff88010f2eaa80(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00007f8a25d22000 CR3: 00000001ef18c000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process page01 (pid: 26038, threadinfo ffff8801ee456000, task ffff8800b585b960) Stack: ffffe200071ee568 ffff880110001f00 0000000000000000 ffffffff8028ea17 ffff88000f484100 0000000000000000 0000000000000020 00007f8a25d22000 ffff8800bc514b00 ffffffff8028ec34 0000000000000000 0000000000016fd8 Call Trace: [<ffffffff8028ea17>] ? ____pagevec_lru_add+0xc1/0x13c [<ffffffff8028ec34>] ? drain_cpu_pagevecs+0x36/0x89 [<ffffffff802a4f8c>] ? swapin_readahead+0x78/0x98 [<ffffffff8029a37a>] ? handle_mm_fault+0x3d9/0x741 [<ffffffff804da654>] ? do_page_fault+0x3ce/0x78c [<ffffffff804d7a42>] ? trace_hardirqs_off_thunk+0x3a/0x3c [<ffffffff804d860f>] ? page_fault+0x1f/0x30 Code: cc 55 48 8d af b8 0d 00 00 48 89 f7 53 89 d3 e8 39 85 02 00 48 63 d3 48 ff 44 d5 10 45 85 e4 74 05 48 ff 44 d5 00 48 85 c0 74 0e <48> ff 44 d0 10 45 85 e4 74 04 48 ff 04 d0 5b 5d 41 5c c3 41 54 RIP [<ffffffff8028e710>] update_page_reclaim_stat+0x2f/0x42 RSP <ffff8801ee457da8> Signed-off-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Cc: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> Cc: Pavel Emelyanov <xemul@xxxxxxxxxx> Cc: Li Zefan <lizf@xxxxxxxxxxxxxx> Cc: Paul Menage <menage@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memcontrol.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff -puN mm/memcontrol.c~memcg-fix-mem_cgroup_get_reclaim_stat_from_page mm/memcontrol.c --- a/mm/memcontrol.c~memcg-fix-mem_cgroup_get_reclaim_stat_from_page +++ a/mm/memcontrol.c @@ -358,6 +358,10 @@ void mem_cgroup_rotate_lru_list(struct p return; pc = lookup_page_cgroup(page); + /* + * Used bit is set without atomic ops but after smp_wmb(). + * For making pc->mem_cgroup visible, insert smp_rmb() here. + */ smp_rmb(); /* unused page is not rotated. */ if (!PageCgroupUsed(pc)) @@ -374,7 +378,10 @@ void mem_cgroup_add_lru_list(struct page if (mem_cgroup_disabled()) return; pc = lookup_page_cgroup(page); - /* barrier to sync with "charge" */ + /* + * Used bit is set without atomic ops but after smp_wmb(). + * For making pc->mem_cgroup visible, insert smp_rmb() here. + */ smp_rmb(); if (!PageCgroupUsed(pc)) return; @@ -559,6 +566,14 @@ mem_cgroup_get_reclaim_stat_from_page(st return NULL; pc = lookup_page_cgroup(page); + /* + * Used bit is set without atomic ops but after smp_wmb(). + * For making pc->mem_cgroup visible, insert smp_rmb() here. + */ + smp_rmb(); + if (!PageCgroupUsed(pc)) + return NULL; + mz = page_cgroup_zoneinfo(pc); if (!mz) return NULL; _ Patches currently in -mm which might be from nishimura@xxxxxxxxxxxxxxxxx are memcg-fix-mem_cgroup_get_reclaim_stat_from_page.patch memcg-fix-error-path-of-mem_cgroup_move_parent.patch memcg-fix-hierarchical-reclaim.patch memcg-make-oom-less-frequently.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html