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c25f195e82
In the -rt kernel (mrg), we hit the following dump: BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<ffffffff811573f1>] kmem_cache_alloc_node+0x51/0x180 PGD a2d39067 PUD b1641067 PMD 0 Oops: 0000 [#1] PREEMPT SMP Modules linked in: sunrpc cpufreq_ondemand ipv6 tg3 joydev sg serio_raw pcspkr k8temp amd64_edac_mod edac_core i2c_piix4 e100 mii shpchp ext4 mbcache jbd2 sd_mod crc_t10dif sr_mod cdrom sata_svw ata_generic pata_acpi pata_serverworks radeon ttm drm_kms_helper drm hwmon i2c_algo_bit i2c_core dm_mirror dm_region_hash dm_log dm_mod CPU 3 Pid: 20878, comm: hackbench Not tainted 3.6.11-rt25.14.el6rt.x86_64 #1 empty empty/Tyan Transport GT24-B3992 RIP: 0010:[<ffffffff811573f1>] [<ffffffff811573f1>] kmem_cache_alloc_node+0x51/0x180 RSP: 0018:ffff8800a9b17d70 EFLAGS: 00010213 RAX: 0000000000000000 RBX: 0000000001200011 RCX: ffff8800a06d8000 RDX: 0000000004d92a03 RSI: 00000000000000d0 RDI: ffff88013b805500 RBP: ffff8800a9b17dc0 R08: ffff88023fd14d10 R09: ffffffff81041cbd R10: 00007f4e3f06e9d0 R11: 0000000000000246 R12: ffff88013b805500 R13: ffff8801ff46af40 R14: 0000000000000001 R15: 0000000000000000 FS: 00007f4e3f06e700(0000) GS:ffff88023fd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000000 CR3: 00000000a2d3a000 CR4: 00000000000007e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process hackbench (pid: 20878, threadinfo ffff8800a9b16000, task ffff8800a06d8000) Stack: ffff8800a9b17da0 ffffffff81202e08 ffff8800a9b17de0 000000d001200011 0000000001200011 0000000001200011 0000000000000000 0000000000000000 00007f4e3f06e9d0 0000000000000000 ffff8800a9b17e60 ffffffff81041cbd Call Trace: [<ffffffff81202e08>] ? current_has_perm+0x68/0x80 [<ffffffff81041cbd>] copy_process+0xdd/0x15b0 [<ffffffff810a2125>] ? rt_up_read+0x25/0x30 [<ffffffff8104369a>] do_fork+0x5a/0x360 [<ffffffff8107c66b>] ? migrate_enable+0xeb/0x220 [<ffffffff8100b068>] sys_clone+0x28/0x30 [<ffffffff81527423>] stub_clone+0x13/0x20 [<ffffffff81527152>] ? system_call_fastpath+0x16/0x1b Code: 89 fc 89 75 cc 41 89 d6 4d 8b 04 24 65 4c 03 04 25 48 ae 00 00 49 8b 50 08 4d 8b 28 49 8b 40 10 4d 85 ed 74 12 41 83 fe ff 74 27 <48> 8b 00 48 c1 e8 3a 41 39 c6 74 1b 8b 75 cc 4c 89 c9 44 89 f2 RIP [<ffffffff811573f1>] kmem_cache_alloc_node+0x51/0x180 RSP <ffff8800a9b17d70> CR2: 0000000000000000 ---[ end trace 0000000000000002 ]--- Now, this uses SLUB pretty much unmodified, but as it is the -rt kernel with CONFIG_PREEMPT_RT set, spinlocks are mutexes, although they do disable migration. But the SLUB code is relatively lockless, and the spin_locks there are raw_spin_locks (not converted to mutexes), thus I believe this bug can happen in mainline without -rt features. The -rt patch is just good at triggering mainline bugs ;-) Anyway, looking at where this crashed, it seems that the page variable can be NULL when passed to the node_match() function (which does not check if it is NULL). When this happens we get the above panic. As page is only used in slab_alloc() to check if the node matches, if it's NULL I'm assuming that we can say it doesn't and call the __slab_alloc() code. Is this a correct assumption? Acked-by: Christoph Lameter <cl@linux.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Pekka Enberg <penberg@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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| .. | ||
| backing-dev.c | ||
| balloon_compaction.c | ||
| bootmem.c | ||
| bounce.c | ||
| cleancache.c | ||
| compaction.c | ||
| debug-pagealloc.c | ||
| dmapool.c | ||
| fadvise.c | ||
| failslab.c | ||
| filemap_xip.c | ||
| filemap.c | ||
| fremap.c | ||
| frontswap.c | ||
| highmem.c | ||
| huge_memory.c | ||
| hugetlb_cgroup.c | ||
| hugetlb.c | ||
| hwpoison-inject.c | ||
| init-mm.c | ||
| internal.h | ||
| interval_tree.c | ||
| Kconfig | ||
| Kconfig.debug | ||
| kmemcheck.c | ||
| kmemleak-test.c | ||
| kmemleak.c | ||
| ksm.c | ||
| maccess.c | ||
| madvise.c | ||
| Makefile | ||
| memblock.c | ||
| memcontrol.c | ||
| memory_hotplug.c | ||
| memory-failure.c | ||
| memory.c | ||
| mempolicy.c | ||
| mempool.c | ||
| migrate.c | ||
| mincore.c | ||
| mlock.c | ||
| mm_init.c | ||
| mmap.c | ||
| mmu_context.c | ||
| mmu_notifier.c | ||
| mmzone.c | ||
| mprotect.c | ||
| mremap.c | ||
| msync.c | ||
| nobootmem.c | ||
| nommu.c | ||
| oom_kill.c | ||
| page_alloc.c | ||
| page_cgroup.c | ||
| page_io.c | ||
| page_isolation.c | ||
| page-writeback.c | ||
| pagewalk.c | ||
| percpu-km.c | ||
| percpu-vm.c | ||
| percpu.c | ||
| pgtable-generic.c | ||
| process_vm_access.c | ||
| quicklist.c | ||
| readahead.c | ||
| rmap.c | ||
| shmem.c | ||
| slab_common.c | ||
| slab.c | ||
| slab.h | ||
| slob.c | ||
| slub.c | ||
| sparse-vmemmap.c | ||
| sparse.c | ||
| swap_state.c | ||
| swap.c | ||
| swapfile.c | ||
| truncate.c | ||
| util.c | ||
| vmalloc.c | ||
| vmscan.c | ||
| vmstat.c | ||