From ebff7d8f270d045338d9f4796014f4db429a17f9 Mon Sep 17 00:00:00 2001 From: Yasuaki Ishimatsu Date: Mon, 29 Apr 2013 15:08:56 -0700 Subject: mem hotunplug: fix kfree() of bootmem memory When hot removing memory presented at boot time, following messages are shown: kernel BUG at mm/slub.c:3409! invalid opcode: 0000 [#1] SMP Modules linked in: ebtable_nat ebtables xt_CHECKSUM iptable_mangle bridge stp llc ipmi_devintf ipmi_msghandler sunrpc ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4 iptable_filter ip_tables ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables binfmt_misc vfat fat dm_mirror dm_region_hash dm_log dm_mod vhost_net macvtap macvlan tun uinput iTCO_wdt iTCO_vendor_support coretemp kvm_intel kvm crc32c_intel ghash_clmulni_intel microcode pcspkr sg i2c_i801 lpc_ich mfd_core igb i2c_algo_bit i2c_core e1000e ptp pps_core tpm_infineon ioatdma dca sr_mod cdrom sd_mod crc_t10dif usb_storage megaraid_sas lpfc scsi_transport_fc scsi_tgt scsi_mod CPU 0 Pid: 5091, comm: kworker/0:2 Tainted: G W 3.9.0-rc6+ #15 RIP: kfree+0x232/0x240 Process kworker/0:2 (pid: 5091, threadinfo ffff88084678c000, task ffff88083928ca80) Call Trace: __release_region+0xd4/0xe0 __remove_pages+0x52/0x110 arch_remove_memory+0x89/0xd0 remove_memory+0xc4/0x100 acpi_memory_device_remove+0x6d/0xb1 acpi_device_remove+0x89/0xab __device_release_driver+0x7c/0xf0 device_release_driver+0x2f/0x50 acpi_bus_device_detach+0x6c/0x70 acpi_ns_walk_namespace+0x11a/0x250 acpi_walk_namespace+0xee/0x137 acpi_bus_trim+0x33/0x7a acpi_bus_hot_remove_device+0xc4/0x1a1 acpi_os_execute_deferred+0x27/0x34 process_one_work+0x1f7/0x590 worker_thread+0x11a/0x370 kthread+0xee/0x100 ret_from_fork+0x7c/0xb0 RIP [] kfree+0x232/0x240 RSP The reason why the messages are shown is to release a resource structure, allocated by bootmem, by kfree(). So when we release a resource structure, we should check whether it is allocated by bootmem or not. But even if we know a resource structure is allocated by bootmem, we cannot release it since SLxB cannot treat it. So for reusing a resource structure, this patch remembers it by using bootmem_resource as follows: When releasing a resource structure by free_resource(), free_resource() checks whether the resource structure is allocated by bootmem or not. If it is allocated by bootmem, free_resource() adds it to bootmem_resource. If it is not allocated by bootmem, free_resource() release it by kfree(). And when getting a new resource structure by get_resource(), get_resource() checks whether bootmem_resource has released resource structures or not. If there is a released resource structure, get_resource() returns it. If there is not a releaed resource structure, get_resource() returns new resource structure allocated by kzalloc(). [akpm@linux-foundation.org: s/get_resource/alloc_resource/] Signed-off-by: Yasuaki Ishimatsu Reviewed-by: Toshi Kani Cc: Johannes Weiner Cc: Ram Pai Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/resource.c | 68 ++++++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 55 insertions(+), 13 deletions(-) (limited to 'kernel') diff --git a/kernel/resource.c b/kernel/resource.c index 4aef8867fd4b..d7386986e10e 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -21,6 +21,7 @@ #include #include #include +#include #include @@ -50,6 +51,14 @@ struct resource_constraint { static DEFINE_RWLOCK(resource_lock); +/* + * For memory hotplug, there is no way to free resource entries allocated + * by boot mem after the system is up. So for reusing the resource entry + * we need to remember the resource. + */ +static struct resource *bootmem_resource_free; +static DEFINE_SPINLOCK(bootmem_resource_lock); + static void *r_next(struct seq_file *m, void *v, loff_t *pos) { struct resource *p = v; @@ -151,6 +160,40 @@ __initcall(ioresources_init); #endif /* CONFIG_PROC_FS */ +static void free_resource(struct resource *res) +{ + if (!res) + return; + + if (!PageSlab(virt_to_head_page(res))) { + spin_lock(&bootmem_resource_lock); + res->sibling = bootmem_resource_free; + bootmem_resource_free = res; + spin_unlock(&bootmem_resource_lock); + } else { + kfree(res); + } +} + +static struct resource *alloc_resource(gfp_t flags) +{ + struct resource *res = NULL; + + spin_lock(&bootmem_resource_lock); + if (bootmem_resource_free) { + res = bootmem_resource_free; + bootmem_resource_free = res->sibling; + } + spin_unlock(&bootmem_resource_lock); + + if (res) + memset(res, 0, sizeof(struct resource)); + else + res = kzalloc(sizeof(struct resource), flags); + + return res; +} + /* Return the conflict entry if you can't request it */ static struct resource * __request_resource(struct resource *root, struct resource *new) { @@ -771,7 +814,7 @@ static void __init __reserve_region_with_split(struct resource *root, { struct resource *parent = root; struct resource *conflict; - struct resource *res = kzalloc(sizeof(*res), GFP_ATOMIC); + struct resource *res = alloc_resource(GFP_ATOMIC); struct resource *next_res = NULL; if (!res) @@ -796,7 +839,7 @@ static void __init __reserve_region_with_split(struct resource *root, /* conflict covered whole area */ if (conflict->start <= res->start && conflict->end >= res->end) { - kfree(res); + free_resource(res); WARN_ON(next_res); break; } @@ -806,10 +849,9 @@ static void __init __reserve_region_with_split(struct resource *root, end = res->end; res->end = conflict->start - 1; if (conflict->end < end) { - next_res = kzalloc(sizeof(*next_res), - GFP_ATOMIC); + next_res = alloc_resource(GFP_ATOMIC); if (!next_res) { - kfree(res); + free_resource(res); break; } next_res->name = name; @@ -899,7 +941,7 @@ struct resource * __request_region(struct resource *parent, const char *name, int flags) { DECLARE_WAITQUEUE(wait, current); - struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL); + struct resource *res = alloc_resource(GFP_KERNEL); if (!res) return NULL; @@ -933,7 +975,7 @@ struct resource * __request_region(struct resource *parent, continue; } /* Uhhuh, that didn't work out.. */ - kfree(res); + free_resource(res); res = NULL; break; } @@ -967,7 +1009,7 @@ int __check_region(struct resource *parent, resource_size_t start, return -EBUSY; release_resource(res); - kfree(res); + free_resource(res); return 0; } EXPORT_SYMBOL(__check_region); @@ -1007,7 +1049,7 @@ void __release_region(struct resource *parent, resource_size_t start, write_unlock(&resource_lock); if (res->flags & IORESOURCE_MUXED) wake_up(&muxed_resource_wait); - kfree(res); + free_resource(res); return; } p = &res->sibling; @@ -1055,8 +1097,8 @@ int release_mem_region_adjustable(struct resource *parent, if ((start < parent->start) || (end > parent->end)) return ret; - /* The kzalloc() result gets checked later */ - new_res = kzalloc(sizeof(struct resource), GFP_KERNEL); + /* The alloc_resource() result gets checked later */ + new_res = alloc_resource(GFP_KERNEL); p = &parent->child; write_lock(&resource_lock); @@ -1083,7 +1125,7 @@ int release_mem_region_adjustable(struct resource *parent, if (res->start == start && res->end == end) { /* free the whole entry */ *p = res->sibling; - kfree(res); + free_resource(res); ret = 0; } else if (res->start == start && res->end != end) { /* adjust the start */ @@ -1119,7 +1161,7 @@ int release_mem_region_adjustable(struct resource *parent, } write_unlock(&resource_lock); - kfree(new_res); + free_resource(new_res); return ret; } #endif /* CONFIG_MEMORY_HOTREMOVE */ -- cgit v1.2.3