The patch titled Subject: Bug fix: Hold spinlock across find|remove /sys/firmware/memmap/X operation. has been added to the -mm tree. Its filename is memory-hotplug-remove-sys-firmware-memmap-x-sysfs-fix.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 *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Tang Chen <tangchen@xxxxxxxxxxxxxx> Subject: Bug fix: Hold spinlock across find|remove /sys/firmware/memmap/X operation. It is unsafe to return an entry pointer and release the map_entries_lock. So we should not hold the map_entries_lock separately in firmware_map_find_entry() and firmware_map_remove_entry(). Hold the map_entries_lock across find and remove /sys/firmware/memmap/X operation. And also, users of these two functions need to be careful to hold the lock when using these two functions. The suggestion is from Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Tang Chen <tangchen@xxxxxxxxxxxxxx> Cc: Wen Congyang <wency@xxxxxxxxxxxxxx> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx> Cc: Tang Chen <tangchen@xxxxxxxxxxxxxx> Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/firmware/memmap.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff -puN drivers/firmware/memmap.c~memory-hotplug-remove-sys-firmware-memmap-x-sysfs-fix drivers/firmware/memmap.c --- a/drivers/firmware/memmap.c~memory-hotplug-remove-sys-firmware-memmap-x-sysfs-fix +++ a/drivers/firmware/memmap.c @@ -150,12 +150,12 @@ static int firmware_map_add_entry(u64 st * firmware_map_remove_entry() - Does the real work to remove a firmware * memmap entry. * @entry: removed entry. + * + * The caller must hold map_entries_lock, and release it properly. **/ static inline void firmware_map_remove_entry(struct firmware_map_entry *entry) { - spin_lock(&map_entries_lock); list_del(&entry->list); - spin_unlock(&map_entries_lock); } /* @@ -188,23 +188,28 @@ static inline void remove_sysfs_fw_map_e } /* - * Search memmap entry + * firmware_map_find_entry: Search memmap entry. + * @start: Start of the memory range. + * @end: End of the memory range (exclusive). + * @type: Type of the memory range. + * + * This function is to find the memmap entey of a given memory range. + * The caller must hold map_entries_lock, and must not release the lock + * until the processing of the returned entry has completed. + * + * Return pointer to the entry to be found on success, or NULL on failure. */ - static struct firmware_map_entry * __meminit firmware_map_find_entry(u64 start, u64 end, const char *type) { struct firmware_map_entry *entry; - spin_lock(&map_entries_lock); list_for_each_entry(entry, &map_entries, list) if ((entry->start == start) && (entry->end == end) && (!strcmp(entry->type, type))) { - spin_unlock(&map_entries_lock); return entry; } - spin_unlock(&map_entries_lock); return NULL; } @@ -274,11 +279,15 @@ int __meminit firmware_map_remove(u64 st { struct firmware_map_entry *entry; + spin_lock(&map_entries_lock); entry = firmware_map_find_entry(start, end - 1, type); - if (!entry) + if (!entry) { + spin_unlock(&map_entries_lock); return -EINVAL; + } firmware_map_remove_entry(entry); + spin_unlock(&map_entries_lock); /* remove the memmap entry */ remove_sysfs_fw_map_entry(entry); _ Patches currently in -mm which might be from tangchen@xxxxxxxxxxxxxx are memory-hotplug-try-to-offline-the-memory-twice-to-avoid-dependence.patch memory-hotplug-check-whether-all-memory-blocks-are-offlined-or-not-when-removing-memory.patch memory-hotplug-remove-redundant-codes.patch memory-hotplug-remove-sys-firmware-memmap-x-sysfs.patch memory-hotplug-remove-sys-firmware-memmap-x-sysfs-fix.patch memory-hotplug-introduce-new-arch_remove_memory-for-removing-page-table.patch memory-hotplug-implement-register_page_bootmem_info_section-of-sparse-vmemmap.patch memory-hotplug-move-pgdat_resize_lock-into-sparse_remove_one_section.patch memory-hotplug-common-apis-to-support-page-tables-hot-remove.patch memory-hotplug-common-apis-to-support-page-tables-hot-remove-fix.patch memory-hotplug-remove-page-table-of-x86_64-architecture.patch memory-hotplug-remove-page-table-of-x86_64-architecture-fix.patch memory-hotplug-remove-memmap-of-sparse-vmemmap.patch memory-hotplug-integrated-__remove_section-of-config_sparsemem_vmemmap.patch memory_hotplug-clear-zone-when-removing-the-memory.patch memory-hotplug-remove-sysfs-file-of-node.patch memory-hotplug-free-node_data-when-a-node-is-offlined.patch memory-hotplug-do-not-allocate-pdgat-if-it-was-not-freed-when-offline.patch x86-get-pg_data_ts-memory-from-other-node.patch page_alloc-add-movable_memmap-kernel-parameter.patch page_alloc-add-movable_memmap-kernel-parameter-fix.patch page_alloc-introduce-zone_movable_limit-to-keep-movable-limit-for-nodes.patch page_alloc-make-movablecore_map-has-higher-priority.patch page_alloc-bootmem-limit-with-movablecore_map.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