This is a note to let you know that I've just added the patch titled of: fix memory leak related to safe_name() to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: of-fix-memory-leak-related-to-safe_name.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From d9fc880723321dbf16b2981e3f3e916b73942210 Mon Sep 17 00:00:00 2001 From: Frank Rowand <frank.rowand@xxxxxxxxxxx> Date: Thu, 16 Jun 2016 10:51:46 -0700 Subject: of: fix memory leak related to safe_name() From: Frank Rowand <frank.rowand@xxxxxxxxxxx> commit d9fc880723321dbf16b2981e3f3e916b73942210 upstream. Fix a memory leak resulting from memory allocation in safe_name(). This patch fixes all call sites of safe_name(). Mathieu Malaterre reported the memory leak on boot: On my PowerMac device-tree would generate a duplicate name: [ 0.023043] device-tree: Duplicate name in PowerPC,G4@0, renamed to "l2-cache#1" in this case a newly allocated name is generated by `safe_name`. However in this case it is never deallocated. The bug was found using kmemleak reported as: unreferenced object 0xdf532e60 (size 32): comm "swapper", pid 1, jiffies 4294892300 (age 1993.532s) hex dump (first 32 bytes): 6c 32 2d 63 61 63 68 65 23 31 00 dd e4 dd 1e c2 l2-cache#1...... ec d4 ba ce 04 ec cc de 8e 85 e9 ca c4 ec cc 9e ................ backtrace: [<c02d3350>] kvasprintf+0x64/0xc8 [<c02d3400>] kasprintf+0x4c/0x5c [<c0453814>] safe_name.isra.1+0x80/0xc4 [<c04545d8>] __of_attach_node_sysfs+0x6c/0x11c [<c075f21c>] of_core_init+0x8c/0xf8 [<c0729594>] kernel_init_freeable+0xd4/0x208 [<c00047e8>] kernel_init+0x24/0x11c [<c00158ec>] ret_from_kernel_thread+0x5c/0x64 Link: https://bugzilla.kernel.org/show_bug.cgi?id=120331 Signed-off-by: Frank Rowand <frank.rowand@xxxxxxxxxxx> Reported-by: mathieu.malaterre@xxxxxxxxx Tested-by: Mathieu Malaterre <mathieu.malaterre@xxxxxxxxx> Signed-off-by: Rob Herring <robh@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/of/base.c | 30 +++++++++++++++++++++--------- drivers/of/dynamic.c | 2 +- drivers/of/of_private.h | 3 +++ 3 files changed, 25 insertions(+), 10 deletions(-) --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -112,6 +112,7 @@ static ssize_t of_node_property_read(str return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length); } +/* always return newly allocated name, caller must free after use */ static const char *safe_name(struct kobject *kobj, const char *orig_name) { const char *name = orig_name; @@ -126,9 +127,12 @@ static const char *safe_name(struct kobj name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i); } - if (name != orig_name) + if (name == orig_name) { + name = kstrdup(orig_name, GFP_KERNEL); + } else { pr_warn("device-tree: Duplicate name in %s, renamed to \"%s\"\n", kobject_name(kobj), name); + } return name; } @@ -159,6 +163,7 @@ int __of_add_property_sysfs(struct devic int __of_attach_node_sysfs(struct device_node *np) { const char *name; + struct kobject *parent; struct property *pp; int rc; @@ -171,15 +176,16 @@ int __of_attach_node_sysfs(struct device np->kobj.kset = of_kset; if (!np->parent) { /* Nodes without parents are new top level trees */ - rc = kobject_add(&np->kobj, NULL, "%s", - safe_name(&of_kset->kobj, "base")); + name = safe_name(&of_kset->kobj, "base"); + parent = NULL; } else { name = safe_name(&np->parent->kobj, kbasename(np->full_name)); - if (!name || !name[0]) - return -EINVAL; - - rc = kobject_add(&np->kobj, &np->parent->kobj, "%s", name); + parent = &np->parent->kobj; } + if (!name) + return -ENOMEM; + rc = kobject_add(&np->kobj, parent, "%s", name); + kfree(name); if (rc) return rc; @@ -1753,6 +1759,12 @@ int __of_remove_property(struct device_n return 0; } +void __of_sysfs_remove_bin_file(struct device_node *np, struct property *prop) +{ + sysfs_remove_bin_file(&np->kobj, &prop->attr); + kfree(prop->attr.attr.name); +} + void __of_remove_property_sysfs(struct device_node *np, struct property *prop) { if (!IS_ENABLED(CONFIG_SYSFS)) @@ -1760,7 +1772,7 @@ void __of_remove_property_sysfs(struct d /* at early boot, bail here and defer setup to of_init() */ if (of_kset && of_node_is_attached(np)) - sysfs_remove_bin_file(&np->kobj, &prop->attr); + __of_sysfs_remove_bin_file(np, prop); } /** @@ -1830,7 +1842,7 @@ void __of_update_property_sysfs(struct d return; if (oldprop) - sysfs_remove_bin_file(&np->kobj, &oldprop->attr); + __of_sysfs_remove_bin_file(np, oldprop); __of_add_property_sysfs(np, newprop); } --- a/drivers/of/dynamic.c +++ b/drivers/of/dynamic.c @@ -55,7 +55,7 @@ void __of_detach_node_sysfs(struct devic /* only remove properties if on sysfs */ if (of_node_is_attached(np)) { for_each_property_of_node(np, pp) - sysfs_remove_bin_file(&np->kobj, &pp->attr); + __of_sysfs_remove_bin_file(np, pp); kobject_del(&np->kobj); } --- a/drivers/of/of_private.h +++ b/drivers/of/of_private.h @@ -81,6 +81,9 @@ extern int __of_attach_node_sysfs(struct extern void __of_detach_node(struct device_node *np); extern void __of_detach_node_sysfs(struct device_node *np); +extern void __of_sysfs_remove_bin_file(struct device_node *np, + struct property *prop); + /* iterators for transactions, used for overlays */ /* forward iterator */ #define for_each_transaction_entry(_oft, _te) \ Patches currently in stable-queue which might be from frank.rowand@xxxxxxxxxxx are queue-4.4/of-fix-memory-leak-related-to-safe_name.patch queue-4.4/tty-serial-msm-don-t-read-off-end-of-tx-fifo.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html