| Message ID | 1545033396-24485-2-git-send-email-frowand.list@gmail.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | of: phandle_cache, fix refcounts, remove stale entry | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | next/apply_patch Successfully applied |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 107 lines checked |
Hi Frank, frowand.list@gmail.com writes: > From: Frank Rowand <frank.rowand@sony.com> > > The phandle cache contains struct device_node pointers. The refcount > of the pointers was not incremented while in the cache, allowing use > after free error after kfree() of the node. Add the proper increment > and decrement of the use count. > > Fixes: 0b3ce78e90fc ("of: cache phandle nodes to reduce cost of of_find_node_by_phandle()") Can we also add: Cc: stable@vger.kernel.org # v4.17+ This and the next patch solve WARN_ONs and other problems for us on some systems so I think they meet the criteria for a stable backport. Rest of the patch LGTM, I'm not able to test it unfortunately, I have to defer to mwb for that. cheers > diff --git a/drivers/of/base.c b/drivers/of/base.c > index 09692c9b32a7..6c33d63361b8 100644 > --- a/drivers/of/base.c > +++ b/drivers/of/base.c > @@ -116,9 +116,6 @@ int __weak of_node_to_nid(struct device_node *np) > } > #endif > > -static struct device_node **phandle_cache; > -static u32 phandle_cache_mask; > - > /* > * Assumptions behind phandle_cache implementation: > * - phandle property values are in a contiguous range of 1..n > @@ -127,6 +124,44 @@ int __weak of_node_to_nid(struct device_node *np) > * - the phandle lookup overhead reduction provided by the cache > * will likely be less > */ > + > +static struct device_node **phandle_cache; > +static u32 phandle_cache_mask; > + > +/* > + * Caller must hold devtree_lock. > + */ > +static void __of_free_phandle_cache(void) > +{ > + u32 cache_entries = phandle_cache_mask + 1; > + u32 k; > + > + if (!phandle_cache) > + return; > + > + for (k = 0; k < cache_entries; k++) > + of_node_put(phandle_cache[k]); > + > + kfree(phandle_cache); > + phandle_cache = NULL; > +} > + > +int of_free_phandle_cache(void) > +{ > + unsigned long flags; > + > + raw_spin_lock_irqsave(&devtree_lock, flags); > + > + __of_free_phandle_cache(); > + > + raw_spin_unlock_irqrestore(&devtree_lock, flags); > + > + return 0; > +} > +#if !defined(CONFIG_MODULES) > +late_initcall_sync(of_free_phandle_cache); > +#endif > + > void of_populate_phandle_cache(void) > { > unsigned long flags; > @@ -136,8 +171,7 @@ void of_populate_phandle_cache(void) > > raw_spin_lock_irqsave(&devtree_lock, flags); > > - kfree(phandle_cache); > - phandle_cache = NULL; > + __of_free_phandle_cache(); > > for_each_of_allnodes(np) > if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL) > @@ -155,30 +189,15 @@ void of_populate_phandle_cache(void) > goto out; > > for_each_of_allnodes(np) > - if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL) > + if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL) { > + of_node_get(np); > phandle_cache[np->phandle & phandle_cache_mask] = np; > + } > > out: > raw_spin_unlock_irqrestore(&devtree_lock, flags); > } > > -int of_free_phandle_cache(void) > -{ > - unsigned long flags; > - > - raw_spin_lock_irqsave(&devtree_lock, flags); > - > - kfree(phandle_cache); > - phandle_cache = NULL; > - > - raw_spin_unlock_irqrestore(&devtree_lock, flags); > - > - return 0; > -} > -#if !defined(CONFIG_MODULES) > -late_initcall_sync(of_free_phandle_cache); > -#endif > - > void __init of_core_init(void) > { > struct device_node *np; > @@ -1195,8 +1214,11 @@ struct device_node *of_find_node_by_phandle(phandle handle) > if (!np) { > for_each_of_allnodes(np) > if (np->phandle == handle) { > - if (phandle_cache) > + if (phandle_cache) { > + /* will put when removed from cache */ > + of_node_get(np); > phandle_cache[masked_handle] = np; > + } > break; > } > } > -- > Frank Rowand <frank.rowand@sony.com>
diff --git a/drivers/of/base.c b/drivers/of/base.c index 09692c9b32a7..6c33d63361b8 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -116,9 +116,6 @@ int __weak of_node_to_nid(struct device_node *np) } #endif -static struct device_node **phandle_cache; -static u32 phandle_cache_mask; - /* * Assumptions behind phandle_cache implementation: * - phandle property values are in a contiguous range of 1..n @@ -127,6 +124,44 @@ int __weak of_node_to_nid(struct device_node *np) * - the phandle lookup overhead reduction provided by the cache * will likely be less */ + +static struct device_node **phandle_cache; +static u32 phandle_cache_mask; + +/* + * Caller must hold devtree_lock. + */ +static void __of_free_phandle_cache(void) +{ + u32 cache_entries = phandle_cache_mask + 1; + u32 k; + + if (!phandle_cache) + return; + + for (k = 0; k < cache_entries; k++) + of_node_put(phandle_cache[k]); + + kfree(phandle_cache); + phandle_cache = NULL; +} + +int of_free_phandle_cache(void) +{ + unsigned long flags; + + raw_spin_lock_irqsave(&devtree_lock, flags); + + __of_free_phandle_cache(); + + raw_spin_unlock_irqrestore(&devtree_lock, flags); + + return 0; +} +#if !defined(CONFIG_MODULES) +late_initcall_sync(of_free_phandle_cache); +#endif + void of_populate_phandle_cache(void) { unsigned long flags; @@ -136,8 +171,7 @@ void of_populate_phandle_cache(void) raw_spin_lock_irqsave(&devtree_lock, flags); - kfree(phandle_cache); - phandle_cache = NULL; + __of_free_phandle_cache(); for_each_of_allnodes(np) if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL) @@ -155,30 +189,15 @@ void of_populate_phandle_cache(void) goto out; for_each_of_allnodes(np) - if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL) + if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL) { + of_node_get(np); phandle_cache[np->phandle & phandle_cache_mask] = np; + } out: raw_spin_unlock_irqrestore(&devtree_lock, flags); } -int of_free_phandle_cache(void) -{ - unsigned long flags; - - raw_spin_lock_irqsave(&devtree_lock, flags); - - kfree(phandle_cache); - phandle_cache = NULL; - - raw_spin_unlock_irqrestore(&devtree_lock, flags); - - return 0; -} -#if !defined(CONFIG_MODULES) -late_initcall_sync(of_free_phandle_cache); -#endif - void __init of_core_init(void) { struct device_node *np; @@ -1195,8 +1214,11 @@ struct device_node *of_find_node_by_phandle(phandle handle) if (!np) { for_each_of_allnodes(np) if (np->phandle == handle) { - if (phandle_cache) + if (phandle_cache) { + /* will put when removed from cache */ + of_node_get(np); phandle_cache[masked_handle] = np; + } break; } }