[PATCH] mempolicy: fix dangling reference to tmpfs superblock mpol
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From: Lee Schermerhorn on 15 Jun 2010 13:50 Against 2.6.35-rc1+ My patch to "Factor out duplicate put/frees in mpol_shared_policy_init() to a common return path"; and Dan Carpenter's fix thereto both left a dangling reference to the incoming tmpfs superblock mempolicy structure. A similar leak was introduced earlier when the nodemask was moved offstack to the scratch area despite the note in the comment block regarding the incoming ref. Move the remaining 'put of the incoming "mpol" to the common exit path to drop the reference. Signed-off-by: Lee Schermerhorn <lee.schermerhorn(a)hp.com> mm/mempolicy.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) Index: linux-2.6.35-rc2-mmotm-100611-1640/mm/mempolicy.c =================================================================== --- linux-2.6.35-rc2-mmotm-100611-1640.orig/mm/mempolicy.c +++ linux-2.6.35-rc2-mmotm-100611-1640/mm/mempolicy.c @@ -2138,7 +2138,7 @@ void mpol_shared_policy_init(struct shar NODEMASK_SCRATCH(scratch); if (!scratch) - return; + goto put_mpol; /* contextualize the tmpfs mount point mempolicy */ new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask); if (IS_ERR(new)) @@ -2147,19 +2147,20 @@ void mpol_shared_policy_init(struct shar task_lock(current); ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch); task_unlock(current); - mpol_put(mpol); /* drop our ref on sb mpol */ if (ret) - goto put_free; + goto put_new; /* Create pseudo-vma that contains just the policy */ memset(&pvma, 0, sizeof(struct vm_area_struct)); pvma.vm_end = TASK_SIZE; /* policy covers entire file */ mpol_set_shared_policy(sp, &pvma, new); /* adds ref */ -put_free: +put_new: mpol_put(new); /* drop initial ref */ free_scratch: NODEMASK_SCRATCH_FREE(scratch); +put_mpol: + mpol_put(mpol); /* drop our incoming ref on sb mpol */ } } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |