Re: [PATCH 1/1] Resubmit mtd: mtdoops: fix for a potential memory leak in mtdoops_notify_remove
Hi Nilanjan, On Mon, Aug 12, 2013 at 09:48:35PM -0700, Nilanjan Roychowdhury wrote: > we are allocating cxt->oops_page_used using vmalloc in mtdoops_notify_add for > every mtd_info addition but not freeing it in mtdoops_notify_remove. Also > care is > taken so that we do not free the same pointer again in module remove. > Could you re-send this with a better commit message? In particular we'd like to see why you're doing this, explaining how the current implementation implies a possible leak, explaining under what circumstance this leak. I think it would be great if you could test the patch and also add some information about the testing scenario. Please note the subject should be "[PATCH v2] mtd: ...", with a proper patch version number. The next patch will be v3 (and so on) which should be stated in the subject. Also... > Signed-off-by: Nilanjan Roychowdhury > --- In this place (between the "---" and the diffstat) you can put some changelog information, like this: Changes from v2: * Did this and that. Changes from v1: * Added check to vfree() in remove function as suggested by Ezequiel. > drivers/mtd/mtdoops.c |5 - > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c > index 97bb8f6..4b8b621 100644 > --- a/drivers/mtd/mtdoops.c > +++ b/drivers/mtd/mtdoops.c > @@ -386,6 +386,8 @@ static void mtdoops_notify_remove(struct mtd_info *mtd) > cxt->mtd = NULL; > flush_work(>work_erase); > flush_work(>work_write); > + vfree(cxt->oops_page_used); > + cxt->oops_page_used = NULL; > } > > > @@ -439,7 +441,8 @@ static void __exit mtdoops_exit(void) > > unregister_mtd_user(_notifier); > vfree(cxt->oops_buf); > - vfree(cxt->oops_page_used); > + if (cxt->oops_page_used) > + vfree(cxt->oops_page_used); > } > > > -- > 1.7.9.5 > Thanks! -- Ezequiel García, Free Electrons Embedded Linux, Kernel and Android Engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 1/1] Resubmit mtd: mtdoops: fix for a potential memory leak in mtdoops_notify_remove
Hi Nilanjan, On Mon, Aug 12, 2013 at 09:48:35PM -0700, Nilanjan Roychowdhury wrote: we are allocating cxt-oops_page_used using vmalloc in mtdoops_notify_add for every mtd_info addition but not freeing it in mtdoops_notify_remove. Also care is taken so that we do not free the same pointer again in module remove. Could you re-send this with a better commit message? In particular we'd like to see why you're doing this, explaining how the current implementation implies a possible leak, explaining under what circumstance this leak. I think it would be great if you could test the patch and also add some information about the testing scenario. Please note the subject should be [PATCH v2] mtd: ..., with a proper patch version number. The next patch will be v3 (and so on) which should be stated in the subject. Also... Signed-off-by: Nilanjan Roychowdhury nilanjan.roychowdh...@gmail.com --- In this place (between the --- and the diffstat) you can put some changelog information, like this: Changes from v2: * Did this and that. Changes from v1: * Added check to vfree() in remove function as suggested by Ezequiel. drivers/mtd/mtdoops.c |5 - 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c index 97bb8f6..4b8b621 100644 --- a/drivers/mtd/mtdoops.c +++ b/drivers/mtd/mtdoops.c @@ -386,6 +386,8 @@ static void mtdoops_notify_remove(struct mtd_info *mtd) cxt-mtd = NULL; flush_work(cxt-work_erase); flush_work(cxt-work_write); + vfree(cxt-oops_page_used); + cxt-oops_page_used = NULL; } @@ -439,7 +441,8 @@ static void __exit mtdoops_exit(void) unregister_mtd_user(mtdoops_notifier); vfree(cxt-oops_buf); - vfree(cxt-oops_page_used); + if (cxt-oops_page_used) + vfree(cxt-oops_page_used); } -- 1.7.9.5 Thanks! -- Ezequiel García, Free Electrons Embedded Linux, Kernel and Android Engineering http://free-electrons.com -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH 1/1] Resubmit mtd: mtdoops: fix for a potential memory leak in mtdoops_notify_remove
we are allocating cxt->oops_page_used using vmalloc in mtdoops_notify_add for every mtd_info addition but not freeing it in mtdoops_notify_remove. Also care is taken so that we do not free the same pointer again in module remove. Signed-off-by: Nilanjan Roychowdhury --- drivers/mtd/mtdoops.c |5 - 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c index 97bb8f6..4b8b621 100644 --- a/drivers/mtd/mtdoops.c +++ b/drivers/mtd/mtdoops.c @@ -386,6 +386,8 @@ static void mtdoops_notify_remove(struct mtd_info *mtd) cxt->mtd = NULL; flush_work(>work_erase); flush_work(>work_write); + vfree(cxt->oops_page_used); + cxt->oops_page_used = NULL; } @@ -439,7 +441,8 @@ static void __exit mtdoops_exit(void) unregister_mtd_user(_notifier); vfree(cxt->oops_buf); - vfree(cxt->oops_page_used); + if (cxt->oops_page_used) + vfree(cxt->oops_page_used); } -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH 1/1] Resubmit mtd: mtdoops: fix for a potential memory leak in mtdoops_notify_remove
we are allocating cxt-oops_page_used using vmalloc in mtdoops_notify_add for every mtd_info addition but not freeing it in mtdoops_notify_remove. Also care is taken so that we do not free the same pointer again in module remove. Signed-off-by: Nilanjan Roychowdhury nilanjan.roychowdh...@gmail.com --- drivers/mtd/mtdoops.c |5 - 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c index 97bb8f6..4b8b621 100644 --- a/drivers/mtd/mtdoops.c +++ b/drivers/mtd/mtdoops.c @@ -386,6 +386,8 @@ static void mtdoops_notify_remove(struct mtd_info *mtd) cxt-mtd = NULL; flush_work(cxt-work_erase); flush_work(cxt-work_write); + vfree(cxt-oops_page_used); + cxt-oops_page_used = NULL; } @@ -439,7 +441,8 @@ static void __exit mtdoops_exit(void) unregister_mtd_user(mtdoops_notifier); vfree(cxt-oops_buf); - vfree(cxt-oops_page_used); + if (cxt-oops_page_used) + vfree(cxt-oops_page_used); } -- 1.7.9.5 -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
