Re: [PATCH v3] zram: fix invalid memory references during disk write
On Thu, Nov 29, 2012 at 6:13 PM, Greg KH wrote: > On Fri, Nov 30, 2012 at 09:36:09AM +0900, Minchan Kim wrote: >> Hi Greg, >> >> I would like to tidy zram_bvec_write up but it needs more churn >> than needed to fix this bug and makes review hard. So I want you to pick up >> this patch asap because it's a candidate of stable. > > Ok, I have way too many different, and competing, zram patches in my > inbox right now. > > So I'm just going to delete them all, and ask Nitin to resend them all > so I know what is going on here. > > Nitin, is that ok? > Sure. I will also include affected stable version in the changelog (or whatever stable_kernel_rules says). Thanks, Nitin -- 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 v3] zram: fix invalid memory references during disk write
On Fri, Nov 30, 2012 at 09:36:09AM +0900, Minchan Kim wrote: > Hi Greg, > > I would like to tidy zram_bvec_write up but it needs more churn > than needed to fix this bug and makes review hard. So I want you to pick up > this patch asap because it's a candidate of stable. Ok, I have way too many different, and competing, zram patches in my inbox right now. So I'm just going to delete them all, and ask Nitin to resend them all so I know what is going on here. Nitin, is that ok? thanks, greg k-h -- 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 v3] zram: fix invalid memory references during disk write
On Fri, Nov 30, 2012 at 09:36:09AM +0900, Minchan Kim wrote: > Hi Greg, > > I would like to tidy zram_bvec_write up but it needs more churn > than needed to fix this bug and makes review hard. So I want you to pick up > this patch asap because it's a candidate of stable. It is? How come no one said that in the patch itself? Please read Documentation/stable_kernel_rules.txt for how to properly include a patch into the stable tree. What stable trees should it go to? thanks, greg k-h -- 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 v3] zram: fix invalid memory references during disk write
Hi Greg, I would like to tidy zram_bvec_write up but it needs more churn than needed to fix this bug and makes review hard. So I want you to pick up this patch asap because it's a candidate of stable. Thanks. On Thu, Nov 29, 2012 at 01:18:48AM -0800, Nitin Gupta wrote: > Changelog v3 vs v2: > - Further changes to changelog message to explain the bug case > of incorrect use of kunmapped buffer > Changelog v2 vs v1: > - Changelog message now correctly explains the problem > > Fixes a bug introduced by commit c8f2f0db1 ("zram: Fix handling > of incompressible pages") which caused invalid memory references > during disk write. Invalid references could occur in two cases: > - Incoming data expands on compression: In this case, reference was > made to kunmap()'ed bio page. > - Partial (non PAGE_SIZE) write with incompressible data: In this > case, reference was made to a kfree()'ed buffer. > > Fixes bug 50081: > https://bugzilla.kernel.org/show_bug.cgi?id=50081 > > Signed-off-by: Nitin Gupta > Reported-by: Mihail Kasadjikov > Reported-by: Tomas M > Reviewed-by: Minchan Kim > --- > drivers/staging/zram/zram_drv.c | 39 > --- > 1 file changed, 24 insertions(+), 15 deletions(-) > > diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c > index fb4a7c9..f2a73bd 100644 > --- a/drivers/staging/zram/zram_drv.c > +++ b/drivers/staging/zram/zram_drv.c > @@ -265,7 +265,7 @@ out_cleanup: > static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 > index, > int offset) > { > - int ret; > + int ret = 0; > size_t clen; > unsigned long handle; > struct page *page; > @@ -286,10 +286,8 @@ static int zram_bvec_write(struct zram *zram, struct > bio_vec *bvec, u32 index, > goto out; > } > ret = zram_decompress_page(zram, uncmem, index); > - if (ret) { > - kfree(uncmem); > + if (ret) > goto out; > - } > } > > /* > @@ -302,16 +300,18 @@ static int zram_bvec_write(struct zram *zram, struct > bio_vec *bvec, u32 index, > > user_mem = kmap_atomic(page); > > - if (is_partial_io(bvec)) > + if (is_partial_io(bvec)) { > memcpy(uncmem + offset, user_mem + bvec->bv_offset, > bvec->bv_len); > - else > + kunmap_atomic(user_mem); > + user_mem = NULL; > + } else { > uncmem = user_mem; > + } > > if (page_zero_filled(uncmem)) { > - kunmap_atomic(user_mem); > - if (is_partial_io(bvec)) > - kfree(uncmem); > + if (!is_partial_io(bvec)) > + kunmap_atomic(user_mem); > zram_stat_inc(>stats.pages_zero); > zram_set_flag(zram, index, ZRAM_ZERO); > ret = 0; > @@ -321,9 +321,11 @@ static int zram_bvec_write(struct zram *zram, struct > bio_vec *bvec, u32 index, > ret = lzo1x_1_compress(uncmem, PAGE_SIZE, src, , > zram->compress_workmem); > > - kunmap_atomic(user_mem); > - if (is_partial_io(bvec)) > - kfree(uncmem); > + if (!is_partial_io(bvec)) { > + kunmap_atomic(user_mem); > + user_mem = NULL; > + uncmem = NULL; > + } > > if (unlikely(ret != LZO_E_OK)) { > pr_err("Compression failed! err=%d\n", ret); > @@ -332,8 +334,10 @@ static int zram_bvec_write(struct zram *zram, struct > bio_vec *bvec, u32 index, > > if (unlikely(clen > max_zpage_size)) { > zram_stat_inc(>stats.bad_compress); > - src = uncmem; > clen = PAGE_SIZE; > + src = NULL; > + if (is_partial_io(bvec)) > + src = uncmem; > } > > handle = zs_malloc(zram->mem_pool, clen); > @@ -345,7 +349,11 @@ static int zram_bvec_write(struct zram *zram, struct > bio_vec *bvec, u32 index, > } > cmem = zs_map_object(zram->mem_pool, handle, ZS_MM_WO); > > + if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) > + src = kmap_atomic(page); > memcpy(cmem, src, clen); > + if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) > + kunmap_atomic(src); > > zs_unmap_object(zram->mem_pool, handle); > > @@ -358,9 +366,10 @@ static int zram_bvec_write(struct zram *zram, struct > bio_vec *bvec, u32 index, > if (clen <= PAGE_SIZE / 2) > zram_stat_inc(>stats.good_compress); > > - return 0; > - > out: > + if (is_partial_io(bvec)) > + kfree(uncmem); > + > if (ret) > zram_stat64_inc(zram, >stats.failed_writes); > return ret; > -- > 1.7.10.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majord...@vger.kernel.org >
Re: [PATCH v3] zram: fix invalid memory references during disk write
Hi Greg, I would like to tidy zram_bvec_write up but it needs more churn than needed to fix this bug and makes review hard. So I want you to pick up this patch asap because it's a candidate of stable. Thanks. On Thu, Nov 29, 2012 at 01:18:48AM -0800, Nitin Gupta wrote: Changelog v3 vs v2: - Further changes to changelog message to explain the bug case of incorrect use of kunmapped buffer Changelog v2 vs v1: - Changelog message now correctly explains the problem Fixes a bug introduced by commit c8f2f0db1 (zram: Fix handling of incompressible pages) which caused invalid memory references during disk write. Invalid references could occur in two cases: - Incoming data expands on compression: In this case, reference was made to kunmap()'ed bio page. - Partial (non PAGE_SIZE) write with incompressible data: In this case, reference was made to a kfree()'ed buffer. Fixes bug 50081: https://bugzilla.kernel.org/show_bug.cgi?id=50081 Signed-off-by: Nitin Gupta ngu...@vflare.org Reported-by: Mihail Kasadjikov hamer...@gmail.com Reported-by: Tomas M to...@slax.org Reviewed-by: Minchan Kim minc...@kernel.org --- drivers/staging/zram/zram_drv.c | 39 --- 1 file changed, 24 insertions(+), 15 deletions(-) diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c index fb4a7c9..f2a73bd 100644 --- a/drivers/staging/zram/zram_drv.c +++ b/drivers/staging/zram/zram_drv.c @@ -265,7 +265,7 @@ out_cleanup: static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, int offset) { - int ret; + int ret = 0; size_t clen; unsigned long handle; struct page *page; @@ -286,10 +286,8 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, goto out; } ret = zram_decompress_page(zram, uncmem, index); - if (ret) { - kfree(uncmem); + if (ret) goto out; - } } /* @@ -302,16 +300,18 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, user_mem = kmap_atomic(page); - if (is_partial_io(bvec)) + if (is_partial_io(bvec)) { memcpy(uncmem + offset, user_mem + bvec-bv_offset, bvec-bv_len); - else + kunmap_atomic(user_mem); + user_mem = NULL; + } else { uncmem = user_mem; + } if (page_zero_filled(uncmem)) { - kunmap_atomic(user_mem); - if (is_partial_io(bvec)) - kfree(uncmem); + if (!is_partial_io(bvec)) + kunmap_atomic(user_mem); zram_stat_inc(zram-stats.pages_zero); zram_set_flag(zram, index, ZRAM_ZERO); ret = 0; @@ -321,9 +321,11 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, ret = lzo1x_1_compress(uncmem, PAGE_SIZE, src, clen, zram-compress_workmem); - kunmap_atomic(user_mem); - if (is_partial_io(bvec)) - kfree(uncmem); + if (!is_partial_io(bvec)) { + kunmap_atomic(user_mem); + user_mem = NULL; + uncmem = NULL; + } if (unlikely(ret != LZO_E_OK)) { pr_err(Compression failed! err=%d\n, ret); @@ -332,8 +334,10 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, if (unlikely(clen max_zpage_size)) { zram_stat_inc(zram-stats.bad_compress); - src = uncmem; clen = PAGE_SIZE; + src = NULL; + if (is_partial_io(bvec)) + src = uncmem; } handle = zs_malloc(zram-mem_pool, clen); @@ -345,7 +349,11 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, } cmem = zs_map_object(zram-mem_pool, handle, ZS_MM_WO); + if ((clen == PAGE_SIZE) !is_partial_io(bvec)) + src = kmap_atomic(page); memcpy(cmem, src, clen); + if ((clen == PAGE_SIZE) !is_partial_io(bvec)) + kunmap_atomic(src); zs_unmap_object(zram-mem_pool, handle); @@ -358,9 +366,10 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, if (clen = PAGE_SIZE / 2) zram_stat_inc(zram-stats.good_compress); - return 0; - out: + if (is_partial_io(bvec)) + kfree(uncmem); + if (ret) zram_stat64_inc(zram, zram-stats.failed_writes); return ret; -- 1.7.10.4 -- 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
Re: [PATCH v3] zram: fix invalid memory references during disk write
On Fri, Nov 30, 2012 at 09:36:09AM +0900, Minchan Kim wrote: Hi Greg, I would like to tidy zram_bvec_write up but it needs more churn than needed to fix this bug and makes review hard. So I want you to pick up this patch asap because it's a candidate of stable. It is? How come no one said that in the patch itself? Please read Documentation/stable_kernel_rules.txt for how to properly include a patch into the stable tree. What stable trees should it go to? thanks, greg k-h -- 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 v3] zram: fix invalid memory references during disk write
On Fri, Nov 30, 2012 at 09:36:09AM +0900, Minchan Kim wrote: Hi Greg, I would like to tidy zram_bvec_write up but it needs more churn than needed to fix this bug and makes review hard. So I want you to pick up this patch asap because it's a candidate of stable. Ok, I have way too many different, and competing, zram patches in my inbox right now. So I'm just going to delete them all, and ask Nitin to resend them all so I know what is going on here. Nitin, is that ok? thanks, greg k-h -- 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 v3] zram: fix invalid memory references during disk write
On Thu, Nov 29, 2012 at 6:13 PM, Greg KH g...@kroah.com wrote: On Fri, Nov 30, 2012 at 09:36:09AM +0900, Minchan Kim wrote: Hi Greg, I would like to tidy zram_bvec_write up but it needs more churn than needed to fix this bug and makes review hard. So I want you to pick up this patch asap because it's a candidate of stable. Ok, I have way too many different, and competing, zram patches in my inbox right now. So I'm just going to delete them all, and ask Nitin to resend them all so I know what is going on here. Nitin, is that ok? Sure. I will also include affected stable version in the changelog (or whatever stable_kernel_rules says). Thanks, Nitin -- 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/