| Message ID | AS8PR02MB7237BA2BBAA646DFDB21C63B8B392@AS8PR02MB7237.eurprd02.prod.outlook.com (mailing list archive) |
|---|---|
| State | Deferred |
| Headers | show |
| Series | [v3] scsi: csiostor: Use kcalloc() instead of kzalloc() | expand |
On Sat, Mar 30, 2024 at 05:17:53PM +0100, Erick Archer wrote: > Use 2-factor multiplication argument form kcalloc() instead > of kzalloc(). > > Also, it is preferred to use sizeof(*pointer) instead of > sizeof(type) due to the type of the variable can change and > one needs not change the former (unlike the latter). > > Link: https://github.com/KSPP/linux/issues/162 > Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> > Signed-off-by: Erick Archer <erick.archer@outlook.com> Friendly ping. Any comments? Regards, Erick
On Sat, Mar 30, 2024 at 05:17:53PM +0100, Erick Archer wrote: > Use 2-factor multiplication argument form kcalloc() instead > of kzalloc(). > > Also, it is preferred to use sizeof(*pointer) instead of > sizeof(type) due to the type of the variable can change and > one needs not change the former (unlike the latter). > > Link: https://github.com/KSPP/linux/issues/162 > Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> > Signed-off-by: Erick Archer <erick.archer@outlook.com> > --- > Changes in v2: > - Update the changelog text describing the sizeof() > changes (Gustavo A. R. Silva) > > Changes in v3: > - Add the "Reviewed-by:" tag. > - Rebase against linux-next. > > Version 1: > Link: https://lore.kernel.org/linux-hardening/20240112182603.11048-1-erick.archer@gmx.com/ > > Version 2: > Link: https://lore.kernel.org/linux-hardening/20240114102400.3816-1-erick.archer@gmx.com/ > > Hi everyone, > > This patch seems to be lost. Gustavo reviewed it on January 15, 2024 > but the patch has not been applied since. This looks correct to me. I can pick this up if no one else snags it? Reviewed-by: Kees Cook <keescook@chromium.org> -Kees > > Thanks, > Erick > --- > drivers/scsi/csiostor/csio_init.c | 15 +++++---------- > 1 file changed, 5 insertions(+), 10 deletions(-) > > diff --git a/drivers/scsi/csiostor/csio_init.c b/drivers/scsi/csiostor/csio_init.c > index d649b7a2a879..d72892e44fd1 100644 > --- a/drivers/scsi/csiostor/csio_init.c > +++ b/drivers/scsi/csiostor/csio_init.c > @@ -698,8 +698,7 @@ csio_lnodes_block_request(struct csio_hw *hw) > struct csio_lnode **lnode_list; > int cur_cnt = 0, ii; > > - lnode_list = kzalloc((sizeof(struct csio_lnode *) * hw->num_lns), > - GFP_KERNEL); > + lnode_list = kcalloc(hw->num_lns, sizeof(*lnode_list), GFP_KERNEL); > if (!lnode_list) { > csio_err(hw, "Failed to allocate lnodes_list"); > return; > @@ -737,8 +736,7 @@ csio_lnodes_unblock_request(struct csio_hw *hw) > struct csio_lnode **lnode_list; > int cur_cnt = 0, ii; > > - lnode_list = kzalloc((sizeof(struct csio_lnode *) * hw->num_lns), > - GFP_KERNEL); > + lnode_list = kcalloc(hw->num_lns, sizeof(*lnode_list), GFP_KERNEL); > if (!lnode_list) { > csio_err(hw, "Failed to allocate lnodes_list"); > return; > @@ -775,8 +773,7 @@ csio_lnodes_block_by_port(struct csio_hw *hw, uint8_t portid) > struct csio_lnode **lnode_list; > int cur_cnt = 0, ii; > > - lnode_list = kzalloc((sizeof(struct csio_lnode *) * hw->num_lns), > - GFP_KERNEL); > + lnode_list = kcalloc(hw->num_lns, sizeof(*lnode_list), GFP_KERNEL); > if (!lnode_list) { > csio_err(hw, "Failed to allocate lnodes_list"); > return; > @@ -816,8 +813,7 @@ csio_lnodes_unblock_by_port(struct csio_hw *hw, uint8_t portid) > struct csio_lnode **lnode_list; > int cur_cnt = 0, ii; > > - lnode_list = kzalloc((sizeof(struct csio_lnode *) * hw->num_lns), > - GFP_KERNEL); > + lnode_list = kcalloc(hw->num_lns, sizeof(*lnode_list), GFP_KERNEL); > if (!lnode_list) { > csio_err(hw, "Failed to allocate lnodes_list"); > return; > @@ -855,8 +851,7 @@ csio_lnodes_exit(struct csio_hw *hw, bool npiv) > struct csio_lnode **lnode_list; > int cur_cnt = 0, ii; > > - lnode_list = kzalloc((sizeof(struct csio_lnode *) * hw->num_lns), > - GFP_KERNEL); > + lnode_list = kcalloc(hw->num_lns, sizeof(*lnode_list), GFP_KERNEL); > if (!lnode_list) { > csio_err(hw, "lnodes_exit: Failed to allocate lnodes_list.\n"); > return; > -- > 2.25.1 >
Kees, >> This patch seems to be lost. Gustavo reviewed it on January 15, 2024 >> but the patch has not been applied since. > > This looks correct to me. I can pick this up if no one else snags it? I guess my original reply didn't make it out, I don't see it in the archives. My objections were: 1. The original code is more readable to me than the proposed replacement. 2. The original code has worked since introduced in 2012. Nobody has touched it since, presumably it's fine. 3. I don't have the hardware and thus no way of validating the proposed changes. So what is the benefit of me accepting this patch? We have had several regressions in these conversions. Had one just last week, almost identical in nature to the one at hand. I am all for fixing code which is undergoing active use and development. But I really don't see the benefit of updating a legacy driver which hasn't seen updates in ages. Why risk introducing a regression?
On Mon, Apr 29, 2024 at 02:31:19PM -0400, Martin K. Petersen wrote: > > Kees, > > >> This patch seems to be lost. Gustavo reviewed it on January 15, 2024 > >> but the patch has not been applied since. > > > > This looks correct to me. I can pick this up if no one else snags it? > > I guess my original reply didn't make it out, I don't see it in the > archives. > > My objections were: > > 1. The original code is more readable to me than the proposed > replacement. I guess this is a style preference. I find the proposed easier to read. It also removes lines while doing it. :) > 2. The original code has worked since introduced in 2012. Nobody has > touched it since, presumably it's fine. The code itself is fine unless you have a 32-bit system with a malicious card, so yeah, near zero risk. > 3. I don't have the hardware and thus no way of validating the proposed > changes. This is kind of an ongoing tension we have between driver code and refactoring efforts. And this isn't a case where we can show identical binary output, since this actively adds overflow checking via kcalloc() internals. > So what is the benefit of me accepting this patch? We have had several > regressions in these conversions. Had one just last week, almost > identical in nature to the one at hand. People are working through large piles of known "weak code patterns" with the goal of reaching 0 instances in the kernel. Usually this is for ongoing greater compiler flag coverage, but this particular one is harder for the compiler to warn on, so it's from Coccinelle patterns. > I am all for fixing code which is undergoing active use and development. > But I really don't see the benefit of updating a legacy driver which > hasn't seen updates in ages. Why risk introducing a regression? I see a common pattern where "why risk introducing a regression?" gets paired with "we can't test this code". I'm really not sure what to do about this given how much the kernel is changing all the time. In this particular case, I guess all I can say is that it is a trivially correct change that uses a more robust API and more idiomatic allocation sizeof()s (i.e. use the sizeof() of what is being allocated, not a potentially disconnected struct name). -Kees
On Mon, 29 Apr 2024, Kees Cook wrote: > this isn't a case where we can show identical binary output, since this > actively adds overflow checking via kcalloc() internals. > > ... > > it is a trivially correct change that uses a more robust API and more > idiomatic allocation sizeof()s If a change is "trivially correct" then the proof is trivial too. Based only on what you wrote above, omitting the overflow check would give binary equivalence. That validates the driver change (for hardware you lack). But, since a build without the overflow check must contain a second change, you must validate that change too by showing that kcalloc() internals still work for every other caller. (You do this using hardware you have.)
diff --git a/drivers/scsi/csiostor/csio_init.c b/drivers/scsi/csiostor/csio_init.c index d649b7a2a879..d72892e44fd1 100644 --- a/drivers/scsi/csiostor/csio_init.c +++ b/drivers/scsi/csiostor/csio_init.c @@ -698,8 +698,7 @@ csio_lnodes_block_request(struct csio_hw *hw) struct csio_lnode **lnode_list; int cur_cnt = 0, ii; - lnode_list = kzalloc((sizeof(struct csio_lnode *) * hw->num_lns), - GFP_KERNEL); + lnode_list = kcalloc(hw->num_lns, sizeof(*lnode_list), GFP_KERNEL); if (!lnode_list) { csio_err(hw, "Failed to allocate lnodes_list"); return; @@ -737,8 +736,7 @@ csio_lnodes_unblock_request(struct csio_hw *hw) struct csio_lnode **lnode_list; int cur_cnt = 0, ii; - lnode_list = kzalloc((sizeof(struct csio_lnode *) * hw->num_lns), - GFP_KERNEL); + lnode_list = kcalloc(hw->num_lns, sizeof(*lnode_list), GFP_KERNEL); if (!lnode_list) { csio_err(hw, "Failed to allocate lnodes_list"); return; @@ -775,8 +773,7 @@ csio_lnodes_block_by_port(struct csio_hw *hw, uint8_t portid) struct csio_lnode **lnode_list; int cur_cnt = 0, ii; - lnode_list = kzalloc((sizeof(struct csio_lnode *) * hw->num_lns), - GFP_KERNEL); + lnode_list = kcalloc(hw->num_lns, sizeof(*lnode_list), GFP_KERNEL); if (!lnode_list) { csio_err(hw, "Failed to allocate lnodes_list"); return; @@ -816,8 +813,7 @@ csio_lnodes_unblock_by_port(struct csio_hw *hw, uint8_t portid) struct csio_lnode **lnode_list; int cur_cnt = 0, ii; - lnode_list = kzalloc((sizeof(struct csio_lnode *) * hw->num_lns), - GFP_KERNEL); + lnode_list = kcalloc(hw->num_lns, sizeof(*lnode_list), GFP_KERNEL); if (!lnode_list) { csio_err(hw, "Failed to allocate lnodes_list"); return; @@ -855,8 +851,7 @@ csio_lnodes_exit(struct csio_hw *hw, bool npiv) struct csio_lnode **lnode_list; int cur_cnt = 0, ii; - lnode_list = kzalloc((sizeof(struct csio_lnode *) * hw->num_lns), - GFP_KERNEL); + lnode_list = kcalloc(hw->num_lns, sizeof(*lnode_list), GFP_KERNEL); if (!lnode_list) { csio_err(hw, "lnodes_exit: Failed to allocate lnodes_list.\n"); return;