| Message ID | e846103b117cc36798b1f352ed526d600fd88e16.1250132460.git.michael@ellerman.id.au (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Commit | 4f4d35667e75f81a3afb75141e732e4568e16deb |
| Delegated to: | Benjamin Herrenschmidt |
| Headers | show |
On Thu, 2009-08-13 at 13:01 +1000, Michael Ellerman wrote: > We don't actually want kmemleak to track the lmb allocations, so we > pass min_count as 0. However telling kmemleak about lmb allocations > allows it to scan that memory for pointers to other memory that is > tracked by kmemleak, ie. slab allocations etc. Looks alright to me (though I haven't tested it). You can add a Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
On Thu, 2009-08-13 at 16:40 +0100, Catalin Marinas wrote: > On Thu, 2009-08-13 at 13:01 +1000, Michael Ellerman wrote: > > We don't actually want kmemleak to track the lmb allocations, so we > > pass min_count as 0. However telling kmemleak about lmb allocations > > allows it to scan that memory for pointers to other memory that is > > tracked by kmemleak, ie. slab allocations etc. > > Looks alright to me (though I haven't tested it). You can add a > Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Actually, Milton pointed to me that we may not want to allow all LMB chunks to be scanned by kmemleaks, things like the DART hole that's taken out of the linear mapping for example may need to be avoided, though I'm not sure what would be the right way to do it. Cheers, Ben.
On Fri, 2009-08-14 at 17:56 +1000, Benjamin Herrenschmidt wrote: > On Thu, 2009-08-13 at 16:40 +0100, Catalin Marinas wrote: > > On Thu, 2009-08-13 at 13:01 +1000, Michael Ellerman wrote: > > > We don't actually want kmemleak to track the lmb allocations, so we > > > pass min_count as 0. However telling kmemleak about lmb allocations > > > allows it to scan that memory for pointers to other memory that is > > > tracked by kmemleak, ie. slab allocations etc. > > > > Looks alright to me (though I haven't tested it). You can add a > > Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> > > Actually, Milton pointed to me that we may not want to allow all > LMB chunks to be scanned by kmemleaks, things like the DART hole > that's taken out of the linear mapping for example may need to > be avoided, though I'm not sure what would be the right way to > do it. I suspect there are more blocks to be scanned than those that shouldn't, so maybe ignore the latter explicitly using kmemleak_ignore(). This was raised recently on x86_64 as well which has a memory hole for some aperture - http://lkml.org/lkml/2009/8/13/237.
From: Benjamin Herrenschmidt <benh@kernel.crashing.org> Date: Fri, 14 Aug 2009 17:56:40 +1000 > On Thu, 2009-08-13 at 16:40 +0100, Catalin Marinas wrote: >> On Thu, 2009-08-13 at 13:01 +1000, Michael Ellerman wrote: >> > We don't actually want kmemleak to track the lmb allocations, so we >> > pass min_count as 0. However telling kmemleak about lmb allocations >> > allows it to scan that memory for pointers to other memory that is >> > tracked by kmemleak, ie. slab allocations etc. >> >> Looks alright to me (though I haven't tested it). You can add a >> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> > > Actually, Milton pointed to me that we may not want to allow all > LMB chunks to be scanned by kmemleaks, things like the DART hole > that's taken out of the linear mapping for example may need to > be avoided, though I'm not sure what would be the right way to > do it. I think that annotating LMB for kmemleak may be more problems that it's worth. I can't think of any specific problems like the DART thing on sparc64, but I'm sure that as soon as someone starts trying to test this they'll run into one thing or another :-)
On Fri, 2009-08-14 at 12:49 -0700, David Miller wrote: > From: Benjamin Herrenschmidt <benh@kernel.crashing.org> > Date: Fri, 14 Aug 2009 17:56:40 +1000 > > > On Thu, 2009-08-13 at 16:40 +0100, Catalin Marinas wrote: > >> On Thu, 2009-08-13 at 13:01 +1000, Michael Ellerman wrote: > >> > We don't actually want kmemleak to track the lmb allocations, so we > >> > pass min_count as 0. However telling kmemleak about lmb allocations > >> > allows it to scan that memory for pointers to other memory that is > >> > tracked by kmemleak, ie. slab allocations etc. > >> > >> Looks alright to me (though I haven't tested it). You can add a > >> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> > > > > Actually, Milton pointed to me that we may not want to allow all > > LMB chunks to be scanned by kmemleaks, things like the DART hole > > that's taken out of the linear mapping for example may need to > > be avoided, though I'm not sure what would be the right way to > > do it. > > I think that annotating LMB for kmemleak may be more problems > that it's worth. BTW, are there many LMB allocations used for storing pointers to other objects? If not, it may be worth just annotating those with kmemleak_alloc() if you get false positives.
On Fri, 2009-08-14 at 22:57 +0100, Catalin Marinas wrote: > On Fri, 2009-08-14 at 12:49 -0700, David Miller wrote: > > From: Benjamin Herrenschmidt <benh@kernel.crashing.org> > > Date: Fri, 14 Aug 2009 17:56:40 +1000 > > > > > On Thu, 2009-08-13 at 16:40 +0100, Catalin Marinas wrote: > > >> On Thu, 2009-08-13 at 13:01 +1000, Michael Ellerman wrote: > > >> > We don't actually want kmemleak to track the lmb allocations, so we > > >> > pass min_count as 0. However telling kmemleak about lmb allocations > > >> > allows it to scan that memory for pointers to other memory that is > > >> > tracked by kmemleak, ie. slab allocations etc. > > >> > > >> Looks alright to me (though I haven't tested it). You can add a > > >> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> > > > > > > Actually, Milton pointed to me that we may not want to allow all > > > LMB chunks to be scanned by kmemleaks, things like the DART hole > > > that's taken out of the linear mapping for example may need to > > > be avoided, though I'm not sure what would be the right way to > > > do it. > > > > I think that annotating LMB for kmemleak may be more problems > > that it's worth. > > BTW, are there many LMB allocations used for storing pointers to other > objects? If not, it may be worth just annotating those with > kmemleak_alloc() if you get false positives. Yeah I think that's probably the safer approach. As Dave says even if there's nothing obvious, lmb is used for very early allocs which are more likely to be "special" and cause problems - and only when someone boots with kmemleak enabled. So we're better to explicitly mark things we want scanned. cheers
diff --git a/lib/lmb.c b/lib/lmb.c index e4a6482..b82779a 100644 --- a/lib/lmb.c +++ b/lib/lmb.c @@ -14,6 +14,7 @@ #include <linux/init.h> #include <linux/bitops.h> #include <linux/lmb.h> +#include <linux/kmemleak.h> #define LMB_ALLOC_ANYWHERE 0 @@ -352,8 +353,10 @@ u64 __init lmb_alloc_nid(u64 size, u64 align, int nid, u64 ret = lmb_alloc_nid_region(&mem->region[i], nid_range, size, align, nid); - if (ret != ~(u64)0) + if (ret != ~(u64)0) { + kmemleak_alloc(__va(ret), size, 0, 0); return ret; + } } return lmb_alloc(size, align); @@ -412,6 +415,8 @@ u64 __init __lmb_alloc_base(u64 size, u64 align, u64 max_addr) /* this area isn't reserved, take it */ if (lmb_add_region(&lmb.reserved, base, size) < 0) return 0; + + kmemleak_alloc(__va(base), size, 0, 0); return base; } res_base = lmb.reserved.region[j].base;
We don't actually want kmemleak to track the lmb allocations, so we pass min_count as 0. However telling kmemleak about lmb allocations allows it to scan that memory for pointers to other memory that is tracked by kmemleak, ie. slab allocations etc. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> --- lib/lmb.c | 7 ++++++- 1 files changed, 6 insertions(+), 1 deletions(-)