On Thu, Mar 21, 2024 at 05:55:57PM +0100, Robert Richter wrote: > Alison, > > On 20.03.24 10:46:07, Alison Schofield wrote: > > On Tue, Mar 19, 2024 at 01:00:23PM +0100, Robert Richter wrote: > > > For configurations that have the kconfig option NUMA_KEEP_MEMINFO > > > disabled, the SRAT lookup done with numa_fill_memblks() fails > > > returning NUMA_NO_MEMBLK (-1). An existing SRAT memory range cannot be > > > found for a CFMWS address range. This causes the addition of a > > > duplicate numa_memblk with a different node id and a subsequent page > > > fault and kernel crash during boot. > > > > > > numa_fill_memblks() is implemented and used in the init section only. > > > The option NUMA_KEEP_MEMINFO is only for the case when NUMA data will > > > be used outside of init. So fix the SRAT lookup by moving > > > numa_fill_memblks() out of the NUMA_KEEP_MEMINFO block to make it > > > always available in the init section. > > > > > > Note that the issue was initially introduced with [1]. But since > > > phys_to_target_node() was originally used that returned the valid node > > > 0, an additional numa_memblk was not added. Though, the node id was > > > wrong too. > > > > Hi Richard, > > > > I recall a bit of wrangling w #defines to make ARM64 and LOONGARCH build. > > I'm seeing an x86 build error today: > > > > >> arch/x86/mm/numa.c:957:12: error: redefinition of 'numa_fill_memblks' > > 957 | int __init numa_fill_memblks(u64 start, u64 end) > > > > include/linux/numa.h:40:26: note: previous definition of 'numa_fill_memblks' with type > > +'int(u64, u64)' {aka 'int(long long unsigned int, long long unsigned int)'} > > 40 | static inline int __init numa_fill_memblks(u64 start, u64 end) > > | ^~~~~~~~~~~~~~~~~ > > > > In addition to what you suggest, would something like this diff below be > > a useful safety measure to distinguish num_fill_memblks() success (rc:0) > > and possible non-existence (rc:-1). I don't think it hurts to take a > > second look using phys_to_target_node() (totall untested) > > > > diff --git a/drivers/acpi/numa/srat.c b/drivers/acpi/numa/srat.c > > index 070a52e4daa8..0c48fe32ced4 100644 > > --- a/drivers/acpi/numa/srat.c > > +++ b/drivers/acpi/numa/srat.c > > @@ -437,9 +437,16 @@ static int __init acpi_parse_cfmws(union acpi_subtable_headers *header, > > * found for any portion of the window to cover the entire > > * window. > > */ > > - if (!numa_fill_memblks(start, end)) > > + rc = numa_fill_memblks(start, end); > > + if (!rc) > > return 0; > > > > + if (rc == NUMA_NO_MEMBLK) { > > + node = phys_to_target_node(start); > > + if (node != NUMA_NO_NODE) > > + return 0; > > + } > > + > > for non-x86 the numa_add_memblk() function looks good in a way that it > is able to handle presumable overlapping regions. numa_fill_memblks() > would just fail then and numa_add_memblk() being called. For x86 we > need numa_fill_memblks() since x86 specific numa_add_memblk() cannot > handle the overlapping case. > > That said, we do not need the 2nd check. It looks to me that it > actually breaks non-x86 as the whole block may not be registered (if > it is larger than anything existing). > > For x86 the 2nd check may never happen if numa_fill_memblks() is > always enabled (which is this patch for). Hi Robert, (<-- got it right this time ;)) I wasn't thinking of x86, but rather archs that may not support numa_fill_memblks() and return NUMA_NO_MEMBLK (-1) per the #ifndef numa_fill_memblks in include/linux/numa.h In those cases, take a second look at phys_to_targe_node() before blindly adding another memblk. Is that the failure signature you reported here? I can wait and see your final patch and how the different archs will handle it. I'm worried that NUMA_NO_MEMBLK is overloaded and we need to diffentiate between archs that don't even look for a node, versus archs that look but don't find a node. --Alison > > So we should be good without your change. > > Thanks, > > -Robert > > > /* No SRAT description. Create a new node. */ > > > > --Alison > > > > > > > > [1] fd49f99c1809 ("ACPI: NUMA: Add a node and memblk for each CFMWS not in SRAT") > > > > > > Fixes: 8f1004679987 ("ACPI/NUMA: Apply SRAT proximity domain to entire CFMWS window") > > > Cc: Derick Marks <derick.w.marks@xxxxxxxxx> > > > Cc: Dan Williams <dan.j.williams@xxxxxxxxx> > > > Cc: Alison Schofield <alison.schofield@xxxxxxxxx> > > > Signed-off-by: Robert Richter <rrichter@xxxxxxx> > > > --- > > > arch/x86/mm/numa.c | 4 ++-- > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c > > > index 65e9a6e391c0..ce84ba86e69e 100644 > > > --- a/arch/x86/mm/numa.c > > > +++ b/arch/x86/mm/numa.c > > > @@ -929,6 +929,8 @@ int memory_add_physaddr_to_nid(u64 start) > > > } > > > EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid); > > > > > > +#endif > > > + > > > static int __init cmp_memblk(const void *a, const void *b) > > > { > > > const struct numa_memblk *ma = *(const struct numa_memblk **)a; > > > @@ -1001,5 +1003,3 @@ int __init numa_fill_memblks(u64 start, u64 end) > > > } > > > return 0; > > > } > > > - > > > -#endif > > > -- > > > 2.39.2 > > >