6.6-stable review patch. If anyone has any objections, please let me know.
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From: Ritesh Harjani (IBM) ritesh.list@gmail.com
[ Upstream commit 05b94cae1c47f94588c3e7096963c1007c4d9c1d ]
During early init CMA_MIN_ALIGNMENT_BYTES can be PAGE_SIZE, since pageblock_order is still zero and it gets initialized later during initmem_init() e.g. setup_arch() -> initmem_init() -> sparse_init() -> set_pageblock_order()
One such use case where this causes issue is - early_setup() -> early_init_devtree() -> fadump_reserve_mem() -> fadump_cma_init()
This causes CMA memory alignment check to be bypassed in cma_init_reserved_mem(). Then later cma_activate_area() can hit a VM_BUG_ON_PAGE(pfn & ((1 << order) - 1)) if the reserved memory area was not pageblock_order aligned.
Fix it by moving the fadump_cma_init() after initmem_init(), where other such cma reservations also gets called.
<stack trace> ============== page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10010 flags: 0x13ffff800000000(node=1|zone=0|lastcpupid=0x7ffff) CMA raw: 013ffff800000000 5deadbeef0000100 5deadbeef0000122 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: VM_BUG_ON_PAGE(pfn & ((1 << order) - 1)) ------------[ cut here ]------------ kernel BUG at mm/page_alloc.c:778!
Call Trace: __free_one_page+0x57c/0x7b0 (unreliable) free_pcppages_bulk+0x1a8/0x2c8 free_unref_page_commit+0x3d4/0x4e4 free_unref_page+0x458/0x6d0 init_cma_reserved_pageblock+0x114/0x198 cma_init_reserved_areas+0x270/0x3e0 do_one_initcall+0x80/0x2f8 kernel_init_freeable+0x33c/0x530 kernel_init+0x34/0x26c ret_from_kernel_user_thread+0x14/0x1c
Fixes: 11ac3e87ce09 ("mm: cma: use pageblock_order as the single alignment") Suggested-by: David Hildenbrand david@redhat.com Reported-by: Sachin P Bappalige sachinpb@linux.ibm.com Acked-by: Hari Bathini hbathini@linux.ibm.com Reviewed-by: Madhavan Srinivasan maddy@linux.ibm.com Signed-off-by: Ritesh Harjani (IBM) ritesh.list@gmail.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://patch.msgid.link/3ae208e48c0d9cefe53d2dc4f593388067405b7d.1729146153... Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/include/asm/fadump.h | 7 +++++++ arch/powerpc/kernel/fadump.c | 6 +----- arch/powerpc/kernel/setup-common.c | 6 ++++-- 3 files changed, 12 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/include/asm/fadump.h b/arch/powerpc/include/asm/fadump.h index 526a6a6473128..daa44b2ef35ad 100644 --- a/arch/powerpc/include/asm/fadump.h +++ b/arch/powerpc/include/asm/fadump.h @@ -32,4 +32,11 @@ extern int early_init_dt_scan_fw_dump(unsigned long node, const char *uname, int depth, void *data); extern int fadump_reserve_mem(void); #endif + +#if defined(CONFIG_FA_DUMP) && defined(CONFIG_CMA) +void fadump_cma_init(void); +#else +static inline void fadump_cma_init(void) { } +#endif + #endif /* _ASM_POWERPC_FADUMP_H */ diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c index 4722a9e606e61..1866bac234000 100644 --- a/arch/powerpc/kernel/fadump.c +++ b/arch/powerpc/kernel/fadump.c @@ -80,7 +80,7 @@ static struct cma *fadump_cma; * But for some reason even if it fails we still have the memory reservation * with us and we can still continue doing fadump. */ -static void __init fadump_cma_init(void) +void __init fadump_cma_init(void) { unsigned long long base, size; int rc; @@ -124,8 +124,6 @@ static void __init fadump_cma_init(void) (unsigned long)cma_get_base(fadump_cma) >> 20, fw_dump.reserve_dump_area_size); } -#else -static void __init fadump_cma_init(void) { } #endif /* CONFIG_CMA */
/* Scan the Firmware Assisted dump configuration details. */ @@ -642,8 +640,6 @@ int __init fadump_reserve_mem(void)
pr_info("Reserved %lldMB of memory at %#016llx (System RAM: %lldMB)\n", (size >> 20), base, (memblock_phys_mem_size() >> 20)); - - fadump_cma_init(); }
return ret; diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c index 03eaad5949f14..d43db8150767b 100644 --- a/arch/powerpc/kernel/setup-common.c +++ b/arch/powerpc/kernel/setup-common.c @@ -988,9 +988,11 @@ void __init setup_arch(char **cmdline_p) initmem_init();
/* - * Reserve large chunks of memory for use by CMA for KVM and hugetlb. These must - * be called after initmem_init(), so that pageblock_order is initialised. + * Reserve large chunks of memory for use by CMA for fadump, KVM and + * hugetlb. These must be called after initmem_init(), so that + * pageblock_order is initialised. */ + fadump_cma_init(); kvm_cma_reserve(); gigantic_hugetlb_cma_reserve();