Re: [PATCH v2 4/4] mm, arch: add generic implementation of pfn_valid() for FLATMEM

Mike Rapoport
2023-01-31T18:42:30Z

Hi Conor,

On Tue, Jan 31, 2023 at 05:47:24PM +0000, Conor Dooley wrote:
> Hey Mike,
>
> On Sun, Jan 29, 2023 at 02:42:35PM +0200, Mike Rapoport wrote:
> > From: "Mike Rapoport (IBM)" <rppt@kernel.org>
> >
> > Every architecture that supports FLATMEM memory model defines its own
> > version of pfn_valid() that essentially compares a pfn to max_mapnr.
> >
> > Use mips/powerpc version implemented as static inline as a generic
> > implementation of pfn_valid() and drop its per-architecture definitions.
> >
> > Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
> > Acked-by: Arnd Bergmann <arnd@arndb.de>
> > Acked-by: Guo Ren <guoren@kernel.org> # csky
> > Acked-by: Huacai Chen <chenhuacai@loongson.cn> # LoongArch
> > Acked-by: Stafford Horne <shorne@gmail.com> # OpenRISC
>
> Hmm, so this landed in linux-next today and I bisected a boot failure in
> my CI to it. However, I am not really sure if it is a real issue worth
> worrying about as the platform it triggered on is supposed to be using
> SPARSEMEM, but isn't.
> I had thought that my CI was using a config with SPARSEMEM since that
> became required for riscv defconfig builds to boot in v6.1-rc1, but I
> must have just forgotten to add it to my $platform_defconfig builds too.
> However, those $platform_defconfig builds continued booting without
> SPARSEMEM enabled until today.

The issue seems to be that the generic pfn_valid() does not take into
account pfn_offset when it compares it with max_mapnr.
Can you please test with the patch below?

diff --git a/include/asm-generic/memory_model.h b/include/asm-generic/memory_model.h
index 13d2a844d928..6796abe1900e 100644
--- a/include/asm-generic/memory_model.h
+++ b/include/asm-generic/memory_model.h
@@ -26,7 +26,7 @@ static inline int pfn_valid(unsigned long pfn)
extern unsigned long max_mapnr;
unsigned long pfn_offset = ARCH_PFN_OFFSET;

- return pfn >= pfn_offset && pfn < max_mapnr;
+ return pfn >= pfn_offset && (pfn - pfn_offset) < max_mapnr;
}
#define pfn_valid pfn_valid
#endif

> for $platform_defconfig builds I now see the following, which is in turn
> followed by an opps. The full output is at the bottom of this mail.
>
> WARNING: CPU: 0 PID: 0 at mm/vmalloc.c:479 __vmap_pages_range_noflush+0x2d4/0x4c8
> Modules linked in:
> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.2.0-rc4-00538-g6e265f6be0c8 #1
> Hardware name: Microchip PolarFire-SoC Icicle Kit (DT)
> epc : __vmap_pages_range_noflush+0x2d4/0x4c8
> ra : __vmap_pages_range_noflush+0x3e0/0x4c8
> epc : ffffffff801461e4 ra : ffffffff801462f0 sp : ffffffff81203b90
> gp : ffffffff812e9fe0 tp : ffffffff8120fa80 t0 : ffffffe7bfe57000
> t1 : ffffffffffff8000 t2 : 00000000000001a7 s0 : ffffffff81203c50
> s1 : ffffffe7bfe56040 a0 : 0000000000000000 a1 : ffffffe7c7df2840
> a2 : ffffffff812ebae8 a3 : 0000000000001000 a4 : 0000000000080200
> a5 : 0000000000fffe00 a6 : 0000000001040056 a7 : ffffffffffffffff
> s2 : 0000000001040024 s3 : ffffffff80de1118 s4 : ffffffc80400c000
> s5 : ffffffc80400c000 s6 : 00000000000000e7 s7 : 0000000000000000
> s8 : ffffffc80400bfff s9 : 00fffffffffff000 s10: ffffffc804008000
> s11: ffffffe7bfe0d100 t3 : 0000000000000000 t4 : fffffffffff00000
> t5 : 00000000000f0000 t6 : ffffffe7bfe22ac4
> status: 0000000200000120 badaddr: 0000000000000000 cause: 0000000000000003
> [<ffffffff8014762a>] __vmalloc_node_range+0x392/0x52e
> [<ffffffff8000dfc4>] copy_process+0x636/0x1196
> [<ffffffff8000ec42>] kernel_clone+0x4a/0x2f4
> [<ffffffff8000f15e>] user_mode_thread+0x7c/0x9a
> [<ffffffff8077056e>] rest_init+0x28/0xea
> [<ffffffff80800670>] arch_post_acpi_subsys_init+0x0/0x18
> [<ffffffff80800de4>] start_kernel+0x72c/0x75c
>
> In my mind, there's a kernel misconfiguration issue, but it's not the
> same splat as I used to get when using FLATMEM in this configuration:
> OF: fdt: Ignoring memory range 0x80000000 - 0x80200000
> Machine model: Microchip PolarFire-SoC Icicle Kit
> earlycon: ns16550a0 at MMIO32 0x0000000020100000 (options '115200n8')
> printk: bootconsole [ns16550a0] enabled
> printk: debug: skip boot console de-registration.
> efi: UEFI not found.
> Zone ranges:
> DMA32 [mem 0x0000000080200000-0x00000000ffffffff]
> Normal [mem 0x0000000100000000-0x000000107fffffff]
> Movable zone start for each node
> Early memory node ranges
> node 0: [mem 0x0000000080200000-0x00000000bfbfffff]
> node 0: [mem 0x00000000bfc00000-0x00000000bfffffff]
> node 0: [mem 0x0000001040000000-0x000000107fffffff]
> Initmem setup node 0 [mem 0x0000000080200000-0x000000107fffffff]
> Kernel panic - not syncing: Failed to allocate 1073741824 bytes for node 0 memory map
> CPU: 0 PID: 0 Comm: swapper Not tainted 5.19.0-dirty #1
> Hardware name: Microchip PolarFire-SoC Icicle Kit (DT)
> Call Trace:
> [<ffffffff800057f0>] show_stack+0x30/0x3c
> [<ffffffff807d5802>] dump_stack_lvl+0x4a/0x66
> [<ffffffff807d5836>] dump_stack+0x18/0x20
> [<ffffffff807d1ae8>] panic+0x124/0x2c6
> [<ffffffff80814064>] free_area_init_core+0x0/0x11e
> [<ffffffff80813720>] free_area_init_node+0xc2/0xf6
> [<ffffffff8081331e>] free_area_init+0x222/0x260
> [<ffffffff808064d6>] misc_mem_init+0x62/0x9a
> [<ffffffff80803cb2>] setup_arch+0xb0/0xea
> [<ffffffff8080039a>] start_kernel+0x88/0x4ee
>
> Turning on SPARSEMEM fixes both problems, but I'm just not sure if there
> is some underlying issue here that I don't know enough about the area to
> understand.
>
> Thanks,
> Conor.
>
> [ 0.000000] Linux version 6.2.0-rc4-00538-g6e265f6be0c8 (conor@wendy) (riscv64-unknown-linux-gnu-gcc (g5964b5cd727)
> 11.1.0, GNU ld (GNU Binutils) 2.37) #1 SMP PREEMPT @7
> [ 0.000000] OF: fdt: Ignoring memory range 0x80000000 - 0x80200000
> [ 0.000000] Machine model: Microchip PolarFire-SoC Icicle Kit
> [ 0.000000] earlycon: ns16550a0 at MMIO32 0x0000000020100000 (options '115200n8')
> [ 0.000000] printk: bootconsole [ns16550a0] enabled
> [ 0.000000] printk: debug: skip boot console de-registration.
> [ 0.000000] efi: UEFI not found.
> [ 0.000000] Zone ranges:
> [ 0.000000] DMA32 [mem 0x0000000080200000-0x00000000ffffffff]
> [ 0.000000] Normal [mem 0x0000000100000000-0x000000107fffffff]
> [ 0.000000] Movable zone start for each node
> [ 0.000000] Early memory node ranges
> [ 0.000000] node 0: [mem 0x0000000080200000-0x00000000bfbfffff]
> [ 0.000000] node 0: [mem 0x00000000bfc00000-0x00000000bfffffff]
> [ 0.000000] node 0: [mem 0x0000001040000000-0x000000107fffffff]
> [ 0.000000] Initmem setup node 0 [mem 0x0000000080200000-0x000000107fffffff]
> [ 0.000000] On node 0, zone Normal: 15990272 pages in unavailable ranges
> [ 0.000000] SBI specification v0.3 detected
> [ 0.000000] SBI implementation ID=0x1 Version=0x10000
> [ 0.000000] SBI TIME extension detected
> [ 0.000000] SBI IPI extension detected
> [ 0.000000] SBI RFENCE extension detected
> [ 0.000000] SBI SRST extension detected
> [ 0.000000] SBI HSM extension detected
> [ 0.000000] CPU with hartid=0 is not available
> [ 0.000000] CPU with hartid=0 is not available
> [ 0.000000] CPU with hartid=0 is not available
> [ 0.000000] riscv: base ISA extensions acdfim
> [ 0.000000] riscv: ELF capabilities acdfim
> [ 0.000000] percpu: Embedded 19 pages/cpu s37048 r8192 d32584 u77824
> [ 0.000000] CPU node for /cpus/cpu@0 exist but the possible cpu range is :0-3
> [ 0.000000] Built 1 zonelists, mobility grouping on. Total pages: 294407
> [ 0.000000] Kernel command line: earlycon keep_bootcon reboot=cold
> [ 0.000000] Dentry cache hash table entries: 262144 (order: 9, 2097152 bytes, linear)
> [ 0.000000] Inode-cache hash table entries: 131072 (order: 8, 1048576 bytes, linear)
> [ 0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off
> [ 0.000000] software IO TLB: area num 4.
> [ 0.000000] software IO TLB: mapped [mem 0x00000000bbc00000-0x00000000bfc00000] (64MB)
> [ 0.000000] Virtual kernel memory layout:
> [ 0.000000] fixmap : 0xffffffc6fee00000 - 0xffffffc6ff000000 (2048 kB)
> [ 0.000000] pci io : 0xffffffc6ff000000 - 0xffffffc700000000 ( 16 MB)
> [ 0.000000] vmemmap : 0xffffffc700000000 - 0xffffffc800000000 (4096 MB)
> [ 0.000000] vmalloc : 0xffffffc800000000 - 0xffffffd800000000 ( 64 GB)
> [ 0.000000] modules : 0xffffffff01352000 - 0xffffffff80000000 (2028 MB)
> [ 0.000000] lowmem : 0xffffffd800000000 - 0xffffffe7ffe00000 ( 63 GB)
> [ 0.000000] kernel : 0xffffffff80000000 - 0xffffffffffffffff (2047 MB)
> [ 0.000000] Memory: 1067600K/2095104K available (7639K kernel code, 4898K rwdata, 4096K rodata, 2183K init, 410K bss, 1027504K reserved, 0K cma-reserved)
> [ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
> [ 0.000000] rcu: Preemptible hierarchical RCU implementation.
> [ 0.000000] rcu: RCU restricting CPUs from NR_CPUS=64 to nr_cpu_ids=4.
> [ 0.000000] rcu: RCU debug extended QS entry/exit.
> [ 0.000000] Trampoline variant of Tasks RCU enabled.
> [ 0.000000] Tracing variant of Tasks RCU enabled.
> [ 0.000000] rcu: RCU calculated value of scheduler-enlistment delay is 25 jiffies.
> [ 0.000000] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=4
> [ 0.000000] NR_IRQS: 64, nr_irqs: 64, preallocated irqs: 0
> [ 0.000000] CPU with hartid=0 is not available
> [ 0.000000] riscv-intc: unable to find hart id for /cpus/cpu@0/interrupt-controller
> [ 0.000000] riscv-intc: 64 local interrupts mapped
> [ 0.000000] plic: interrupt-controller@c000000: mapped 186 interrupts with 4 handlers for 9 contexts.
> [ 0.000000] rcu: srcu_init: Setting srcu_struct sizes based on contention.
> [ 0.000000] riscv-timer: riscv_timer_init_dt: Registering clocksource cpuid [0] hartid [1]
> [ 0.000000] clocksource: riscv_clocksource: mask: 0xffffffffffffffff max_cycles: 0x1d854df40, max_idle_ns: 3526361616960 ns
> [ 0.000004] sched_clock: 64 bits at 1000kHz, resolution 1000ns, wraps every 2199023255500ns
> [ 0.009687] Console: colour dummy device 80x25
> [ 0.014654] printk: console [tty0] enabled
> [ 0.019313] Calibrating delay loop (skipped), value calculated using timer frequency.. 2.00 BogoMIPS (lpj=4000)
> [ 0.030490] pid_max: default: 32768 minimum: 301
> [ 0.036094] Mount-cache hash table entries: 4096 (order: 3, 32768 bytes, linear)
> [ 0.044458] Mountpoint-cache hash table entries: 4096 (order: 3, 32768 bytes, linear)
> [ 0.055493] ------------[ cut here ]------------
> [ 0.060606] WARNING: CPU: 0 PID: 0 at mm/vmalloc.c:479 __vmap_pages_range_noflush+0x2d4/0x4c8
> [ 0.070040] Modules linked in:
> [ 0.073421] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.2.0-rc4-00538-g6e265f6be0c8 #1
> [ 0.082157] Hardware name: Microchip PolarFire-SoC Icicle Kit (DT)
> [ 0.088972] epc : __vmap_pages_range_noflush+0x2d4/0x4c8
> [ 0.094838] ra : __vmap_pages_range_noflush+0x3e0/0x4c8
> [ 0.100707] epc : ffffffff801461e4 ra : ffffffff801462f0 sp : ffffffff81203b90
> [ 0.108674] gp : ffffffff812e9fe0 tp : ffffffff8120fa80 t0 : ffffffe7bfe57000
> [ 0.116643] t1 : ffffffffffff8000 t2 : 00000000000001a7 s0 : ffffffff81203c50
> [ 0.124611] s1 : ffffffe7bfe56040 a0 : 0000000000000000 a1 : ffffffe7c7df2840
> [ 0.132588] a2 : ffffffff812ebae8 a3 : 0000000000001000 a4 : 0000000000080200
> [ 0.140564] a5 : 0000000000fffe00 a6 : 0000000001040056 a7 : ffffffffffffffff
> [ 0.148541] s2 : 0000000001040024 s3 : ffffffff80de1118 s4 : ffffffc80400c000
> [ 0.156518] s5 : ffffffc80400c000 s6 : 00000000000000e7 s7 : 0000000000000000
> [ 0.164495] s8 : ffffffc80400bfff s9 : 00fffffffffff000 s10: ffffffc804008000
> [ 0.172472] s11: ffffffe7bfe0d100 t3 : 0000000000000000 t4 : fffffffffff00000
> [ 0.180449] t5 : 00000000000f0000 t6 : ffffffe7bfe22ac4
> [ 0.186317] status: 0000000200000120 badaddr: 0000000000000000 cause: 0000000000000003
> [ 0.195060] [<ffffffff8014762a>] __vmalloc_node_range+0x392/0x52e
> [ 0.201802] [<ffffffff8000dfc4>] copy_process+0x636/0x1196
> [ 0.207878] [<ffffffff8000ec42>] kernel_clone+0x4a/0x2f4
> [ 0.213755] [<ffffffff8000f15e>] user_mode_thread+0x7c/0x9a
> [ 0.219918] [<ffffffff8077056e>] rest_init+0x28/0xea
> [ 0.225429] [<ffffffff80800670>] arch_post_acpi_subsys_init+0x0/0x18
> [ 0.232460] [<ffffffff80800de4>] start_kernel+0x72c/0x75c
> [ 0.238434] ---[ end trace 0000000000000000 ]---
> n):0kB isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB kernel_stack:0kB pagetables:4kB sec_pagetables:0kB all_unreclaimable? no
> [ 0.423801] DMA32 free:940780kB boost:0kB min:0kB low:0kB high:0kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:1046528kB managed:940780kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> [ 0.452034] lowmem_reserve[]: 0 0 0
> [ 0.455919] Normal free:126248kB boost:0kB min:0kB low:0kB high:0kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:1048576kB managed:126820kB mlocked:0kB bounce:0kB free_pcp:156kB local_pcp:156kB free_cma:0kB
> [ 0.484652] lowmem_reserve[]: 0 0 0
> [ 0.488538] DMA32: 1*4kB (M) 1*8kB (M) 0*16kB 1*32kB (M) 1*64kB (M) 1*128kB (M) 0*256kB 1*512kB (M) 0*1024kB 1*2048kB (M) 229*4096kB (M) = 940780kB
> [ 0.503367] Normal: 2*4kB (ME) 0*8kB 2*16kB (UE) 2*32kB (ME) 3*64kB (UME) 0*128kB 2*256kB (ME) 3*512kB (UME) 3*1024kB (UME) 3*2048kB (UME) 28*4096kB (M) = 126248kB
> [ 0.519722] 0 total pagecache pages
> [ 0.523579] 0 pages in swap cache
> [ 0.527264] Free swap = 0kB
> [ 0.530445] Total swap = 0kB
> [ 0.533652] 523776 pages RAM
> [ 0.536833] 0 pages HighMem/MovableOnly
> [ 0.541090] 256876 pages reserved
> [ 0.544833] Unable to handle kernel NULL pointer dereference at virtual address 000000000000003c
> [ 0.554576] Oops [#1]
> [ 0.557092] Modules linked in:
> [ 0.560470] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 6.2.0-rc4-00538-g6e265f6be0c8 #1
> [ 0.570841] Hardware name: Microchip PolarFire-SoC Icicle Kit (DT)
> [ 0.577664] epc : rest_init+0x44/0xea
> [ 0.581726] ra : rest_init+0x44/0xea
> [ 0.585788] epc : ffffffff8077058a ra : ffffffff8077058a sp : ffffffff81203f70
> [ 0.593764] gp : ffffffff812e9fe0 tp : ffffffff8120fa80 t0 : 0000000000000000
> [ 0.601741] t1 : 0000000000000000 t2 : 0000000000000040 s0 : ffffffff81203f90
> [ 0.609718] s1 : fffffffffffffff4 a0 : 0000000000000000 a1 : fffffffffffffff4
> [ 0.617695] a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000
> [ 0.625672] a5 : 0000000000000000 a6 : 0000000001212dec a7 : ffffffffd8bc86ae
> [ 0.633649] s2 : ffffffff80de0bf0 s3 : ffffffe7c7de7700 s4 : 0000000000000000
> [ 0.641626] s5 : ffffffff812eb018 s6 : ffffffff80a00008 s7 : 0000000000000000
> [ 0.649603] s8 : 00000000bfb85036 s9 : 0000000000000000 s10: 0000000000000000
> [ 0.657580] s11: 0000000000000000 t3 : 0000000000000002 t4 : 0000000000000402
> [ 0.665557] t5 : ffffffff812158a8 t6 : 0000000000000000
> [ 0.671416] status: 0000000200000120 badaddr: 000000000000003c cause: 000000000000000d
> [ 0.680157] [<ffffffff80800670>] arch_post_acpi_subsys_init+0x0/0x18
> [ 0.687188] [<ffffffff80800de4>] start_kernel+0x72c/0x75c
> [ 0.693195] ---[ end trace 0000000000000000 ]---
> [ 0.698325] Kernel panic - not syncing: Attempted to kill the idle task!
> [ 0.705729] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]---

--
Sincerely yours,
Mike.