From: John Thomson git@johnthomson.fastmail.com.au
commit 7c18b64bba3bcad1be94b404f47b94a04b91ce79 upstream.
With CONFIG_SLUB=y, following commit 6edf2576a6cc ("mm/slub: enable debugging memory wasting of kmalloc") mt7621 failed to boot very early, without showing any console messages. This exposed the pre-existing bug of mt7621.c using kzalloc before normal memory management was available. Prior to this slub change, there existed the unintended protection against "kmem_cache *s" being NULL as slab_pre_alloc_hook() happened to return NULL and bailed out of slab_alloc_node(). This allowed mt7621 prom_soc_init to fail in the soc_dev_init kzalloc, but continue booting without the SOC_BUS driver device registered.
Console output from a DEBUG_ZBOOT vmlinuz kernel loading, with mm/slub modified to warn on kmem_cache zero or null:
zimage at: 80B842A0 810B4BC0 Uncompressing Linux at load address 80001000 Copy device tree to address 80B80EE0 Now, booting the kernel...
[ 0.000000] Linux version 6.1.0-rc3+ (john@john) (mipsel-buildroot-linux-gnu-gcc.br_real (Buildroot 2021.11-4428-g6b6741b) 12.2.0, GNU ld (GNU Binutils) 2.39) #73 SMP Wed Nov 2 05:10:01 AEST 2022 [ 0.000000] ------------[ cut here ]------------ [ 0.000000] WARNING: CPU: 0 PID: 0 at mm/slub.c:3416 kmem_cache_alloc+0x5a4/0x5e8 [ 0.000000] Modules linked in: [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 6.1.0-rc3+ #73 [ 0.000000] Stack : 810fff78 80084d98 00000000 00000004 00000000 00000000 80889d04 80c90000 [ 0.000000] 80920000 807bd328 8089d368 80923bd3 00000000 00000001 80889cb0 00000000 [ 0.000000] 00000000 00000000 807bd328 8084bcb1 00000002 00000002 00000001 6d6f4320 [ 0.000000] 00000000 80c97d3d 80c97d68 fffffffc 807bd328 00000000 00000000 00000000 [ 0.000000] 00000000 a0000000 80910000 8110a0b4 00000000 00000020 80010000 80010000 [ 0.000000] ... [ 0.000000] Call Trace: [ 0.000000] [<80008260>] show_stack+0x28/0xf0 [ 0.000000] [<8070c958>] dump_stack_lvl+0x60/0x80 [ 0.000000] [<8002e184>] __warn+0xc4/0xf8 [ 0.000000] [<8002e210>] warn_slowpath_fmt+0x58/0xa4 [ 0.000000] [<801c0fac>] kmem_cache_alloc+0x5a4/0x5e8 [ 0.000000] [<8092856c>] prom_soc_init+0x1fc/0x2b4 [ 0.000000] [<80928060>] prom_init+0x44/0xf0 [ 0.000000] [<80929214>] setup_arch+0x4c/0x6a8 [ 0.000000] [<809257e0>] start_kernel+0x88/0x7c0 [ 0.000000] [ 0.000000] ---[ end trace 0000000000000000 ]--- [ 0.000000] SoC Type: MediaTek MT7621 ver:1 eco:3 [ 0.000000] printk: bootconsole [early0] enabled
Allowing soc_device_register to work exposed oops in the mt7621 phy pci, and pci controller drivers from soc_device_match_attr, due to missing sentinels in the quirks tables. These were fixed with: commit 819b885cd886 ("phy: ralink: mt7621-pci: add sentinel to quirks table") not yet applied ("PCI: mt7621: add sentinel to quirks table")
Link: https://lore.kernel.org/linux-mm/becf2ac3-2a90-4f3a-96d9-a70f67c66e4a@app.fa... Fixes: 71b9b5e0130d ("MIPS: ralink: mt7621: introduce 'soc_device' initialization") Signed-off-by: John Thomson git@johnthomson.fastmail.com.au Signed-off-by: Thomas Bogendoerfer tsbogend@alpha.franken.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/mips/ralink/mt7621.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)
--- a/arch/mips/ralink/mt7621.c +++ b/arch/mips/ralink/mt7621.c @@ -25,6 +25,7 @@ #define MT7621_MEM_TEST_PATTERN 0xaa5555aa
static u32 detect_magic __initdata; +static struct ralink_soc_info *soc_info_ptr;
int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge) { @@ -147,27 +148,30 @@ static const char __init *mt7621_get_soc return "E1"; }
-static void soc_dev_init(struct ralink_soc_info *soc_info) +static int __init mt7621_soc_dev_init(void) { struct soc_device *soc_dev; struct soc_device_attribute *soc_dev_attr;
soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL); if (!soc_dev_attr) - return; + return -ENOMEM;
soc_dev_attr->soc_id = "mt7621"; soc_dev_attr->family = "Ralink"; soc_dev_attr->revision = mt7621_get_soc_revision();
- soc_dev_attr->data = soc_info; + soc_dev_attr->data = soc_info_ptr;
soc_dev = soc_device_register(soc_dev_attr); if (IS_ERR(soc_dev)) { kfree(soc_dev_attr); - return; + return PTR_ERR(soc_dev); } + + return 0; } +device_initcall(mt7621_soc_dev_init);
void __init prom_soc_init(struct ralink_soc_info *soc_info) { @@ -209,7 +213,7 @@ void __init prom_soc_init(struct ralink_
soc_info->mem_detect = mt7621_memory_detect;
- soc_dev_init(soc_info); + soc_info_ptr = soc_info;
if (!register_cps_smp_ops()) return;