Re: [RFC PATCH 3/3] mips: ralink: mt7621: do not use kzalloc too early
From: Sergio Paracuellos
Date: Fri Nov 04 2022 - 08:29:47 EST
Hi John,
On Thu, Nov 3, 2022 at 6:25 PM Sergio Paracuellos
<sergio.paracuellos@xxxxxxxxx> wrote:
>
> Hi John,
>
> Thanks for the patches!
>
> On Thu, Nov 3, 2022 at 12:15 PM John Thomson
> <lists@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > On Thu, 3 Nov 2022, at 05:05, John Thomson wrote:
> > > 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 this soc device.
> > >
> > > 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
>
> Last version I tested on my gnubee PC1 mt7621 board was v6.0 and all
> was booting properly.
I have verified with 6.1.0-rc1 system does not boot as you was pointed out here.
After adding your patches the system boots and got an Oops because
soc_device_match_attr:
[ 20.569959] CPU 0 Unable to handle kernel paging request at virtual
address 675f6b6c, epc == 80403dec, ra == 804ae11c
[ 20.591060] Oops[#1]:
[ 20.595462] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.1.0-rc1+ #148
[ 20.608265] $ 0 : 00000000 00000001 82262a00 00000000
[ 20.618615] $ 4 : 675f6b6c 808dea04 00000000 804ae138
[ 20.628983] $ 8 : 00000000 808787ba 00000000 821f4b00
[ 20.639351] $12 : 0000005b 0000005d 0000002d 0000005c
[ 20.649735] $16 : 82253580 807b4034 807b4034 804ae138
[ 20.660087] $20 : fffffff4 82c382b8 809e1094 00000008
[ 20.670455] $24 : 0000002a 0000003f
[ 20.680823] $28 : 82050000 82051c30 80a0d638 804ae11c
[ 20.691190] Hi : 00000037
[ 20.696891] Lo : 5c28f6a0
[ 20.702610] epc : 80403dec glob_match+0x1c/0x240
[ 20.712100] ra : 804ae11c soc_device_match_attr+0xac/0xc8
[ 20.723330] Status: 11000403 KERNEL EXL IE
[ 20.731626] Cause : 40800008 (ExcCode 02)
[ 20.739576] BadVA : 675f6b6c
[ 20.745277] PrId : 0001992f (MIPS 1004Kc)
[ 20.753414] Modules linked in:
[ 20.759448] Process swapper/0 (pid: 1, threadinfo=(ptrval),
task=(ptrval), tls=00000000)
[ 20.775520] Stack : fffffff4 80496ab8 820c6010 828c8518 80950000
ffffffea 80950000 80496b48
[ 20.792106] 00000000 828c8400 820c6010 821f4880 1e160000
821bc754 82253734 7f8268e6
[ 20.808707] 809c6a94 807b4034 804ae138 809c8e88 819a0000
804ae1d8 80a0d638 80438e10
[ 20.825282] 821f3e70 80950000 808c0000 828c8400 820c6000
828c8548 820c6010 80456608
[ 20.841879] 821f3dc0 821d32c0 819a0000 801d8768 821f3dc0
821d32c0 828c8540 80950000
[ 20.858473] ...
[ 20.863298] Call Trace:
[ 20.868137] [<80403dec>] glob_match+0x1c/0x240
[ 20.876955] [<804ae11c>] soc_device_match_attr+0xac/0xc8
[ 20.887500] [<80496b48>] bus_for_each_dev+0x7c/0xc0
[ 20.897176] [<804ae1d8>] soc_device_match+0x98/0xc8
[ 20.906869] [<80456608>] mt7621_pcie_probe+0x90/0x7b8
[ 20.916876] [<8049b46c>] platform_probe+0x54/0x94
[ 20.926206] [<80499058>] really_probe+0x200/0x434
[ 20.935538] [<80499520>] driver_probe_device+0x44/0xd4
[ 20.945732] [<80499ae0>] __driver_attach+0xb8/0x1b0
[ 20.955428] [<80496b48>] bus_for_each_dev+0x7c/0xc0
[ 20.965089] [<80497f18>] bus_add_driver+0x100/0x218
[ 20.974763] [<8049a338>] driver_register+0xd0/0x118
[ 20.984438] [<80001590>] do_one_initcall+0x8c/0x28c
[ 20.994115] [<809e21c8>] kernel_init_freeable+0x254/0x28c
[ 21.004845] [<80781070>] kernel_init+0x24/0x118
[ 21.013830] [<800034f8>] ret_from_kernel_thread+0x14/0x1c
[ 21.024522]
[ 21.027457] Code: 240f005c 2418002a 2419003f <80820000> 24a90001
90a70000 104c006f 24860001 2843005c
[ 21.046810]
[ 21.049830] ---[ end trace 0000000000000000 ]---
[ 21.058935] Kernel panic - not syncing: Fatal exception
[ 21.069310] Rebooting in 1 seconds..
I have fixed this adding two sentinels in the following files:
drivers/pci/controller/pcie-mt7621.c
drivers/phy/ralink/phy-mt7621-pci.c
sergio@camaron:~/GNUBEE-SERGIO-TEST/linux$ git diff
drivers/pci/controller/pcie-mt7621.c
drivers/phy/ralink/phy-mt7621-pci.c
diff --git a/drivers/pci/controller/pcie-mt7621.c
b/drivers/pci/controller/pcie-mt7621.c
index 4bd1abf26008..ee7aad09d627 100644
--- a/drivers/pci/controller/pcie-mt7621.c
+++ b/drivers/pci/controller/pcie-mt7621.c
@@ -466,7 +466,8 @@ static int mt7621_pcie_register_host(struct
pci_host_bridge *host)
}
static const struct soc_device_attribute mt7621_pcie_quirks_match[] = {
- { .soc_id = "mt7621", .revision = "E2" }
+ { .soc_id = "mt7621", .revision = "E2" },
+ { /* sentinel */ }
};
static int mt7621_pcie_probe(struct platform_device *pdev)
diff --git a/drivers/phy/ralink/phy-mt7621-pci.c
b/drivers/phy/ralink/phy-mt7621-pci.c
index 5e6530f545b5..85888ab2d307 100644
--- a/drivers/phy/ralink/phy-mt7621-pci.c
+++ b/drivers/phy/ralink/phy-mt7621-pci.c
@@ -280,7 +280,8 @@ static struct phy *mt7621_pcie_phy_of_xlate(struct
device *dev,
}
static const struct soc_device_attribute mt7621_pci_quirks_match[] = {
- { .soc_id = "mt7621", .revision = "E2" }
+ { .soc_id = "mt7621", .revision = "E2" },
+ { /* sentinel */ }
};
static const struct regmap_config mt7621_pci_phy_regmap_config = {
With this two minor changes and your patches the system properly boots
and behaves properly.
So FWIW feel free to add my:
Tested-by: Sergio Paracuellos <sergio.paracuellos@xxxxxxxxx>
Acked-by: Sergio Paracuellos <sergio.paracuellos@xxxxxxxxx>
Please, let me know if you want me to send any patches or if you are
going to create a complete patchset with all the needed changes.
Thank you very much for doing this!
Best regards,
Sergio Paracuellos
[snip]