On 2022/8/27 4:25, Nathan Chancellor wrote:
Hi Liu,
On Thu, Aug 25, 2022 at 10:20:36PM +0800, Liu Shixin wrote:
In the initialization of zswap, about 18MB memory will be allocated for
zswap_pool in my machine. Since not all users use zswap, the memory may be
wasted. Save the memory for these users by delaying the initialization of
zswap to first enablement.
Signed-off-by: Liu Shixin <liushixin2@xxxxxxxxxx>
---
...
This change is in -next as commit 22100432cf14 ("mm/zswap: delay the
initializaton of zswap until the first enablement"). I just bisected my
arm64 test system running Fedora failing to boot due to that commit,
with the following stack trace:
Unable to handle kernel access to user memory outside uaccess routines at virtual address 0000000000000000
Mem abort info:
ESR = 0x0000000096000004
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x04: level 0 translation fault
Data abort info:
ISV = 0, ISS = 0x00000004
CM = 0, WnR = 0
user pgtable: 4k pages, 48-bit VAs, pgdp=00000020a4fab000
[0000000000000000] pgd=0000000000000000, p4d=0000000000000000
Internal error: Oops: 96000004 [#1] SMP
Modules linked in: zram fsl_dpaa2_eth pcs_lynx phylink ahci_qoriq crct10dif_ce ghash_ce sbsa_gwdt fsl_mc_dpio nvme lm90 nvme_core at803x xhci_plat_hcd rtc_fsl_ftm_alarm xgmac_mdio ahci_platform i2c_imx ip6_tables ip_tables fuse
Unloaded tainted modules: cppc_cpufreq():1
CPU: 10 PID: 761 Comm: swapon Not tainted 6.0.0-rc2-00454-g22100432cf14 #1
Hardware name: SolidRun Ltd. SolidRun CEX7 Platform, BIOS EDK II Jun 21 2022
pstate: 00400005 (nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : frontswap_init+0x38/0x60
lr : __do_sys_swapon+0x8a8/0x9f4
sp : ffff80000969bcf0
x29: ffff80000969bcf0 x28: ffff37bee0d8fc00 x27: ffff80000a7f5000
x26: fffffcdefb971e80 x25: ffffaba797453b90 x24: 0000000000000064
x23: ffff37c1f209d1a8 x22: ffff37bee880e000 x21: ffffaba797748560
x20: ffff37bee0d8fce4 x19: ffffaba797748488 x18: 0000000000000014
x17: 0000000030ec029a x16: ffffaba795a479b0 x15: 0000000000000000
x14: 0000000000000000 x13: 0000000000000030 x12: 0000000000000001
x11: ffff37c63c0aba18 x10: 0000000000000000 x9 : ffffaba7956b8c88
x8 : ffff80000969bcd0 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000001 x4 : 0000000000000000 x3 : ffffaba79730f000
x2 : ffff37bee0d8fc00 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
frontswap_init+0x38/0x60
__do_sys_swapon+0x8a8/0x9f4
__arm64_sys_swapon+0x28/0x3c
invoke_syscall+0x78/0x100
el0_svc_common.constprop.0+0xd4/0xf4
do_el0_svc+0x38/0x4c
el0_svc+0x34/0x10c
el0t_64_sync_handler+0x11c/0x150
el0t_64_sync+0x190/0x194
Code: d000e283 910003fd f9006c41 f946d461 (f9400021)
---[ end trace 0000000000000000 ]---
This is with Fedora's configuration:
https://src.fedoraproject.org/rpms/kernel/raw/rawhide/f/kernel-aarch64-fedora.config
If there is any more information I can provide or patches I can test, I
am more than happy to do so!
Thanks for your reporting，we will check it.
Cheers,
Nathan
.
