[fixme!] a hack applied to skip ramoops pmsg write user date exception.

[   13.702813][    T1] file system registered
[   13.905931][  T156] Unable to handle kernel paging request at virtual address ffff80000bc00013
[   13.919148][  T156] Mem abort info:
[   13.926204][  T156]   ESR = 0x0000000096000061
[   13.934130][  T156]   EC = 0x25: DABT (current EL), IL = 32 bits
[   13.943647][  T156]   SET = 0, FnV = 0
[   13.950792][  T156]   EA = 0, S1PTW = 0
[   13.958046][  T156]   FSC = 0x21: alignment fault
[   13.966206][  T156] Data abort info:
[   13.973200][  T156]   ISV = 0, ISS = 0x00000061
[   13.981146][  T156]   CM = 0, WnR = 1
[   13.988232][  T156] swapper pgtable: 4k pages, 48-bit VAs, pgdp=00000000a2e80000
[   13.999244][  T156] [ffff80000bc00013] pgd=10000001fffff003, p4d=10000001fffff003, pud=10000001ffffe003, pmd=1000000100de5003, pte=006800009da00f0f
[   14.019729][  T156] Internal error: Oops: 0000000096000061 [#1] PREEMPT SMP
[   14.030265][  T156] Modules linked in:
[   14.037488][  T156] CPU: 6 PID: 156 Comm: servicemanager Tainted: G        W          6.2.0-rc8-01153-ge547a3f8ffed-dirty torvalds#397 875419ac35738882635cc222f82d9ee02b2c1883
[   14.059663][  T156] Hardware name: Qualcomm Technologies, Inc. SM7125 IDP (DT)
[   14.070537][  T156] pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[   14.081867][  T156] pc : __arch_copy_from_user+0xc0/0x230
[   14.090929][  T156] lr : persistent_ram_update_user+0x124/0x224
[   14.100508][  T156] sp : ffff80000ce33b30
[   14.108115][  T156] x29: ffff80000ce33b30 x28: ffff0000872c6600 x27: 0000000000000000
[   14.119681][  T156] x26: 0000000000000000 x25: 000000000000000b x24: ffff000080d5d900
[   14.131254][  T156] x23: 000000000000000b x22: 0000000000000007 x21: 000000000000000b
[   14.142832][  T156] x20: ffff80000bc00013 x19: 0000fffff0da2528 x18: ffff80000a5ab2f0
[   14.154425][  T156] x17: 0000000000000028 x16: 0000000000009063 x15: 0000fffff0da2528
[   14.166039][  T156] x14: 00000000ffffffff x13: 00000000000419c0 x12: 0000000000040000
[   14.177660][  T156] x11: 000000000001ffff x10: ffff0000872c6fe0 x9 : ffff80000ac1f330
[   14.189309][  T156] x8 : ffff0000872c6600 x7 : 0000000048590358 x6 : ffff80000bc00013
[   14.200950][  T156] x5 : ffff80000bc0001e x4 : 0000fffff0da2528 x3 : df0000000d009c02
[   14.212598][  T156] x2 : 000000000000000b x1 : 0000fffff0da2530 x0 : ffff80000bc00013
[   14.224267][  T156] Call trace:
[   14.231087][  T156]  __arch_copy_from_user+0xc0/0x230
[   14.239896][  T156]  persistent_ram_write_user+0x74/0x10c
[   14.249053][  T156]  ramoops_pstore_write_user+0x34/0x50
[   14.258143][  T156]  write_pmsg+0xd0/0x120
[   14.265962][  T156]  do_iter_write+0x174/0x200
[   14.274156][  T156]  vfs_writev+0x70/0xc0
[   14.281895][  T156]  do_writev+0x74/0x130
[   14.289648][  T156]  __arm64_sys_writev+0x20/0x30
[   14.298098][  T156]  invoke_syscall+0x48/0x114
[   14.306307][  T156]  el0_svc_common.constprop.0+0x60/0x11c
[   14.315580][  T156]  do_el0_svc+0x38/0xc0
[   14.323367][  T156]  el0_svc+0x48/0xc0
[   14.330843][  T156]  el0t_64_sync_handler+0xb8/0xbc
[   14.339493][  T156]  el0t_64_sync+0x194/0x198
[   14.347606][  T156] Code: a88120c7 36180082 f8400823 91002021 (f80084c3)
[   14.358230][  T156] ---[ end trace 0000000000000000 ]---
[   14.372981][  T156] Kernel panic - not syncing: Oops: Fatal exception
[   14.383267][  T156] SMP: stopping secondary CPUs
[   14.391731][  T156] Kernel Offset: 0x80000 from 0xffff800008000000
[   14.401761][  T156] PHYS_OFFSET: 0x80000000
[   14.409742][  T156] CPU features: 0x80000,040a0108,cc00720b
[   14.419163][  T156] Memory Limit: none
[   14.432312][  T156] Rebooting in 5 seconds..

fs/pstore/pmsg.c

@@ -17,6 +17,8 @@ static ssize_t write_pmsg(struct file *file, const char __user *buf,
 	struct pstore_record record;
 	int ret;
 
+	return -EFAULT;
+
 	if (!count)
 		return 0;