Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'pstore-v4.19-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull pstore fix from Kees Cook:
"This fixes a 6 year old pstore bug that everyone just got lucky in
avoiding, likely due only using page-aligned persistent ram regions:
- Handle page-vs-byte offset handling between iomap and vmap (Bin Yang)"
* tag 'pstore-v4.19-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
pstore: Fix incorrect persistent ram buffer mapping
+14
-3
+14
-3
fs/pstore/ram_core.c
+14
-3
fs/pstore/ram_core.c
···
429
429
vaddr = vmap(pages, page_count, VM_MAP, prot);
430
430
kfree(pages);
431
431
432
-
return vaddr;
432
+
/*
433
+
* Since vmap() uses page granularity, we must add the offset
434
+
* into the page here, to get the byte granularity address
435
+
* into the mapping to represent the actual "start" location.
436
+
*/
437
+
return vaddr + offset_in_page(start);
433
438
}
434
439
435
440
static void *persistent_ram_iomap(phys_addr_t start, size_t size,
···
453
448
else
454
449
va = ioremap_wc(start, size);
455
450
451
+
/*
452
+
* Since request_mem_region() and ioremap() are byte-granularity
453
+
* there is no need handle anything special like we do when the
454
+
* vmap() case in persistent_ram_vmap() above.
455
+
*/
456
456
return va;
457
457
}
458
458
···
478
468
return -ENOMEM;
479
469
}
480
470
481
-
prz->buffer = prz->vaddr + offset_in_page(start);
471
+
prz->buffer = prz->vaddr;
482
472
prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
483
473
484
474
return 0;
···
525
515
526
516
if (prz->vaddr) {
527
517
if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
528
-
vunmap(prz->vaddr);
518
+
/* We must vunmap() at page-granularity. */
519
+
vunmap(prz->vaddr - offset_in_page(prz->paddr));
529
520
} else {
530
521
iounmap(prz->vaddr);
531
522
release_mem_region(prz->paddr, prz->size);