The patch titled Subject: mm/alloc_tag: fix panic when CONFIG_KASAN enabled and CONFIG_KASAN_VMALLOC not enabled has been added to the -mm mm-hotfixes-unstable branch. Its filename is alloc_tag-fix-module-allocation-tags-populated-area-calculation-fix-2.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/alloc_tag-fix-module-allocation-tags-populated-area-calculation-fix-2.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Hao Ge <gehao@xxxxxxxxxx> Subject: mm/alloc_tag: fix panic when CONFIG_KASAN enabled and CONFIG_KASAN_VMALLOC not enabled Date: Thu, 12 Dec 2024 15:21:26 +0800 When CONFIG_KASAN is enabled but CONFIG_KASAN_VMALLOC is not enabled, we may encounter a panic during system boot. Because we haven't allocated pages and created mappings for the shadow memory corresponding to module allocation tags region,similar to how it is done for execmem_vmalloc. The memory for module allocation tags is allocated on demand, therefore we need to allocate shadow memory on demand as well in MODULE_ALIGN blocks. Here is the log for panic: [ 18.349421] BUG: unable to handle page fault for address: fffffbfff8092000 [ 18.350016] #PF: supervisor read access in kernel mode [ 18.350459] #PF: error_code(0x0000) - not-present page [ 18.350904] PGD 20fe52067 P4D 219dc8067 PUD 219dc4067 PMD 102495067 PTE 0 [ 18.351484] Oops: Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI [ 18.351961] CPU: 5 UID: 0 PID: 1 Comm: systemd Not tainted 6.13.0-rc1+ #3 [ 18.352533] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 [ 18.353494] RIP: 0010:kasan_check_range+0xba/0x1b0 [ 18.353931] Code: 8d 5a 07 4c 0f 49 da 49 c1 fb 03 45 85 db 0f 84 dd 00 00 00 45 89 db 4a 8d 14 d8 eb 0d 48 83 c0 08 48 39 c2 0f 84 c1 00 00 00 <48> 83 38 00 74 ed 48 8d 50 08 eb 0d 48 83 c0 01 48 39 d0 0f 84 90 [ 18.355484] RSP: 0018:ff11000101877958 EFLAGS: 00010206 [ 18.355937] RAX: fffffbfff8092000 RBX: fffffbfff809201e RCX: ffffffff82a7ceac [ 18.356542] RDX: fffffbfff8092018 RSI: 00000000000000f0 RDI: ffffffffc0490000 [ 18.357153] RBP: fffffbfff8092000 R08: 0000000000000001 R09: fffffbfff809201d [ 18.357756] R10: ffffffffc04900ef R11: 0000000000000003 R12: ffffffffc0490000 [ 18.358365] R13: ff11000101877b48 R14: ffffffffc0490000 R15: 000000000000002c [ 18.358968] FS: 00007f9bd13c5940(0000) GS:ff110001eb480000(0000) knlGS:0000000000000000 [ 18.359648] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 18.360178] CR2: fffffbfff8092000 CR3: 0000000109214004 CR4: 0000000000771ef0 [ 18.360790] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 18.361404] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 18.362020] PKRU: 55555554 [ 18.362261] Call Trace: [ 18.362481] <TASK> [ 18.362671] ? __die+0x23/0x70 [ 18.362964] ? page_fault_oops+0xc2/0x160 [ 18.363318] ? exc_page_fault+0xad/0xc0 [ 18.363680] ? asm_exc_page_fault+0x26/0x30 [ 18.364056] ? move_module+0x3cc/0x8a0 [ 18.364398] ? kasan_check_range+0xba/0x1b0 [ 18.364755] __asan_memcpy+0x3c/0x60 [ 18.365074] move_module+0x3cc/0x8a0 [ 18.365386] layout_and_allocate.constprop.0+0x3d5/0x720 [ 18.365841] ? early_mod_check+0x3dc/0x510 [ 18.366195] load_module+0x72/0x1850 [ 18.366509] ? __pfx_kernel_read_file+0x10/0x10 [ 18.366918] ? vm_mmap_pgoff+0x21c/0x2d0 [ 18.367262] init_module_from_file+0xd1/0x130 [ 18.367638] ? __pfx_init_module_from_file+0x10/0x10 [ 18.368073] ? __pfx__raw_spin_lock+0x10/0x10 [ 18.368456] ? __pfx_cred_has_capability.isra.0+0x10/0x10 [ 18.368938] idempotent_init_module+0x22c/0x790 [ 18.369332] ? simple_getattr+0x6f/0x120 [ 18.369676] ? __pfx_idempotent_init_module+0x10/0x10 [ 18.370110] ? fdget+0x58/0x3a0 [ 18.370393] ? security_capable+0x64/0xf0 [ 18.370745] __x64_sys_finit_module+0xc2/0x140 [ 18.371136] do_syscall_64+0x7d/0x160 [ 18.371459] ? fdget_pos+0x1c8/0x4c0 [ 18.371784] ? ksys_read+0xfd/0x1d0 [ 18.372106] ? syscall_exit_to_user_mode+0x10/0x1f0 [ 18.372525] ? do_syscall_64+0x89/0x160 [ 18.372860] ? do_syscall_64+0x89/0x160 [ 18.373194] ? do_syscall_64+0x89/0x160 [ 18.373527] ? syscall_exit_to_user_mode+0x10/0x1f0 [ 18.373952] ? do_syscall_64+0x89/0x160 [ 18.374283] ? syscall_exit_to_user_mode+0x10/0x1f0 [ 18.374701] ? do_syscall_64+0x89/0x160 [ 18.375037] ? do_user_addr_fault+0x4a8/0xa40 [ 18.375416] ? clear_bhb_loop+0x25/0x80 [ 18.375748] ? clear_bhb_loop+0x25/0x80 [ 18.376119] ? clear_bhb_loop+0x25/0x80 [ 18.376450] entry_SYSCALL_64_after_hwframe+0x76/0x7e Link: https://lkml.kernel.org/r/20241212072126.134572-1-hao.ge@xxxxxxxxx Fixes: 233e89322cbe ("alloc_tag: fix module allocation tags populated area calculation") Signed-off-by: Hao Ge <gehao@xxxxxxxxxx> Reported-by: Ben Greear <greearb@xxxxxxxxxxxxxxx> Closes: https://lore.kernel.org/all/1ba0cc57-e2ed-caa2-1241-aa5615bee01f@xxxxxxxxxxxxxxx/ Suggested-by: Suren Baghdasaryan <surenb@xxxxxxxxxx> Acked-by: Suren Baghdasaryan <surenb@xxxxxxxxxx> Tested-by: Adrian Huang <ahuang12@xxxxxxxxxx> Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/alloc_tag.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) --- a/lib/alloc_tag.c~alloc_tag-fix-module-allocation-tags-populated-area-calculation-fix-2 +++ a/lib/alloc_tag.c @@ -414,6 +414,8 @@ static int vm_module_tags_populate(void) if (phys_end < new_end) { struct page **next_page = vm_module_tags->pages + vm_module_tags->nr_pages; + unsigned long old_shadow_end = ALIGN(phys_end, MODULE_ALIGN); + unsigned long new_shadow_end = ALIGN(new_end, MODULE_ALIGN); unsigned long more_pages; unsigned long nr; @@ -428,7 +430,19 @@ static int vm_module_tags_populate(void) __free_page(next_page[i]); return -ENOMEM; } + vm_module_tags->nr_pages += nr; + + /* + * Kasan allocates 1 byte of shadow for every 8 bytes of data. + * When kasan_alloc_module_shadow allocates shadow memory, + * its unit of allocation is a page. + * Therefore, here we need to align to MODULE_ALIGN. + */ + if (old_shadow_end < new_shadow_end) + kasan_alloc_module_shadow((void *)old_shadow_end, + new_shadow_end - old_shadow_end, + GFP_KERNEL); } /* _ Patches currently in -mm which might be from gehao@xxxxxxxxxx are alloc_tag-fix-module-allocation-tags-populated-area-calculation-fix.patch alloc_tag-fix-module-allocation-tags-populated-area-calculation-fix-2.patch