On 3/23/19 10:06 PM, Matthew Wilcox wrote:
> Thanks for testing. Kirill suggests this would be a better fix:
>
> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> index 41858a3744b4..9718393ae45b 100644
> --- a/include/linux/pagemap.h
> +++ b/include/linux/pagemap.h
> @@ -334,10 +334,12 @@ static inline struct page *grab_cache_page_nowait(struct address_space *mapping,
>
> static inline struct page *find_subpage(struct page *page, pgoff_t offset)
> {
> + unsigned long index = page_index(page);
> +
> VM_BUG_ON_PAGE(PageTail(page), page);
> - VM_BUG_ON_PAGE(page->index > offset, page);
> - VM_BUG_ON_PAGE(page->index + compound_nr(page) <= offset, page);
> - return page - page->index + offset;
> + VM_BUG_ON_PAGE(index > offset, page);
> + VM_BUG_ON_PAGE(index + compound_nr(page) <= offset, page);
> + return page - index + offset;
> }
>
> struct page *find_get_entry(struct address_space *mapping, pgoff_t offset);
This is not even compiled.
If "s/compound_nr/compound_order/", it failed to boot here,
[ 56.843236] Unpacking initramfs...
[ 56.881979] page:ffff7fe022eb19c0 count:3 mapcount:0 mapping:38ff80080099c008
index:0x0
[ 56.890007] ramfs_aops
[ 56.890011] name:"lvm.conf"
[ 56.892465] flags: 0x17fffffa400000c(uptodate|dirty)
[ 56.900318] raw: 017fffffa400000c dead000000000100 dead000000000200
38ff80080099c008
[ 56.908066] raw: 0000000000000000 0000000000000000 00000003ffffffff
7bff8008203bcc80
[ 56.915812] page dumped because: VM_BUG_ON_PAGE(index + compound_order(page)
<= offset)
[ 56.923818] page->mem_cgroup:7bff8008203bcc80
[ 56.928180] page allocated via order 0, migratetype Unmovable, gfp_mask
0x100cc2(GFP_HIGHUSER)
[ 56.936800] prep_new_page+0x4e0/0x5e0
[ 56.940556] get_page_from_freelist+0x4cf4/0x50e0
[ 56.945265] __alloc_pages_nodemask+0x738/0x38b8
[ 56.949888] alloc_page_interleave+0x34/0x2f0
[ 56.954249] alloc_pages_current+0xc0/0x150
[ 56.958439] __page_cache_alloc+0x70/0x2f4
[ 56.962541] pagecache_get_page+0x5e4/0xaf0
[ 56.966729] grab_cache_page_write_begin+0x6c/0x98
[ 56.971526] simple_write_begin+0x40/0x308
[ 56.975627] generic_perform_write+0x1d4/0x4e0
[ 56.980076] __generic_file_write_iter+0x294/0x504
[ 56.984872] generic_file_write_iter+0x354/0x594
[ 56.989496] __vfs_write+0x72c/0x8a0
[ 56.993076] vfs_write+0x1ec/0x424
[ 56.996481] ksys_write+0xbc/0x190
[ 56.999890] xwrite+0x38/0x84
[ 57.002869] ------------[ cut here ]------------
[ 57.007478] kernel BUG at ./include/linux/pagemap.h:342!
[ 57.012801] Internal error: Oops - BUG: 0 [#1] SMP
[ 57.017584] Modules linked in:
[ 57.020636] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.1.0-rc1-mm1+ #7
[ 57.027239] Hardware name: HPE Apollo 70 /C01_APACHE_MB ,
BIOS L50_5.13_1.0.6 07/10/2018
[ 57.037057] pstate: 60400009 (nZCv daif +PAN -UAO)
[ 57.041839] pc : find_get_entry+0x948/0x950
[ 57.046013] lr : find_get_entry+0x940/0x950
[ 57.050185] sp : 10ff80082600f420
[ 57.053489] x29: 10ff80082600f4d0 x28: efff100000000000
[ 57.058792] x27: ffff7fe022eb19c8 x26: 0000000000000010
[ 57.064095] x25: 0000000000000035 x24: 0000000000000003
[ 57.069397] x23: 00000000000000ff x22: 10ff80082600f460
[ 57.074700] x21: ffff7fe022eb19c0 x20: 35ff800825f9a050
[ 57.080002] x19: 0000000000000000 x18: 0000000000000000
[ 57.085304] x17: 0000000000000000 x16: 000000000000000a
[ 57.090606] x15: 35ff800825f9a0b8 x14: 0000000000000000
[ 57.095908] x13: ffff800825f9a050 x12: 00000000ffffffff
[ 57.101210] x11: 0000000000000003 x10: 00000000000000ff
[ 57.106512] x9 : e071b95619aca700 x8 : e071b95619aca700
[ 57.111814] x7 : 0000000000000000 x6 : ffff1000102d01f4
[ 57.117116] x5 : 0000000000000000 x4 : 0000000000000080
[ 57.122418] x3 : ffff1000102b84c8 x2 : 0000000000000000
[ 57.127720] x1 : 0000000000000004 x0 : ffff100013316b10
[ 57.133024] Process swapper/0 (pid: 1, stack limit = 0x(____ptrval____))
[ 57.139715] Call trace:
[ 57.142153] find_get_entry+0x948/0x950
[ 57.145979] pagecache_get_page+0x68/0xaf0
[ 57.150066] grab_cache_page_write_begin+0x6c/0x98
[ 57.154847] simple_write_begin+0x40/0x308
[ 57.158934] generic_perform_write+0x1d4/0x4e0
[ 57.163368] __generic_file_write_iter+0x294/0x504
[ 57.168150] generic_file_write_iter+0x354/0x594
[ 57.172757] __vfs_write+0x72c/0x8a0
[ 57.176323] vfs_write+0x1ec/0x424
[ 57.179715] ksys_write+0xbc/0x190
[ 57.183107] xwrite+0x38/0x84
[ 57.186066] do_copy+0x110/0x898
[ 57.189284] write_buffer+0x148/0x1cc
[ 57.192937] flush_buffer+0x94/0x240
[ 57.196505] __gunzip+0x738/0x8f0
[ 57.199810] gunzip+0x18/0x20
[ 57.202768] unpack_to_rootfs+0x358/0x968
[ 57.206769] populate_rootfs+0x120/0x198
[ 57.210684] do_one_initcall+0x544/0xd00
[ 57.214597] do_initcall_level+0x660/0x814
[ 57.218684] do_basic_setup+0x38/0x50
[ 57.222337] kernel_init_freeable+0x25c/0x444
[ 57.226686] kernel_init+0x1c/0x548
[ 57.230165] ret_from_fork+0x10/0x18
[ 57.233733] Code: aa1503e0 94034d79 b0016fe0 912c4000 (d4210000)
[ 57.240055] ---[ end trace d7c5c3c62a7fa743 ]---
[ 57.244664] Kernel panic - not syncing: Fatal exception
[ 57.249997] SMP: stopping secondary CPUs
[ 57.254417] ---[ end Kernel panic - not syncing: Fatal exception ]---
