module_alloc() first tries to allocate module text within 24 bits direct jump from kernel text, and tries a wider allocation if first one fails.
When first allocation fails the following is observed in kernel logs: vmap allocation for size 2400256 failed: use vmalloc=<size> to increase size systemd-udevd: vmalloc error: size 2395133, vm_struct allocation failed, mode:0xcc0(GFP_KERNEL), nodemask=(null) CPU: 0 PID: 127 Comm: systemd-udevd Tainted: G W 5.15.5-gentoo-PowerMacG4 #9 Call Trace: [e2a53a50] [c0ba0048] dump_stack_lvl+0x80/0xb0 (unreliable) [e2a53a70] [c0540128] warn_alloc+0x11c/0x2b4 [e2a53b50] [c0531be8] __vmalloc_node_range+0xd8/0x64c [e2a53c10] [c00338c0] module_alloc+0xa0/0xac [e2a53c40] [c027a368] load_module+0x2ae0/0x8148 [e2a53e30] [c027fc78] sys_finit_module+0xfc/0x130 [e2a53f30] [c0035098] ret_from_syscall+0x0/0x28 --- interrupt: c00 at 0x25df10 NIP: 0025df10 LR: 00416180 CTR: 00000000 REGS: e2a53f40 TRAP: 0c00 Tainted: G W (5.15.5-gentoo-PowerMacG4) MSR: 0000d032 <EE,PR,ME,IR,DR,RI> CR: 2822242c XER: 20000000 GPR00: 00000161 afa8f060 a73a6160 00000011 0041dfa5 00000000 00000011 00000000 GPR08: 00000000 20000000 0000007a afa8efe0 002113f8 0072f924 00000000 00000000 GPR16: 00000005 afa8f1fc afa8f1e8 00000000 22222422 00000000 009603b0 22222422 GPR24: 00000000 00000000 0041dfa5 008a5fc0 00020000 00000000 00444cc4 009958f0 NIP [0025df10] 0x25df10 LR [00416180] 0x416180 --- interrupt: c00 Mem-Info: active_anon:36 inactive_anon:4417 isolated_anon:0 active_file:3496 inactive_file:10535 isolated_file:0 unevictable:0 dirty:59 writeback:0 slab_reclaimable:3672 slab_unreclaimable:20540 mapped:5700 shmem:166 pagetables:185 bounce:0 kernel_misc_reclaimable:0 free:438282 free_pcp:1121 free_cma:0 Node 0 active_anon:144kB inactive_anon:17668kB active_file:13984kB inactive_file:42140kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:22800kB dirty:404kB writeback:0kB shmem:664kB writeback_tmp:0kB kernel_stack:1352kB pagetables:740kB all_unreclaimable? no DMA free:267900kB min:2488kB low:3108kB high:3728kB reserved_highatomic:4096KB active_anon:0kB inactive_anon:0kB active_file:4016kB inactive_file:4224kB unevictable:0kB writepending:76kB present:524288kB managed:389432kB mlocked:0kB bounce:0kB free_pcp:2480kB local_pcp:1176kB free_cma:0kB lowmem_reserve[]: 0 0 1536 1536 HighMem free:1485036kB min:512kB low:3032kB high:5552kB reserved_highatomic:0KB active_anon:136kB inactive_anon:17612kB active_file:9976kB inactive_file:37912kB unevictable:0kB writepending:364kB present:1572864kB managed:1572864kB mlocked:0kB bounce:0kB free_pcp:1776kB local_pcp:404kB free_cma:0kB BTRFS: selftest: sectorsize: 4096 nodesize: 8192 lowmem_reserve[]: 0 0 0 0 BTRFS: selftest: running btrfs free space cache tests DMA: 283*4kB (UMH) 282*8kB (UMH) 242*16kB (UMEH) 422*32kB (UMH) 187*64kB (UMH) 139*128kB (UME) 118*256kB (UM) 87*512kB (UME) 61*1024kB (UME) 27*2048kB (U) 6*4096kB (U) = 267612kB BTRFS: selftest: running extent only tests HighMem: 1*4kB (M) 1*8kB (M) 92*16kB (M) 43*32kB (UM) 21*64kB (M) 7*128kB (M) 3*256kB (UM) 1*512kB (U) 2*1024kB (UM) 1*2048kB (U) 360*4096kB (UM) = 1485036kB BTRFS: selftest: running bitmap only tests 14218 total pagecache pages 0 pages in swap cache Swap cache stats: add 0, delete 0, find 0/0 Free swap = 8388604kB Total swap = 8388604kB 524288 pages RAM 393216 pages HighMem/MovableOnly 33714 pages reserved Add __GFP_NOWARN flag to first allocation so that no warning appears when it fails. Reported-by: Erhard Furtner <erhar...@mailbox.org> Fixes: 2ec13df16704 ("powerpc/modules: Load modules closer to kernel text") Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu> --- arch/powerpc/kernel/module.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/kernel/module.c b/arch/powerpc/kernel/module.c index ed04a3ba66fe..40a583e9d3c7 100644 --- a/arch/powerpc/kernel/module.c +++ b/arch/powerpc/kernel/module.c @@ -90,16 +90,17 @@ int module_finalize(const Elf_Ehdr *hdr, } static __always_inline void * -__module_alloc(unsigned long size, unsigned long start, unsigned long end) +__module_alloc(unsigned long size, unsigned long start, unsigned long end, bool nowarn) { pgprot_t prot = strict_module_rwx_enabled() ? PAGE_KERNEL : PAGE_KERNEL_EXEC; + gfp_t gfp = GFP_KERNEL | (nowarn ? __GFP_NOWARN : 0); /* * Don't do huge page allocations for modules yet until more testing * is done. STRICT_MODULE_RWX may require extra work to support this * too. */ - return __vmalloc_node_range(size, 1, start, end, GFP_KERNEL, prot, + return __vmalloc_node_range(size, 1, start, end, gfp, prot, VM_FLUSH_RESET_PERMS | VM_NO_HUGE_VMAP, NUMA_NO_NODE, __builtin_return_address(0)); } @@ -114,13 +115,13 @@ void *module_alloc(unsigned long size) /* First try within 32M limit from _etext to avoid branch trampolines */ if (MODULES_VADDR < PAGE_OFFSET && MODULES_END > limit) - ptr = __module_alloc(size, limit, MODULES_END); + ptr = __module_alloc(size, limit, MODULES_END, true); if (!ptr) - ptr = __module_alloc(size, MODULES_VADDR, MODULES_END); + ptr = __module_alloc(size, MODULES_VADDR, MODULES_END, false); return ptr; #else - return __module_alloc(size, VMALLOC_START, VMALLOC_END); + return __module_alloc(size, VMALLOC_START, VMALLOC_END, false); #endif } -- 2.33.1