(added Andrey Konovalov) On Thu, Jan 31, 2019 at 07:15:26AM +0100, Christophe Leroy wrote: > > Le 31/01/2019 à 07:06, Stephen Rothwell a écrit : > >Hi all, > > > >On Thu, 31 Jan 2019 16:38:54 +1100 Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote: > >> > >>[I am guessing that is is something in Andrew's tree that has caused > >>this.] > >> > >>My qemu boot of the powerpc pseries_le_defconfig config failed like this: > >> > >>htab_hash_mask = 0x1ffff > >>----------------------------------------------------- > >>numa: NODE_DATA [mem 0x7ffe7000-0x7ffebfff] > >>Kernel panic - not syncing: sparse_buffer_init: Failed to allocate 2147483648 bytes align=0x10000 nid=0 from=fffffffffffffff > >>CPU: 0 PID: 0 Comm: swapper Not tainted 5.0.0-rc4 #2 > >>Call Trace: > >>[c00000000105bbd0] [c000000000b1345c] dump_stack+0xb0/0xf4 (unreliable) > >>[c00000000105bc10] [c000000000111120] panic+0x168/0x3b8 > >>[c00000000105bcb0] [c000000000e701c8] sparse_init_nid+0x178/0x550 > >>[c00000000105bd70] [c000000000e709b4] sparse_init+0x210/0x238 > >>[c00000000105bdb0] [c000000000e468f4] initmem_init+0x1e0/0x260 > >>[c00000000105be80] [c000000000e3b9b0] setup_arch+0x354/0x3d4 > >>[c00000000105bef0] [c000000000e33afc] start_kernel+0x98/0x648 > >>[c00000000105bf90] [c00000000000b270] start_here_common+0x1c/0x52c > > > >A quick bisect leads to this: > > > >1c3c9328cde027eb875ba4692f0a5d66b0afe862 is the first bad commit > >commit 1c3c9328cde027eb875ba4692f0a5d66b0afe862 > >Author: Mike Rapoport <rppt@xxxxxxxxxxxxx> > >Date: Thu Jan 31 10:51:32 2019 +1100 > > > > treewide: add checks for the return value of memblock_alloc*() > > Add check for the return value of memblock_alloc*() functions and call > > panic() in case of error. The panic message repeats the one used by > > panicing memblock allocators with adjustment of parameters to include only > > relevant ones. > > > >Which is just adding the panic we hit. So, presumably, the bug is in a > >preceding patch :-( > > > >I have left the kernel not booting for today. > > > > No I think the error is really in that patch, see my other mail. > > See https://elixir.bootlin.com/linux/v5.0-rc4/source/mm/memblock.c#L1455, > memblock_alloc_try_nid_raw() is not supposed to panic, so the last hunk of > this patch should be reverted. > > Found in total three problematic hunks in that patch: > > @@ -48,6 +53,11 @@ static phys_addr_t __init kasan_alloc_raw_page(int node) > void *p = memblock_alloc_try_nid_raw(PAGE_SIZE, PAGE_SIZE, > __pa(MAX_DMA_ADDRESS), > MEMBLOCK_ALLOC_KASAN, node); > + if (!p) > + panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n", > + __func__, PAGE_SIZE, PAGE_SIZE, node, > + __pa(MAX_DMA_ADDRESS)); > + > return __pa(p); > } I've looked more closely to the code that uses this function and it does not seem to handle allocation error. I can replace the panic with WARN(), but I think that panic() here is appropriate. Andrey, can you comment? > @@ -211,6 +211,9 @@ static int __init iob_init(struct device_node *dn) > iob_l2_base = memblock_alloc_try_nid_raw(1UL << 21, 1UL << 21, > MEMBLOCK_LOW_LIMIT, 0x80000000, > NUMA_NO_NODE); > + if (!iob_l2_base) > + panic("%s: Failed to allocate %lu bytes align=0x%lx max_addr=%x\n", > + __func__, 1UL << 21, 1UL << 21, 0x80000000); > > pr_info("IOBMAP L2 allocated at: %p\n", iob_l2_base); This one is actually fixes my own mistake from one of the previous patches that converted memblock_alloc_base() to memblock_alloc_try_nid_raw() without adding the panic() (commit 47e382eb08cfa0199c4ea9f9cc73f1b48a3a4b1d "powerpc: prefer memblock APIs returning virtual address") > @@ -425,6 +436,10 @@ static void __init sparse_buffer_init(unsigned long > size, int nid) > memblock_alloc_try_nid_raw(size, PAGE_SIZE, > __pa(MAX_DMA_ADDRESS), > MEMBLOCK_ALLOC_ACCESSIBLE, nid); > + if (!sparsemap_buf) > + panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%lx\n", > + __func__, size, PAGE_SIZE, nid, __pa(MAX_DMA_ADDRESS)); > + > sparsemap_buf_end = sparsemap_buf + size; > } This hunk was not needed as sparse can deal with this allocation failure. Andrew, can you please add the below patch to as a fixup to "treewide: add checks for the return value of memblock_alloc*()"? >From 854f54b9d4fe52f477765b905a4b2c421d30f46e Mon Sep 17 00:00:00 2001 From: Mike Rapoport <rppt@xxxxxxxxxxxxx> Date: Thu, 31 Jan 2019 09:18:50 +0200 Subject: [PATCH] mm/sparse: don't panic if the allocation in sparse_buffer_init fails Addition of panic if memblock_alloc_try_nid_raw() call in sparse_buffer_init() fails was over enthusiastic as the system is perfectly capable to deal with that allocation failure. Remove the panic(). Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx> --- mm/sparse.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/mm/sparse.c b/mm/sparse.c index 1471f06..c11aba0 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -434,10 +434,6 @@ static void __init sparse_buffer_init(unsigned long size, int nid) memblock_alloc_try_nid_raw(size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS), MEMBLOCK_ALLOC_ACCESSIBLE, nid); - if (!sparsemap_buf) - panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%lx\n", - __func__, size, PAGE_SIZE, nid, __pa(MAX_DMA_ADDRESS)); - sparsemap_buf_end = sparsemap_buf + size; } -- 2.7.4
