* FAILED: patch "[PATCH] powerpc/kexec_file: Fix division by zero in extra size" failed to apply to 5.15-stable tree
@ 2023-02-07 8:47 gregkh
0 siblings, 0 replies; only message in thread
From: gregkh @ 2023-02-07 8:47 UTC (permalink / raw)
To: mpe; +Cc: stable
The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
Possible dependencies:
7294194b47e9 ("powerpc/kexec_file: Fix division by zero in extra size estimation")
340a4a9f8773 ("powerpc: Take in account addition CPU node when building kexec FDT")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 7294194b47e994753a86eee8cf1c61f3f36458a3 Mon Sep 17 00:00:00 2001
From: Michael Ellerman <mpe@ellerman.id.au>
Date: Mon, 30 Jan 2023 12:47:07 +1100
Subject: [PATCH] powerpc/kexec_file: Fix division by zero in extra size
estimation
In kexec_extra_fdt_size_ppc64() there's logic to estimate how much
extra space will be needed in the device tree for some memory related
properties.
That logic uses the size of RAM divided by drmem_lmb_size() to do the
estimation. However drmem_lmb_size() can be zero if the machine has no
hotpluggable memory configured, which is the case when booting with qemu
and no maxmem=x parameter is passed (the default).
The division by zero is reported by UBSAN, and can also lead to an
overflow and a warning from kvmalloc, and kdump kernel loading fails:
WARNING: CPU: 0 PID: 133 at mm/util.c:596 kvmalloc_node+0x15c/0x160
Modules linked in:
CPU: 0 PID: 133 Comm: kexec Not tainted 6.2.0-rc5-03455-g07358bd97810 #223
Hardware name: IBM pSeries (emulated by qemu) POWER9 (raw) 0x4e1200 0xf000005 of:SLOF,git-dd0dca pSeries
NIP: c00000000041ff4c LR: c00000000041fe58 CTR: 0000000000000000
REGS: c0000000096ef750 TRAP: 0700 Not tainted (6.2.0-rc5-03455-g07358bd97810)
MSR: 800000000282b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 24248242 XER: 2004011e
CFAR: c00000000041fed0 IRQMASK: 0
...
NIP kvmalloc_node+0x15c/0x160
LR kvmalloc_node+0x68/0x160
Call Trace:
kvmalloc_node+0x68/0x160 (unreliable)
of_kexec_alloc_and_setup_fdt+0xb8/0x7d0
elf64_load+0x25c/0x4a0
kexec_image_load_default+0x58/0x80
sys_kexec_file_load+0x5c0/0x920
system_call_exception+0x128/0x330
system_call_vectored_common+0x15c/0x2ec
To fix it, skip the calculation if drmem_lmb_size() is zero.
Fixes: 2377c92e37fe ("powerpc/kexec_file: fix FDT size estimation for kdump kernel")
Cc: stable@vger.kernel.org # v5.12+
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230130014707.541110-1-mpe@ellerman.id.au
diff --git a/arch/powerpc/kexec/file_load_64.c b/arch/powerpc/kexec/file_load_64.c
index af8854f9eae3..19d084682bc2 100644
--- a/arch/powerpc/kexec/file_load_64.c
+++ b/arch/powerpc/kexec/file_load_64.c
@@ -989,10 +989,13 @@ unsigned int kexec_extra_fdt_size_ppc64(struct kimage *image)
* linux,drconf-usable-memory properties. Get an approximate on the
* number of usable memory entries and use for FDT size estimation.
*/
- usm_entries = ((memblock_end_of_DRAM() / drmem_lmb_size()) +
- (2 * (resource_size(&crashk_res) / drmem_lmb_size())));
-
- extra_size = (unsigned int)(usm_entries * sizeof(u64));
+ if (drmem_lmb_size()) {
+ usm_entries = ((memblock_end_of_DRAM() / drmem_lmb_size()) +
+ (2 * (resource_size(&crashk_res) / drmem_lmb_size())));
+ extra_size = (unsigned int)(usm_entries * sizeof(u64));
+ } else {
+ extra_size = 0;
+ }
/*
* Get the number of CPU nodes in the current DT. This allows to
^ permalink raw reply related [flat|nested] only message in thread
only message in thread, other threads:[~2023-02-07 8:48 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-02-07 8:47 FAILED: patch "[PATCH] powerpc/kexec_file: Fix division by zero in extra size" failed to apply to 5.15-stable tree gregkh
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.