| Message ID | 20240812062017.2674441-1-ruanjinjie@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [-next,v2] crash: Fix riscv64 crash memory reserve dead loop | expand |
On Mon, Aug 12, 2024 at 02:20:17PM +0800, Jinjie Ruan wrote: > On RISCV64 Qemu machine with 512MB memory, cmdline "crashkernel=500M,high" > will cause system stall as below: > > Zone ranges: > DMA32 [mem 0x0000000080000000-0x000000009fffffff] > Normal empty > Movable zone start for each node > Early memory node ranges > node 0: [mem 0x0000000080000000-0x000000008005ffff] > node 0: [mem 0x0000000080060000-0x000000009fffffff] > Initmem setup node 0 [mem 0x0000000080000000-0x000000009fffffff] > (stall here) > > commit 5d99cadf1568 ("crash: fix x86_32 crash memory reserve dead loop > bug") fix this on 32-bit architecture. However, the problem is not > completely solved. If `CRASH_ADDR_LOW_MAX = CRASH_ADDR_HIGH_MAX` on 64-bit > architecture, for example, when system memory is equal to > CRASH_ADDR_LOW_MAX on RISCV64, the following infinite loop will also occur: > > -> reserve_crashkernel_generic() and high is true > -> alloc at [CRASH_ADDR_LOW_MAX, CRASH_ADDR_HIGH_MAX] fail > -> alloc at [0, CRASH_ADDR_LOW_MAX] fail and repeatedly > (because CRASH_ADDR_LOW_MAX = CRASH_ADDR_HIGH_MAX). > > As Catalin suggested, do not remove the ",high" reservation fallback to > ",low" logic which will change arm64's kdump behavior, but fix it by > skipping the above situation similar to commit d2f32f23190b ("crash: fix > x86_32 crash memory reserve dead loop"). > > After this patch, it print: > cannot allocate crashkernel (size:0x1f400000) > > Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> > Suggested-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Thanks.
On 08/12/24 at 02:20pm, Jinjie Ruan wrote: > On RISCV64 Qemu machine with 512MB memory, cmdline "crashkernel=500M,high" > will cause system stall as below: > > Zone ranges: > DMA32 [mem 0x0000000080000000-0x000000009fffffff] > Normal empty > Movable zone start for each node > Early memory node ranges > node 0: [mem 0x0000000080000000-0x000000008005ffff] > node 0: [mem 0x0000000080060000-0x000000009fffffff] > Initmem setup node 0 [mem 0x0000000080000000-0x000000009fffffff] > (stall here) > > commit 5d99cadf1568 ("crash: fix x86_32 crash memory reserve dead loop > bug") fix this on 32-bit architecture. However, the problem is not > completely solved. If `CRASH_ADDR_LOW_MAX = CRASH_ADDR_HIGH_MAX` on 64-bit > architecture, for example, when system memory is equal to > CRASH_ADDR_LOW_MAX on RISCV64, the following infinite loop will also occur: > > -> reserve_crashkernel_generic() and high is true > -> alloc at [CRASH_ADDR_LOW_MAX, CRASH_ADDR_HIGH_MAX] fail > -> alloc at [0, CRASH_ADDR_LOW_MAX] fail and repeatedly > (because CRASH_ADDR_LOW_MAX = CRASH_ADDR_HIGH_MAX). > > As Catalin suggested, do not remove the ",high" reservation fallback to > ",low" logic which will change arm64's kdump behavior, but fix it by > skipping the above situation similar to commit d2f32f23190b ("crash: fix > x86_32 crash memory reserve dead loop"). > > After this patch, it print: > cannot allocate crashkernel (size:0x1f400000) > > Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> > Suggested-by: Catalin Marinas <catalin.marinas@arm.com> > --- > v2: > - Fix it in another way suggested by Catalin. > - Add Suggested-by. > --- > kernel/crash_reserve.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) Acked-by: Baoquan He <bhe@redhat.com> > > diff --git a/kernel/crash_reserve.c b/kernel/crash_reserve.c > index 5387269114f6..aae4a9e998d1 100644 > --- a/kernel/crash_reserve.c > +++ b/kernel/crash_reserve.c > @@ -427,7 +427,8 @@ void __init reserve_crashkernel_generic(char *cmdline, > if (high && search_end == CRASH_ADDR_HIGH_MAX) { > search_end = CRASH_ADDR_LOW_MAX; > search_base = 0; > - goto retry; > + if (search_end != CRASH_ADDR_HIGH_MAX) > + goto retry; > } > pr_warn("cannot allocate crashkernel (size:0x%llx)\n", > crash_size); > -- > 2.34.1 >
diff --git a/kernel/crash_reserve.c b/kernel/crash_reserve.c index 5387269114f6..aae4a9e998d1 100644 --- a/kernel/crash_reserve.c +++ b/kernel/crash_reserve.c @@ -427,7 +427,8 @@ void __init reserve_crashkernel_generic(char *cmdline, if (high && search_end == CRASH_ADDR_HIGH_MAX) { search_end = CRASH_ADDR_LOW_MAX; search_base = 0; - goto retry; + if (search_end != CRASH_ADDR_HIGH_MAX) + goto retry; } pr_warn("cannot allocate crashkernel (size:0x%llx)\n", crash_size);
On RISCV64 Qemu machine with 512MB memory, cmdline "crashkernel=500M,high" will cause system stall as below: Zone ranges: DMA32 [mem 0x0000000080000000-0x000000009fffffff] Normal empty Movable zone start for each node Early memory node ranges node 0: [mem 0x0000000080000000-0x000000008005ffff] node 0: [mem 0x0000000080060000-0x000000009fffffff] Initmem setup node 0 [mem 0x0000000080000000-0x000000009fffffff] (stall here) commit 5d99cadf1568 ("crash: fix x86_32 crash memory reserve dead loop bug") fix this on 32-bit architecture. However, the problem is not completely solved. If `CRASH_ADDR_LOW_MAX = CRASH_ADDR_HIGH_MAX` on 64-bit architecture, for example, when system memory is equal to CRASH_ADDR_LOW_MAX on RISCV64, the following infinite loop will also occur: -> reserve_crashkernel_generic() and high is true -> alloc at [CRASH_ADDR_LOW_MAX, CRASH_ADDR_HIGH_MAX] fail -> alloc at [0, CRASH_ADDR_LOW_MAX] fail and repeatedly (because CRASH_ADDR_LOW_MAX = CRASH_ADDR_HIGH_MAX). As Catalin suggested, do not remove the ",high" reservation fallback to ",low" logic which will change arm64's kdump behavior, but fix it by skipping the above situation similar to commit d2f32f23190b ("crash: fix x86_32 crash memory reserve dead loop"). After this patch, it print: cannot allocate crashkernel (size:0x1f400000) Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Suggested-by: Catalin Marinas <catalin.marinas@arm.com> --- v2: - Fix it in another way suggested by Catalin. - Add Suggested-by. --- kernel/crash_reserve.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)