On Jun 15, 2019, at 3:15 PM, Sasha Levin sashal@kernel.org wrote:

Hi,

[This is an automated email]

This commit has been processed because it contains a "Fixes:" tag, fixing commit: ff3cc952d3f0 resource: Add remove_resource interface.

The bot has tested the following trees: v5.1.9, v4.19.50, v4.14.125, v4.9.181.

v5.1.9: Build OK! v4.19.50: Failed to apply! Possible dependencies: 010a93bf97c7 ("resource: Fix find_next_iomem_res() iteration issue") a98959fdbda1 ("resource: Include resource end in walk_*() interfaces")

v4.14.125: Failed to apply! Possible dependencies: 010a93bf97c7 ("resource: Fix find_next_iomem_res() iteration issue") 0e4c12b45aa8 ("x86/mm, resource: Use PAGE_KERNEL protection for ioremap of memory pages") 1d2e733b13b4 ("resource: Provide resource struct in resource walk callback") 4ac2aed837cb ("resource: Consolidate resource walking code") a98959fdbda1 ("resource: Include resource end in walk_*() interfaces")

v4.9.181: Failed to apply! Possible dependencies: 010a93bf97c7 ("resource: Fix find_next_iomem_res() iteration issue") 0e4c12b45aa8 ("x86/mm, resource: Use PAGE_KERNEL protection for ioremap of memory pages") 1d2e733b13b4 ("resource: Provide resource struct in resource walk callback") 4ac2aed837cb ("resource: Consolidate resource walking code") 60fe3910bb02 ("kexec_file: Allow arch-specific memory walking for kexec_add_buffer") a0458284f062 ("powerpc: Add support code for kexec_file_load()") a98959fdbda1 ("resource: Include resource end in walk_*() interfaces") da6658859b9c ("powerpc: Change places using CONFIG_KEXEC to use CONFIG_KEXEC_CORE instead.") ec2b9bfaac44 ("kexec_file: Change kexec_add_buffer to take kexec_buf as argument.")

Is there a reason 010a93bf97c7 ("resource: Fix find_next_iomem_res() iteration issue”) was not backported?

For 4.19 the following passes compilation.

-- >8 --

From: Nadav Amit namit@vmware.com Subject: [PATCH] resource: Fix locking in find_next_iomem_res()

Since resources can be removed, locking should ensure that the resource is not removed while accessing it. However, find_next_iomem_res() does not hold the lock while copying the data of the resource. Keep holding the lock while the data is copied.

Fixes: ff3cc952d3f00 ("resource: Add remove_resource interface") Cc: stable@vger.kernel.org Cc: Borislav Petkov bp@suse.de Cc: Toshi Kani toshi.kani@hpe.com Cc: Peter Zijlstra peterz@infradead.org Cc: Dave Hansen dave.hansen@linux.intel.com Cc: Dan Williams dan.j.williams@intel.com Cc: Bjorn Helgaas bhelgaas@google.com Cc: Ingo Molnar mingo@kernel.org Signed-off-by: Nadav Amit namit@vmware.com --- kernel/resource.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/kernel/resource.c b/kernel/resource.c index 30e1bc68503b..0201feade7d5 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -331,6 +331,7 @@ static int find_next_iomem_res(struct resource *res, unsigned long desc, resource_size_t start, end; struct resource *p; bool sibling_only = false; + int r = 0;

BUG_ON(!res);

@@ -356,9 +357,11 @@ static int find_next_iomem_res(struct resource *res, unsigned long desc, break; }

- read_unlock(&resource_lock); - if (!p) - return -1; + if (!p) { + r = -1; + goto out; + } + /* copy data */ if (res->start < p->start) res->start = p->start; @@ -366,7 +369,9 @@ static int find_next_iomem_res(struct resource *res, unsigned long desc, res->end = p->end; res->flags = p->flags; res->desc = p->desc; - return 0; +out: + read_unlock(&resource_lock); + return r; }

static int __walk_iomem_res_desc(struct resource *res, unsigned long desc,