kernel/linux.git/fs/proc/vmcore.c, branch v6.1.168

fs/proc: fix softlockup in __read_vmcore (part 2)

2025-01-23T16:17:14+00:00

commit cbc5dde0a461240046e8a41c43d7c3b76d5db952 upstream. Since commit 5cbcb62dddf5 ("fs/proc: fix softlockup in __read_vmcore") the number of softlockups in __read_vmcore at kdump time have gone down, but they still happen sometimes. In a memory constrained environment like the kdump image, a softlockup is not just a harmless message, but it can interfere with things like RCU freeing memory, causing the crashdump to get stuck. The second loop in __read_vmcore has a lot more opportunities for natural sleep points, like scheduling out while waiting for a data write to happen, but apparently that is not always enough. Add a cond_resched() to the second loop in __read_vmcore to (hopefully) get rid of the softlockups. Link: https://lkml.kernel.org/r/20250110102821.2a37581b@fangorn Fixes: 5cbcb62dddf5 ("fs/proc: fix softlockup in __read_vmcore") Signed-off-by: Rik van Riel Reported-by: Breno Leitao Cc: Baoquan He Cc: Dave Young Cc: Vivek Goyal Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

fs/proc: fix compile warning about variable 'vmcore_mmap_ops'

2024-11-14T12:15:18+00:00

commit b8ee299855f08539e04d6c1a6acb3dc9e5423c00 upstream. When build with !CONFIG_MMU, the variable 'vmcore_mmap_ops' is defined but not used: >> fs/proc/vmcore.c:458:42: warning: unused variable 'vmcore_mmap_ops' 458 | static const struct vm_operations_struct vmcore_mmap_ops = { Fix this by only defining it when CONFIG_MMU is enabled. Link: https://lkml.kernel.org/r/20241101034803.9298-1-xiqi2@huawei.com Fixes: 9cb218131de1 ("vmcore: introduce remap_oldmem_pfn_range()") Signed-off-by: Qi Xi Reported-by: kernel test robot Closes: https://lore.kernel.org/lkml/202410301936.GcE8yUos-lkp@intel.com/ Cc: Baoquan He Cc: Dave Young Cc: Michael Holzheu Cc: Vivek Goyal Cc: Wang ShaoBo Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

fs/proc: fix softlockup in __read_vmcore

2024-06-21T12:35:56+00:00

commit 5cbcb62dddf5346077feb82b7b0c9254222d3445 upstream. While taking a kernel core dump with makedumpfile on a larger system, softlockup messages often appear. While softlockup warnings can be harmless, they can also interfere with things like RCU freeing memory, which can be problematic when the kdump kexec image is configured with as little memory as possible. Avoid the softlockup, and give things like work items and RCU a chance to do their thing during __read_vmcore by adding a cond_resched. Link: https://lkml.kernel.org/r/20240507091858.36ff767f@imladris.surriel.com Signed-off-by: Rik van Riel Acked-by: Baoquan He Cc: Dave Young Cc: Vivek Goyal Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

proc/vmcore: fix signedness bug in read_from_oldmem()

2023-08-03T08:24:14+00:00

commit 641db40f3afe7998011bfabc726dba3e698f8196 upstream. The bug is the error handling: if (tmp < nr_bytes) { "tmp" can hold negative error codes but because "nr_bytes" is type size_t the negative error codes are treated as very high positive values (success). Fix this by changing "nr_bytes" to type ssize_t. The "nr_bytes" variable is used to store values between 1 and PAGE_SIZE and they can fit in ssize_t without any issue. Link: https://lkml.kernel.org/r/b55f7eed-1c65-4adc-95d1-6c7c65a54a6e@moroto.mountain Fixes: 5d8de293c224 ("vmcore: convert copy_oldmem_page() to take an iov_iter") Signed-off-by: Dan Carpenter Reviewed-by: Matthew Wilcox (Oracle) Acked-by: Baoquan He Cc: Dave Young Cc: Vivek Goyal Cc: Alexey Dobriyan Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

use less confusing names for iov_iter direction initializers

2023-02-09T10:28:04+00:00

[ Upstream commit de4eda9de2d957ef2d6a8365a01e26a435e958cb ] READ/WRITE proved to be actively confusing - the meanings are "data destination, as used with read(2)" and "data source, as used with write(2)", but people keep interpreting those as "we read data from it" and "we write data to it", i.e. exactly the wrong way. Call them ITER_DEST and ITER_SOURCE - at least that is harder to misinterpret... Signed-off-by: Al Viro Stable-dep-of: 6dd88fd59da8 ("vhost-scsi: unbreak any layout for response") Signed-off-by: Sasha Levin

proc: delete unused includes

2022-07-18T00:31:39+00:00

Those aren't necessary after seq files won. Link: https://lkml.kernel.org/r/YqnA3mS7KBt8Z4If@localhost.localdomain Signed-off-by: Alexey Dobriyan Signed-off-by: Andrew Morton

vmcore: convert read_from_oldmem() to take an iov_iter

2022-04-29T21:37:59+00:00

Remove the read_from_oldmem() wrapper introduced earlier and convert all the remaining callers to pass an iov_iter. Link: https://lkml.kernel.org/r/20220408090636.560886-4-bhe@redhat.com Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Baoquan He Reviewed-by: Christoph Hellwig Cc: Tiezhu Yang Cc: Amit Daniel Kachhap Cc: Al Viro Cc: Matthew Wilcox Signed-off-by: Andrew Morton

vmcore: convert __read_vmcore to use an iov_iter

2022-04-29T21:37:59+00:00

This gets rid of copy_to() and let us use proc_read_iter() instead of proc_read(). Link: https://lkml.kernel.org/r/20220408090636.560886-3-bhe@redhat.com Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Baoquan He Reviewed-by: Christoph Hellwig Signed-off-by: Andrew Morton

vmcore: convert copy_oldmem_page() to take an iov_iter

2022-04-29T21:37:59+00:00

Patch series "Convert vmcore to use an iov_iter", v5. For some reason several people have been sending bad patches to fix compiler warnings in vmcore recently. Here's how it should be done. Compile-tested only on x86. As noted in the first patch, s390 should take this conversion a bit further, but I'm not inclined to do that work myself. This patch (of 3): Instead of passing in a 'buf' and 'userbuf' argument, pass in an iov_iter. s390 needs more work to pass the iov_iter down further, or refactor, but I'd be more comfortable if someone who can test on s390 did that work. It's more convenient to convert the whole of read_from_oldmem() to take an iov_iter at the same time, so rename it to read_from_oldmem_iter() and add a temporary read_from_oldmem() wrapper that creates an iov_iter. Link: https://lkml.kernel.org/r/20220408090636.560886-1-bhe@redhat.com Link: https://lkml.kernel.org/r/20220408090636.560886-2-bhe@redhat.com Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Baoquan He Reviewed-by: Christoph Hellwig Cc: Heiko Carstens Signed-off-by: Andrew Morton

proc/vmcore: fix vmcore_alloc_buf() kernel-doc comment

2022-03-24T02:00:33+00:00

Fix a spelling problem to remove warnings found by running scripts/kernel-doc, which is caused by using 'make W=1'. fs/proc/vmcore.c:492: warning: Function parameter or member 'size' not described in 'vmcore_alloc_buf' fs/proc/vmcore.c:492: warning: Excess function parameter 'sizez' description in 'vmcore_alloc_buf' Link: https://lkml.kernel.org/r/20220129011449.105278-1-yang.lee@linux.alibaba.com Signed-off-by: Yang Li Reported-by: Abaci Robot Acked-by: Baoquan He Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds