From: "yang.zhang" <yang.zhang@xxxxxxxxxxxx> When loading segments, ubytes is <= mbytes. When ubytes is exhausted, there could be remaining mbytes. Then in the while loop, the buf pointer advancing with mchunk will causing meaningless reading even though it doesn't harm. So let's change to make sure that all of the copying and the rest only happens before uchunk goes to zero. Acked-by: Baoquan He <bhe@xxxxxxxxxx> Signed-off-by: yang.zhang <yang.zhang@xxxxxxxxxxxx> --- V2 -> V3: - Add more detailed description in the commit message v1 -> v2: - Only copy before uchunk goes to zero V1: https://lore.kernel.org/lkml/20240130101802.23850-1-gaoshanliukou@xxxxxxx/ --- kernel/kexec_core.c | 44 ++++++++++++++++++++++++-------------------- 1 file changed, 24 insertions(+), 20 deletions(-) diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index d08fc7b5db97..2fc3d0e3715a 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -800,22 +800,24 @@ static int kimage_load_normal_segment(struct kimage *image, PAGE_SIZE - (maddr & ~PAGE_MASK)); uchunk = min(ubytes, mchunk); - /* For file based kexec, source pages are in kernel memory */ - if (image->file_mode) - memcpy(ptr, kbuf, uchunk); - else - result = copy_from_user(ptr, buf, uchunk); + if (uchunk) { + /* For file based kexec, source pages are in kernel memory */ + if (image->file_mode) + memcpy(ptr, kbuf, uchunk); + else + result = copy_from_user(ptr, buf, uchunk); + ubytes -= uchunk; + if (image->file_mode) + kbuf += uchunk; + else + buf += uchunk; + } kunmap_local(ptr); if (result) { result = -EFAULT; goto out; } - ubytes -= uchunk; maddr += mchunk; - if (image->file_mode) - kbuf += mchunk; - else - buf += mchunk; mbytes -= mchunk; cond_resched(); @@ -866,11 +868,18 @@ static int kimage_load_crash_segment(struct kimage *image, memset(ptr + uchunk, 0, mchunk - uchunk); } - /* For file based kexec, source pages are in kernel memory */ - if (image->file_mode) - memcpy(ptr, kbuf, uchunk); - else - result = copy_from_user(ptr, buf, uchunk); + if (uchunk) { + /* For file based kexec, source pages are in kernel memory */ + if (image->file_mode) + memcpy(ptr, kbuf, uchunk); + else + result = copy_from_user(ptr, buf, uchunk); + ubytes -= uchunk; + if (image->file_mode) + kbuf += uchunk; + else + buf += uchunk; + } kexec_flush_icache_page(page); kunmap_local(ptr); arch_kexec_pre_free_pages(page_address(page), 1); @@ -878,12 +887,7 @@ static int kimage_load_crash_segment(struct kimage *image, result = -EFAULT; goto out; } - ubytes -= uchunk; maddr += mchunk; - if (image->file_mode) - kbuf += mchunk; - else - buf += mchunk; mbytes -= mchunk; cond_resched(); -- 2.25.1 _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
