Examples with J9MemTagCheckError com.ibm.j9ddr.vm29.pointer.helper.J9MemTagHelper.J9MemTagCheckError used on opensource projects

Example 1 with J9MemTagCheckError

use of com.ibm.j9ddr.vm29.pointer.helper.J9MemTagHelper.J9MemTagCheckError in project openj9 by eclipse.

the class J9MemTagIterator method internalNext.

private J9MemTagPointer internalNext() {
    long result;
    this.isFooterCorrupted = false;
    /* Hunt for the header eyecatcher */
    do {
        result = DataType.getProcess().findPattern(headerEyecatcherBytes, UDATA.SIZEOF, currentSearchAddress);
        if (result == -1) {
            return null;
        }
        if (Addresses.greaterThan(result, topAddress)) {
            return null;
        }
        /* Move the current search address beyond the current result */
        currentSearchAddress = result + UDATA.SIZEOF;
        /* Address is in range - does it point to a valid block? */
        VoidPointer memoryBase = j9mem_get_memory_base(J9MemTagPointer.cast(result));
        try {
            IDATA corruption = j9mem_check_tags(VoidPointer.cast(memoryBase), headerEyecatcher, footerEyecatcher);
            if (corruption.allBitsIn(J9PORT_MEMTAG_NOT_A_TAG.longValue())) {
                /* This is not a memory tag */
                continue;
            }
            if (corruption.allBitsIn(J9PORT_MEMTAG_FOOTER_TAG_CORRUPTED.longValue()) || corruption.allBitsIn(J9PORT_MEMTAG_FOOTER_PADDING_CORRUPTED.longValue())) {
                /*
					 * A block with corrupted footer is accepted only and only if 
					 * we are dealing with freed memory. Therefore, following check is double check.
					 * If we are here, then it is freed memory is being looked for with the current algorithm. 
					 *	
					 */
                if (headerEyecatcher == J9MEMTAG_EYECATCHER_FREED_HEADER && footerEyecatcher == J9MEMTAG_EYECATCHER_FREED_FOOTER) {
                    this.isFooterCorrupted = true;
                    return J9MemTagPointer.cast(result);
                }
            }
        } catch (J9MemTagCheckError e) {
            /* Tag is readable, but corrupt */
            if (!lookingForFreedCallSites) {
                EventManager.raiseCorruptDataEvent("Corrupt memory section found", e, false);
            }
            /* Find the next section */
            continue;
        }
        return J9MemTagPointer.cast(result);
    } while (true);
}

Example 2 with J9MemTagCheckError

use of com.ibm.j9ddr.vm29.pointer.helper.J9MemTagHelper.J9MemTagCheckError in project openj9 by eclipse.

the class J9MemTagHelper method j9mem_check_tags.

/**
 * Performs validation checks on the memory block starting at memoryPointer.
 *
 * The memory passed in could fall into one of three categories:
 * 1) It could be a valid J9MemTag region with valid headers and footers
 * 2) It could be not be a J9MemTag region
 * 3) It could be a J9MemTag region with some corruption in either the header, footer or padding
 *
 * @param[in] portLibrary The port library
 * @param[in] memoryPointer address returned by @ref j9mem_allocate_memory()
 *
 * @throws CorruptDataException if the tags are corrupted, or the memory is inaccessible. (Option 3)
 * @return J9PORT_MEMTAG_NOT_A_TAG if memoryPointer address is not a tag
 * 		   J9PORT_MEMTAG_HEADER_TAG_CORRUPTED if memoryPointer address is valid tag region but header tag is corrupted.
 * 		   J9PORT_MEMTAG_FOOTER_TAG_CORRUPTED if memoryPointer address is valid tag region but footer tag is corrupted.
 * 		   J9PORT_MEMTAG_FOOTER_PADDING_CORRUPTED if memoryPointer address is valid tag region but footer padding is corrupted.
 * 		   J9PORT_MEMTAG_VALID_TAG if memoryPointer address is valid tag and header/footer are not corrupted.
 * @note memoryPointer may not be NULL.
 */
public static IDATA j9mem_check_tags(VoidPointer memoryPointer, long headerEyecatcher, long footerEyecatcher) throws J9MemTagCheckError {
    J9MemTagPointer headerTagAddress, footerTagAddress = J9MemTagPointer.NULL;
    headerTagAddress = j9mem_get_header_tag(memoryPointer);
    try {
        footerTagAddress = j9mem_get_footer_tag(headerTagAddress);
        checkTagSumCheck(headerTagAddress, headerEyecatcher);
    } catch (J9MemTagCheckError e) {
        /* Corruption here either means the header tag is mangled, or the header eyecatcher isn't actually the start of a 
			 * J9MemTag block.
			 * 
			 * If we can find a valid footerTag, then we'll believe this is a mangled header.
			 */
        try {
            if (checkEyecatcher(footerTagAddress, footerEyecatcher)) {
                /* Footer eyecatcher is valid - header tag is corrupt */
                throw e;
            } else {
                /* Footer eyecatcher is invalid - this isn't a memory tag */
                return J9PORT_MEMTAG_NOT_A_TAG;
            }
        } catch (CorruptDataException e1) {
            /* Can't read the footer tag - assume memoryPointer isn't a tag */
            return J9PORT_MEMTAG_NOT_A_TAG;
        }
    } catch (CorruptDataException e) {
        /* CorruptDataException here will mean MemoryFault. Which means we can't read the 
			 * entire header tag - so we assume this isn't a valid J9MemTag
			 */
        return J9PORT_MEMTAG_NOT_A_TAG;
    }
    try {
        checkTagSumCheck(footerTagAddress, footerEyecatcher);
    } catch (J9MemTagCheckError e) {
        if (headerEyecatcher == J9MEMTAG_EYECATCHER_FREED_HEADER && footerEyecatcher == J9MEMTAG_EYECATCHER_FREED_FOOTER) {
            /* When dealing with already freed memory, it is reasonable to accept
				 * a block that is missing the footer instead of throwing an exception.
				 */
            return J9PORT_MEMTAG_FOOTER_TAG_CORRUPTED;
        } else {
            throw e;
        }
    } catch (CorruptDataException e) {
        /* If we got here, the header was valid. A memory fault here suggests
			 * we're missing the storage for the footer - which is corruption
			 */
        throw new J9MemTagCheckError(headerTagAddress, e);
    }
    try {
        checkPadding(headerTagAddress);
    } catch (J9MemTagCheckError e) {
        if (headerEyecatcher == J9MEMTAG_EYECATCHER_FREED_HEADER && footerEyecatcher == J9MEMTAG_EYECATCHER_FREED_FOOTER) {
            /* When dealing with already freed memory, it is reasonable to accept
				 * a block that is missing the footer instead of throwing an exception.
				 */
            return J9PORT_MEMTAG_FOOTER_PADDING_CORRUPTED;
        } else {
            throw e;
        }
    } catch (CorruptDataException e) {
        /* If we got here, the header was valid. A memory fault here suggests
			 * we're missing the storage for the padding - which is corruption
			 */
        throw new J9MemTagCheckError(headerTagAddress, e);
    }
    return J9PORT_MEMTAG_VALID_TAG;
}

Example 3 with J9MemTagCheckError

use of com.ibm.j9ddr.vm29.pointer.helper.J9MemTagHelper.J9MemTagCheckError in project openj9 by eclipse.

the class J9MemTagHelper method checkTagSumCheck.

/**
 * Checks that the memory tag is not corrupt.
 *
 * @param[in] tagAddress the in-process or out-of-process address of the
 *            header/footer memory tag
 * @param[in] eyeCatcher the eyecatcher corresponding to the memory tag
 *
 * @return 0 if the sum check is successful, non-zero otherwise
 * @throws CorruptDataException
 */
public static void checkTagSumCheck(J9MemTagPointer tag, long eyeCatcher) throws CorruptDataException {
    int sum = 0;
    U32Pointer slots;
    if (!checkEyecatcher(tag, eyeCatcher)) {
        throw new J9MemTagCheckError(tag, "Wrong eyecatcher. Expected 0x" + Long.toHexString(eyeCatcher) + " but was " + UDATA.cast(tag).getHexValue());
    }
    slots = U32Pointer.cast(tag);
    /*
		 * Could be unrolled into chained xors with a J9VM_ENV_DATA64
		 * conditional on the extra 2 U_32s
		 */
    for (int i = 0; i < (J9MemTag.SIZEOF / U32.SIZEOF); i++) {
        sum ^= slots.at(i).longValue();
    }
    if (J9BuildFlags.env_data64) {
        U32 a = new U32(UDATA.cast(tag).rightShift(32));
        U32 b = new U32(UDATA.cast(tag).bitAnd(U32.MAX));
        sum ^= a.longValue() ^ b.longValue();
    } else {
        sum ^= tag.longValue();
    }
    if (sum != 0) {
        throw new J9MemTagCheckError(tag, "J9MemTag sumcheck failed: " + sum);
    }
}

Example 4 with J9MemTagCheckError

use of com.ibm.j9ddr.vm29.pointer.helper.J9MemTagHelper.J9MemTagCheckError in project openj9 by eclipse.

the class J9MemTagCommands method corruptData.

/**
 * CorruptData handler used with J9MemTagIterator
 */
public void corruptData(String message, CorruptDataException e, boolean fatal) {
    if (e instanceof J9MemTagCheckError) {
        J9MemTagCheckError casted = (J9MemTagCheckError) e;
        out.println("J9MemTag check failed at " + Long.toHexString(casted.getAddress()) + ": " + message + " :" + e.getMessage());
    } else {
        e.printStackTrace(out);
    }
}